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IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING Preventing Oxygen Inhibition during Polymerizations. As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicals themselves. Free IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING Preventing Oxygen Inhibition during Polymerizations. As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicals themselves. Free IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: BIREFRINGENCE IN POLYCARBONATE Birefringence in Polycarbonate. Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-optic law, etc. The articles are very well written and I would recommend them to anyone working with glassy polymers, PC or otherwise. The first article (you probably should readthem
IT'S THE RHEO THING: PEANUT BUTTER RHEOLOGY Peanut Butter Rheology. Soft Matter, has short report (3 pages) about the rheology of peanut butter, but from a rather odd perspective, that of a metallurgist . We all know that peanut butter has a yield point, a point (defined by either a stress or a strain) that the material needs to be deformed beyond in order for itto flow.
IT'S THE RHEO THING: A CHEMICAL MYSTERY My wife and I were able to use our chemical knowledge this past week to solve a perplexing problem. I'll post first what we observed and then let you try and figure it out. IT'S THE RHEO THING: ALLOPHANATES Allophanates. The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches - "allophanate". Pronounced as "al-LOFF-a-nate", theterm
IT'S THE RHEO THING: GLUING A PLANE TOGETHER Gluing a Plane Together. It is not widely known by the general public that aircraft wings are usually glued on to the plane, not rivoted, bolted, or using some other mechanical fasteners. Which means that a thin layer of polymeric material is what is holding the plane up in the sky. It's not the wing or the engine or the Bernoulli principle [1 IT'S THE RHEO THING: ISOLATING THIXOTROPY FROM SHEAR THINNING Isolating Thixotropy from Shear Thinning. With non-Newtonian fluids, the viscosity is no longer constant. Depending on the flow conditions (and the material of course), the viscosity will decrease as the shear rate increases (shear thinning) or it will increase (shear thickening). In some cases as well, there is a time dependency - the IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: PLASTIC DEBRIS IN THE GREAT LAKES Being located pretty close to North America's Continental Pole of Inaccessibility , I can sleep well at night knowing that my trash is not ending up in the oceans, adding to any of the various "Garbage Patches" that are constantly in the news. (Besides, most of the trash here in town is incinerated and used to generate electricity.) Getting to the ocean is a major trip and not something IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: BIREFRINGENCE IN POLYCARBONATE Birefringence in Polycarbonate. Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-optic law, etc. The articles are very well written and I would recommend them to anyone working with glassy polymers, PC or otherwise. The first article (you probably should readthem
IT'S THE RHEO THING: A CHEMICAL MYSTERY My wife and I were able to use our chemical knowledge this past week to solve a perplexing problem. I'll post first what we observed and then let you try and figure it out. IT'S THE RHEO THING: PEANUT BUTTER RHEOLOGY Peanut Butter Rheology. Soft Matter, has short report (3 pages) about the rheology of peanut butter, but from a rather odd perspective, that of a metallurgist . We all know that peanut butter has a yield point, a point (defined by either a stress or a strain) that the material needs to be deformed beyond in order for itto flow.
IT'S THE RHEO THING: ALLOPHANATES Allophanates. The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches - "allophanate". Pronounced as "al-LOFF-a-nate", theterm
IT'S THE RHEO THING: GLUING A PLANE TOGETHER Gluing a Plane Together. It is not widely known by the general public that aircraft wings are usually glued on to the plane, not rivoted, bolted, or using some other mechanical fasteners. Which means that a thin layer of polymeric material is what is holding the plane up in the sky. It's not the wing or the engine or the Bernoulli principle [1 IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: ISOLATING THIXOTROPY FROM SHEAR THINNING Isolating Thixotropy from Shear Thinning. With non-Newtonian fluids, the viscosity is no longer constant. Depending on the flow conditions (and the material of course), the viscosity will decrease as the shear rate increases (shear thinning) or it will increase (shear thickening). In some cases as well, there is a time dependency - the IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: PLASTIC DEBRIS IN THE GREAT LAKES Being located pretty close to North America's Continental Pole of Inaccessibility , I can sleep well at night knowing that my trash is not ending up in the oceans, adding to any of the various "Garbage Patches" that are constantly in the news. (Besides, most of the trash here in town is incinerated and used to generate electricity.) Getting to the ocean is a major trip and not something IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: BIREFRINGENCE IN POLYCARBONATE Birefringence in Polycarbonate. Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-optic law, etc. The articles are very well written and I would recommend them to anyone working with glassy polymers, PC or otherwise. The first article (you probably should readthem
IT'S THE RHEO THING: A CHEMICAL MYSTERY My wife and I were able to use our chemical knowledge this past week to solve a perplexing problem. I'll post first what we observed and then let you try and figure it out. IT'S THE RHEO THING: PEANUT BUTTER RHEOLOGY Peanut Butter Rheology. Soft Matter, has short report (3 pages) about the rheology of peanut butter, but from a rather odd perspective, that of a metallurgist . We all know that peanut butter has a yield point, a point (defined by either a stress or a strain) that the material needs to be deformed beyond in order for itto flow.
IT'S THE RHEO THING: ALLOPHANATES Allophanates. The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches - "allophanate". Pronounced as "al-LOFF-a-nate", theterm
IT'S THE RHEO THING: GLUING A PLANE TOGETHER Gluing a Plane Together. It is not widely known by the general public that aircraft wings are usually glued on to the plane, not rivoted, bolted, or using some other mechanical fasteners. Which means that a thin layer of polymeric material is what is holding the plane up in the sky. It's not the wing or the engine or the Bernoulli principle [1 IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: ISOLATING THIXOTROPY FROM SHEAR THINNING Isolating Thixotropy from Shear Thinning. With non-Newtonian fluids, the viscosity is no longer constant. Depending on the flow conditions (and the material of course), the viscosity will decrease as the shear rate increases (shear thinning) or it will increase (shear thickening). In some cases as well, there is a time dependency - the IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: PLASTIC DEBRIS IN THE GREAT LAKES Being located pretty close to North America's Continental Pole of Inaccessibility , I can sleep well at night knowing that my trash is not ending up in the oceans, adding to any of the various "Garbage Patches" that are constantly in the news. (Besides, most of the trash here in town is incinerated and used to generate electricity.) Getting to the ocean is a major trip and not something IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY At low strains, the storage modulus, G', stays constant, but at higher strains, G' begins to drop. (Need a primer on G'? You can get it right here.)The flat section is the linear deformation region and is very important to many rheological measurements. IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL This page provides only a brief overview of the theory behind rheological characterization through dynamic mechanical analysis (DMA). To do this subject properly, you would need to write a whole book and that has in fact been done by multiple individuals, such as texts written by J.D. Ferry, Viscoelastic Properties of Polymers or the one by J. Dealy and K. Wissbrun, Melt Rheology and its Role IT'S THE RHEO THING: THE COX-MERZ RULE RULES I've always viewed the Cox-Merz Rule as my savior, despite it being difficult to roll off the lips smoothly. A workhorse test in rheology is dynamic mechanical analysis in which an oscillitory stress/strains is applied to the sample. IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT While industrial accidents with phosgene have been relatively rare, they do occur. Some recent examples are a leak that led to the death of a DuPont worker last year in West Virginia, and leaks in Thailand and China that in both cases also had a death, along with hundreds of injuries. BPA never did this to anyone. But not content to continue living with these problems, that creative bunch of IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE For reasons I've never understood, the most common search term that consistently, year-in, year-out brings people to this blog is "Cox-Merz rule" or some variation thereof. IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET Anonymous said "You can simulate real world conditions all you want, but nothing beats using the real world conditions." This is a really well-written sentence that underlines so much of what goes wrong with experimental research and drawing conclusions from data that is not reflective of conditions in reality. IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicalsthemselves.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND It is becoming common knowledge that ketchup is "thixotropic". More and more people are beginning to talk about it, which means that this is a good time to put the idea to the test. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON It's a simple enough question raised by a new research article (European Polymer Journal ($)): "What is the glass transition temperature of PTFE"?, but like so many measurements of PTFE, the answer always starts with "it's complicated". IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum.But now there's a
IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGY At low strains, the storage modulus, G', stays constant, but at higher strains, G' begins to drop. (Need a primer on G'? You can get it right here.)The flat section is the linear deformation region and is very important to many rheological measurements. IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL This page provides only a brief overview of the theory behind rheological characterization through dynamic mechanical analysis (DMA). To do this subject properly, you would need to write a whole book and that has in fact been done by multiple individuals, such as texts written by J.D. Ferry, Viscoelastic Properties of Polymers or the one by J. Dealy and K. Wissbrun, Melt Rheology and its Role IT'S THE RHEO THING: THE COX-MERZ RULE RULES I've always viewed the Cox-Merz Rule as my savior, despite it being difficult to roll off the lips smoothly. A workhorse test in rheology is dynamic mechanical analysis in which an oscillitory stress/strains is applied to the sample. IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT While industrial accidents with phosgene have been relatively rare, they do occur. Some recent examples are a leak that led to the death of a DuPont worker last year in West Virginia, and leaks in Thailand and China that in both cases also had a death, along with hundreds of injuries. BPA never did this to anyone. But not content to continue living with these problems, that creative bunch of IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE For reasons I've never understood, the most common search term that consistently, year-in, year-out brings people to this blog is "Cox-Merz rule" or some variation thereof. IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET Anonymous said "You can simulate real world conditions all you want, but nothing beats using the real world conditions." This is a really well-written sentence that underlines so much of what goes wrong with experimental research and drawing conclusions from data that is not reflective of conditions in reality. IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicalsthemselves.
IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND It is becoming common knowledge that ketchup is "thixotropic". More and more people are beginning to talk about it, which means that this is a good time to put the idea to the test. IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON It's a simple enough question raised by a new research article (European Polymer Journal ($)): "What is the glass transition temperature of PTFE"?, but like so many measurements of PTFE, the answer always starts with "it's complicated". IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum.But now there's a
IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL This page provides only a brief overview of the theory behind rheological characterization through dynamic mechanical analysis (DMA). To do this subject properly, you would need to write a whole book and that has in fact been done by multiple individuals, such as texts written by J.D. Ferry, Viscoelastic Properties of Polymers or the one by J. Dealy and K. Wissbrun, Melt Rheology and its Role IT'S THE RHEO THING: THE BIG 6 PLASTICS Compared to the chemical industry, the polymer industrial is pretty undiversified. Just 6 polymers, high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) dominatethe industry.
IT'S THE RHEO THING: ALLOPHANATES The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches- "allophanate".
IT'S THE RHEO THING: A CHEMICAL MYSTERY My wife and I were able to use our chemical knowledge this past week to solve a perplexing problem. I'll post first what we observed and then let you try and figure it out. IT'S THE RHEO THING: DROP-IN PLASTICS? A blog about all aspects of polymers - chemistry, physics, rheologyand business
IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum.But now there's a
IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS A blog about all aspects of polymers - chemistry, physics, rheologyand business
IT'S THE RHEO THING: GLUING A PLANE TOGETHER It is not widely known by the general public that aircraft wings are usually glued on to the plane, not rivoted, bolted, or using some other mechanical fasteners. IT'S THE RHEO THING: BIREFRINGENCE IN POLYCARBONATE Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-opticlaw, etc.
IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER BPA is not a plasticizer. Plain and simple. BPA (bisphenol A) is not a plasticizer. BPA is not an plastic additive. Plain and simple. BPA is not a plastic additive. IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGYDIFFERENCE BETWEEN LINEAR AND NONLINEAREXAMPLES OF LINEAR AND NONLINEARWHAT IS LINEAR AND NONLINEARFUNCTION LINEAR OR NONLINEARLINEAR AND NONLINEAR MODELWHAT IS A LINEAR AND NONLINEAR EQUATION The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING Preventing Oxygen Inhibition during Polymerizations. As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicals themselves. Free IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: ALLOPHANATES Allophanates. The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches - "allophanate". Pronounced as "al-LOFF-a-nate", theterm
IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: LINEAR AND NON-LINEAR RHEOLOGYDIFFERENCE BETWEEN LINEAR AND NONLINEAREXAMPLES OF LINEAR AND NONLINEARWHAT IS LINEAR AND NONLINEARFUNCTION LINEAR OR NONLINEARLINEAR AND NONLINEAR MODELWHAT IS A LINEAR AND NONLINEAR EQUATION The plot above was made using the strain sweep program which starts at the lowest strain measurements and increases the strain over time automatically. A sweep like this is done in about 2 minutes depending on how much the strain is increased between measurements. The problem with the output above is that it is wrong. IT'S THE RHEO THING: IS KETCHUP REALLY THIXOTROPIC? AND Over time, the viscosity drops, so yes, ketchup is thixotropic. I would have loved to have taken the data for this last plot, but I have the wrong type of rheometer for it , so I am borrowing a plot from TA Instruments. This plot shows that ketchup also has a yield stress. A certain amount of force is needed to get it moving in the firstplace.
IT'S THE RHEO THING: THE COX-MERZ RULE RULES I get asked about the difference quite a bit and thankfully there is the Cox-Merz rule. Simply put, the steady state shear viscosity at a given shear rate is equal to the dynamic viscosity at the same frequency: h () = h * (w) when = w. The rule is more-or-less empirical - it works for many common polymers but there is no (strong)theoretical
IT'S THE RHEO THING: THE REAL DANGER IN POLYCARBONATE (IT Polycarbonate (PC) is taking a lot of heat in the popular press these days because of the BPA (bisphenol A) that remains in it as a residual monomer. BPA is an estrogen mimic, but isn't really a concern at the levels found in polycarbonate. Even if all the hysteria about BPA leaching out of PC is true, nobody is suggesting that BPA will killyou.
IT'S THE RHEO THING: REAL WORLD UV DEGRADATION OF PET The blue diamond is the yellowness for the samples exposed to a fluorescent lamp for 2 continuous months. That point is well off the curve, and shows that sunlight is more more aggressive about degrading PET. This also re-emphasizes my point to ALWAYS run real world exposure controls. Accelerated aging is not just a matter of countingphotons
IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: PREVENTING OXYGEN INHIBITION DURING Preventing Oxygen Inhibition during Polymerizations. As chemists, we often work with oxygen sensitive materials and there are a variety of techniques for handling such materials. Today's post however, is about a slight variation of oxygen sensitivity - one where the reaction itself is oxygen sensitive, rather than the chemicals themselves. Free IT'S THE RHEO THING: A SUBSTITUTE FOR AQUA REGIA A Substitute for Aqua Regia. While not of any immediate use to us polymer people, I have some colleagues that use immense quantities of aqua regia and they found this interesting. Aqua regia as you may recall is a 1:3 mix of nitric acid and hydrochloric acid able to dissolve both gold and platinum. But now there's a (semi-) organicoption:
IT'S THE RHEO THING: ALLOPHANATES Allophanates. The most bizarre term in all of polymer chemistry, and probably organic chemistry as well is that awful word from polyurethane chemistry that sticks to your tongue and leaves your mouth with all the ungainliness of a 3-legged horse wearing a cast and using crutches - "allophanate". Pronounced as "al-LOFF-a-nate", theterm
IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: FUNDAMENTALS OF DYNAMIC MECHANICAL A common output of DMA rheology is tan (δ) = G"/G', called the loss tangent. So far we have worked with 7 variables: G', G", G*, η*, ω, δ and t, but that is only the beginning. The inverse of G* is the complex compliance, J* = 1/G*, and just like with the complex modulus, the complex compliance can be broken into a storage compliance J' and IT'S THE RHEO THING: THE GLASS TRANSITION OF TEFLON As a result, there is a significant amount of amorphous material trapped in the sample and this material is what exhibits the glass transition. Using dynamic mechanical analysis, the authors found three transitions which they labeled, α, β and γ. The β-transition they quickly identified as a crystalline rearrangement based on existingresearch.
IT'S THE RHEO THING: A DERIVATION OF THE COX-MERZ RULE The Cox-Merz rule is a empirical observation that h () = h * (w) when = w. The importance of this is that it allows a tremendous amount of lab work to have significance in non-lab (production) settings. In the lab, viscosity is normally measured by imposing sinusoidal stresses or strains on a sample and observing the mechanical response. IT'S THE RHEO THING: THE DEBORAH AND WEISSENBERG NUMBERS The Deborah and Weissenberg Numbers. Engineers have always loved dimensionless numbers , groups of variables where the units cancel leaving them free from the chosen system of measurement. (i.e., the Reynold number for a system has the same value when measured in SI or English units.) Rheology is generally lacking in dimensionless numbers IT'S THE RHEO THING: A CHEMICAL MYSTERY My wife and I were able to use our chemical knowledge this past week to solve a perplexing problem. I'll post first what we observed and then let you try and figure it out. IT'S THE RHEO THING: BIREFRINGENCE IN POLYCARBONATE Birefringence in Polycarbonate. Highline Polycarbonate has the second of series about the internal optical properties of polycarbonate - birefringence, the stress-optic law, etc. The articles are very well written and I would recommend them to anyone working with glassy polymers, PC or otherwise. The first article (you probably should readthem
IT'S THE RHEO THING: GLUING A PLANE TOGETHER Gluing a Plane Together. It is not widely known by the general public that aircraft wings are usually glued on to the plane, not rivoted, bolted, or using some other mechanical fasteners. Which means that a thin layer of polymeric material is what is holding the plane up in the sky. It's not the wing or the engine or the Bernoulli principle [1 IT'S THE RHEO THING: BPA IS NOT A PLASTICIZER Plasticizers are compounds that are added to an existing plastic to make it more plastic-y (meaning able to undergo irreversible deformation). They are commonly phthalates, but they can be other compounds as well. BPA on the other, is a monomer, which when reacted with other monomers produces a plastic. It does not change theproperties of an
IT'S THE RHEO THING: FAIRLIFE FOLLOWUP Last week I wrote the bottle that contains Fairlife chocolate milk and in particular about how confusing the recycling code at the bottom is. It's the number 7, but instead of saying "other" as it should, it says "PETE" (which corresponds to the number 1 code). I IT'S THE RHEO THING: "PLASTIC DEBRIS IN THE OPEN OCEAN" The Proceedings of the National Academy of Sciences has an early online report regarding ocean plastic and the results are not exactly supportive of what is commonly accepted. In particular, the research found a profound absence of very small plastic pieces and thereby a corresponding lack of total plastic in the open ocean. Everything flows, but only the macromolecules are worth the time. FRIDAY, JUNE 23, 2017 A HOUSE BUILT FROM PLASTIC BOTTLES Plastic beverage bottles are considered by many to be a bane of modern society, but their durability and strength has an appeal that some people are able to take advantage of. In Argentina, there is AHOUSE
constructed from these bottles. Not just the exterior wallsbut
also the bed
While this may seem like a novel idea, a little digging shows that it is not. Such houses EXIST AROUND THE WORLD. Just
don't expect to see one in my yard soon however. I suspect that my wife, the neighbors and the City of Woodbury would disapprove. All of this demonstrates many of the strengths (literally) of water bottles. While most people focus exclusively on what only during its brief life in the hands of the consumer, I'VE MENTIONED BEFORE just some of the many requirements that a water bottle needs to meet, many of which the consumer is not directly aware of. Having a long life before it degrades can be good or bad, all depending on theapplication.
These houses are new to me, although the use of plastic water bottles in construction isn't. I WROTE in the past about the use of water bottles in roofs, either as a light source or as a thatching material, all of which shows further the limitless of human creativity. I doubt that this is the last new use we will see here for such bottles. 322 0 0 0 0Google 5Reddit 0StumbleUpon 0Digg 0Evernote 1 Posted by John at 8:53 AM105 comments
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Labels: construction, packaging
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MONDAY, JUNE 19, 2017 PLASTIC RICE AND OTHER FAKE FOODS One story that seems to never die on the internet are claims of"plastic rice" (1
,
2
and 3
.)
I find the endless claims very strange, not only because of their endlessness, but also because the whole idea of making rice from plastic in the first place is pretty idiotic for more than one reason. As was noted in the Bangalore Mirror article, > _'Rice is being sold at Rs 40-Rs 50 per kg while if at all one has > to make plastic rice __, the cost would be somewhere around Rs > 200 per kg. So, I don't think there is any logic in this.'_ Further, plastic rice would be immediately obvious to the consumer with the texture being extremely different from real rice, (assuming the rice was cooked even close to properly). What really hits me as funny is all the "testing" that the articles do to ascertain if rice is plastic or not. Burn some with a match and you can easily tell the difference. I'm old school enough to remember kits available for purchase that relied on this technique for quick-and-easy plastic identification. While the kits no longer seem available, THE INFORMATION STILL IS . And anyone who has spent much time in a plastic processing plant will rapidly be able to tell what resin is being run just from the aroma in the air. But getting back to the costing of creating fake food, rice (and eggs) and other low cost food items are worth the bother. If your are going to create fake food, go for something expensive. Fake caviar would be a good starting point. Hydrogels are readily available. and already used in bubble tea. Add a little bit of fish flavor, salt and color - voila! cheap caviar, and most people wouldn't even know the difference - PLUS, there would be much bigger profit margins available. But alas, IT'S ALREADY BEEN DONE.
Ok, so that idea didn't work out. How about something else, like FAKECHEESE ...
455 2 0 0 0Google 5Reddit 0StumbleUpon 0Digg 0Evernote 0 Posted by John at 7:47 AM69 comments
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FRIDAY, JUNE 16, 2017 FROM MAGMA TO WILDEBEESTS TO SMARTPHONE Today's post is going to cover a wide range of topics, starting with magma rheology, and connecting to that wildebeests and smartphones. It might be too much for a Friday, so if you hold off reading this until Monday, that's just fine. This rambling journey all started a post from ATLAS OBSCURA (a really great site for wasting huge amounts of time on fascinating, relatively unknown items from around the world). It mentions a unique volcano in northern Tanzania, Ol Doinyo Lengai, which spews carbonatite lava instead of the usual silicate magma. Magma is still magma - hot, molten rocks, but the lack of silica in the magma is very unusual. This is the only active volcano in the world that has carbonatite magma (more on the inactive volcanoes in a minute). Silica, as you may know, is capable of forming long chains thereby increasing the viscosity of normal magma. It also increases the temperature at which the magma needs to be heated in order to flow. Carbonatite magmas cannot form such long chains, so their magmas can be of lower temperature (500 oC vs. 1100 oC) and viscosity. (At 500 oC, the stuff isn't even glowing red!) And it appears to freeze pretty quickly, leading to some exotic formations: The Atlas Obscura article is pretty short, but some more digging turned up some further fascinating connections. The WIKIPEDIA PAGEfor the volcano
states that
> _"The carbonatite ash spread over the surrounding grasslands leads > to a uniquely succulent, enriched pasture. This makes the area a > vital stage on the annual wildebeest beast migration, where it > becomes the nursery for the birth of several thousand calves."_ And further digging led me to THIS ARTICLE by a Dennsion University Professor. The whole basis for some volcanoes being silicic and others being carbonic is still unresolved. Weirder yet is that Ol Doinyo Lengai used to be silicic and only recently has become carbonic. And still weirder yet is that carbonic magmas are associated with deposits of rare earths elements. The largest rare earth mine in China as well as the rare earth mine in the US are both located in carbonic deposits, and rare earths are crucial components for smartphones, supermagnets and other items of modern technology. Prior to this, I never new that there were such variations in magma, let alone that they would have such profound impacts for those of us living on the surface of the planet. 224 1 0 0 0Google 4Reddit 0StumbleUpon 0Digg 0Evernote 0 Posted by John at 8:29 AM61 comments
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THURSDAY, JUNE 15, 2017 TWO WORLDS COLLIDE IN 1 PHOTO This is one strange photo:So
many questions. So many. Staged photos (and yes, this obviously is one) will often do that, but this one seems to have gone off in athird dimension.
This was on the walls last month for a 50th class reunion so the age of image, the clothing and other fashion items are not what's strange. Nor is the lack of PPE, giving the time the original photo was taken. The biggest question to me is why is the instructor holding a condenser(?) with the tip just few inches away from the throat of the student? It's looks like the poor lad is being force to read a signed confession or otherwise threatened. The round-bottom flask in apparent isolation is also odd. The writing on the chalkboard is equally strange. Not the the left side, where you have the conversion between Fahrenheit and Celsius - that's fine. Rather it's the (repeated) equation in the middle that is the head scratcher. _It's a formula for cutting speed and it's used with machining equipment._ Two worlds colliding - machinists and chemists. I strongly suspect that at the very least, the instructor had no chemistry experience. The same would be true of the photographer. And certainly no one thought that the photo would be preserved for 50 years. I haven't been able to find any further details; it's just an old photo kicking around that was made into a poster. Keep that in mind next time you take a photo. It may end up being a poster somewhere where you least expect it and no backstory to explain it. Rather frightening, huh? 264 0 0 0 0Google 5Reddit 0StumbleUpon 0Digg 0Evernote 0 Posted by John at 9:08 AM54 comments
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TUESDAY, JUNE 13, 2017 CATCHING UP WITH THE ACTIVIST INVESTORS AT DOW AND DUPONT It's been quite a while since I wrote about the activist investors at Dow and Dupont, Daniel Loeb and Nelson Peltz, respectively. I figured the merger of the two companies would be the end of it, particularly since the merger would be immediately followed by splitting the company into three parts in order to satisfy regulatory bodies. And that splitting was what both activists desired when they initially took up their positions (that plus a seat on the company's respective boards). But as the merger has dragged on (it was first proposed in December of 2015(!) and still isn't done), it's time to update what Loeb and Peltz are up to. Peltz first. His position is easy to describe. HE'S SOLD OFF MOST OFIT
so that he can be now bug Proctor & Gamble, GE, Sysco and Mondelez. That's truly shocking. As one writer STATED,
> _"orporate executives might want to think twice before relying on > hedge fund matchmakers. It appears they are not even patient enough > to stick around for the wedding."_ Loeb on the other hand, seems to be getting rather impatient and the longer he waits, the bigger of a slice of wedding cake he expects. He is asking why cut the cake into 3 slices when you can CUT IT INTO 6SLICES
,
and we all know 6 is bigger than 3, right? (Just like AN AMP THAT GOES TO 11 is better than one that goes to just 10.) And in making the additional slices, everyone gets an extra $20billion dollars.
If that math doesn't make sense to you, well, I've noted in the past that Loeb has the math skills of a high school student (1and 2
),
and a lousy student at that. Having lots of money and wealthy friends doesn't make you intelligent, but it will get you access to a microphone, strangely. If Loeb really believes that the combined value of the new company cut 3 ways is worth an extra $20 billion, then the market will quickly realize its mistake and value the companies appropriately with a larger stock price. And if that still isn't fast enough, then I suggest that Loeb get some of his rich friends together to buy the undervalued companies and split them yourselves. It's an old idea, but I believe it's called "putting your money where yourmouth is".
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Dow , DuPont
MONDAY, JUNE 12, 2017 PLASTIC BOTTLES AND TERROR ATTACKS The Metropolitan Police RELEASED PHOTOS YESTERDAY of some of additional "tools" used in the recent terror attacks on London Bridge. Surprisingly, they included plastic water bottles.The
bottles had been covered with duct tape to create an element of mystery or the unknown and were attached to a belt worn by the attackers. They weren't filled with anything, but I have to admit if I saw a group of knife-yielding attackers wearing such equipment (assuming I could completely overlook the knives), they would lookreal enough for me.
I'm assuming the bottles looked in better shape prior to the attack, and upon closer examination in an environment in which no one's safety is a concern, the lack of visible wires makes the devices look suspiciously fake. Even after the attackers were "neutralized", the bottles would still need to be considered a serious bomb threat until decided otherwise which leads to more concerns for authorities even after an event looks to be over. I don't know if this is the first time "duct-taped-water-bottles-as-real-looking explosive devices has been used, but I would expect to see more of them in future attacks around the world (a statement that saddens me to write). All of this really emphasizes that "the belts made the bravery of those who took on the attackers even more remarkable". 427 24 9 0 0Google 14Reddit 0StumbleUpon 0Digg 0Evernote 2 Posted by John at 11:57 AM5 comments
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