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Questions tagged [polymers]

For questions about synthetic or natural polymers, their chemical or physical properties, and their synthesis, etc.

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Why does the degree of polymerisation remain the same throughout chain-growth polymerisation?

It is known that the degree of polymerisation, which is the average number of monomer units in each polymer chain formed, increases as the reaction proceeds for step-growth polymerisation as longer ...
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Polymer that has aldehyde and carboxylic acid functional group

I'm currently identifying an unknown polymer sample and I found out from raman spectroscopy that it may contain aldehyde and carboxylic acid functional groups (and possibly ketone too). I was looking ...
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Do all polymers contain either carbon or silicon?

Is either carbon or silicon present in every known polymer? If not, is there a small group of elements that, between them, are present in every known polymer, or can polymers be based on a lot of ...
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Polyethylene terephtalate Biodegradability [on hold]

I'm looking into plastics and how they break down. I have learned 3 ways oxo-biodegradation, photodegradation and thermaldegradation. Does anyone know how PET (polyethylene terephtalate) degrades?
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on Water based polyurethane floor: do I need to neutralize after mopping with pH 9 mopping solution [on hold]

on Water based polyurethane floor: do I need to neutralize after mopping with pH 9 mopping solution? We need the cleaning power of that slightly alkaline solution but some people tell me the ...
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Can any body Suggest me a set up that I can build it up to study the surface roughness of transparent polymeric fibres?

I need to study the surface of nylon-6 blank fibres with a thickness of nearly 40 micrometre, I work in optics lab with many optical components such as beam splitters, lenses, mirrors ... etc, can I ...
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Where can I look for a short chain photopolymer?

I am by no means an expert in this field, so please be patient with my explanation. I am looking for a photopolymer with very specific properties. I am not sure how realistic it is to find such a ...
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Spraying aluminium hydroxide nanoparticles onto PLA as fire retardant?

Several scientific papers study FR-PLA (fire resistant PLA) in which Aluminium Hydroxide nanoparticles are melt blended into the PLA (example source: Advances in Flame Retardant Poly(Lactic Acid). ...
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diamine synthesis

I want to synthesize a new polyimide based on new diamine. In the first step of the synthesis of this diamine, my monomer was added to mixture of 1-chloro-4-nitrobenzene and potassium carbonate in ...
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Hardened polyurethane remover

I've looked at the MSDS of a couple of products for removing hardened polyurethane (PU) foam. Both contained only ethanolamine as a dangerous substance, but only between 1-5%. So I'm guessing this ...
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Mixing of molecular orbitals in polyatomic molecules

I am trying to solve the following Hamiltonian,$$H=-\frac{1}{2}\nabla^{2}-\sum_{i=1}^{10}\frac{1}{|\vec{r}-\vec{R_{i}}|}$$ Here $Z=1$ . To get all ther molecular orbitals of this system. I took the ...
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Some information about DOWXV503 [closed]

I want to know about the attractor DOWXV503. Is there any scientific book or article about this material? Any information is useful and it will be appreciated.
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702 views

Can a long polymer chain interact with itself via van der Waals forces?

It is known that van der Waals interaction is an intermolecular forces. So is it possible that a long polymer chain interacting with itself via non-bonded interactions (such as van der Waals forces / ...
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How can I prevent my spin-coated silica thin film from cracking when I heat it up?

I am spin-coating a porous silica solution on a glass microscope coverslip, and then heating the resulting thin film to $\pu{350 °C}$, in an attempt to create a thin film of porous silica sol gel. I ...
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Molecular Orbital Mixing to get the Molecular Orbitals of a large molecule

I am trying to get the molecular orbital for arbitrarily placed nuclear centres (identical). In other words , I am trying to solve the following one electron hamiltonian. $$h=-\dfrac{1}{2}\nabla^{2}-\...
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1answer
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In search of a safe and inexpensive solvent that can dissolve depolymerized polypropylene waste plastic

I work at a place where we depolymerize post consumer waste polypropylene waste plastic through a thermal catalytic conversion process. During process shutdown we have to clear up the vessels which ...
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Are linear alkanes polymers? [duplicate]

Let me ask a basic question. Wikipedia defines a polymer as A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Now, can we think of a large linear alkane as a ...
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Is it possible to make polyethylene in a high school laboratory?

We learned how to make small amounts of ethene from ethanol using sulfuric acid. Is there a way to make a visible amount of polyethylene from that using materials I could get for a school lab? We can'...
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Do self-growing hydrogels grow and strengthen infinitely?

Recently, there was a publication [1] (/., YouTube) on self-growing materials using mechanoradically-generated double-network (DN) hydrogels, closely resembling self-strengthening of muscles. We ...
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1answer
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Adhesion of polymerized fats to cast iron

I'm trying to make an informed decision as to which oil is best to use for cast iron seasoning. I've read all kinds of conflicting information online and the only consistency seems to be that ...
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1answer
132 views

Polymer Chemistry NMR question [closed]

I am extremely new to both polymer chemistry and NMR. I am struggling with the following question: A proton NMR is used to attempt to quantify the molecular weight of a poly(ethylene oxide) molecule ...
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1answer
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Dissociation behaviour of polyelectrolytes

Assuming a solution of 100 polycationic molecules, each of them carrying 100 amino groups and an apparent pKa of 6.5. Would it mean that, at a pH of 6.5, 50 molecules will be fully protonated 50 ...
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What is ultimate decomposion product of Teflon (PTFE) in environment

There is a lot information available regarding thermal decomposition e.g. burning, but what happens to PTFE in ordinary environmental circumstances? Or if time for degradation is short enough, what ...
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How to write correct NMR integrals in a formula?

for my masterthesis I want to include the Equation how I calculate my conversion in a polymer reaction. It is pretty easy, but I still want to write it down. Basicly the equation is: (Integral A ...
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1answer
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What is the refractive index of poly(methacrylamide)?

I've been looking for the index of refraction for poly(methacrylamide). I searched several vendors and in https://polymerdatabase.com/ with no success. Is there any database where I can find this ...
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Question during radius of gyration calculation from XYZ trajectoris of atoms

I have molecular dynamic simulation result of 100 polymer molecules (liquid), and I'm trying to calculate the radius of gyration using atomistic mass, molecular mass, and xyz coordinate of atoms. I'm ...
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How long does a linear hydrocarbon chain have to be before we call it polyethylene?

Might be a really silly question here but here goes. Polyethylene is a polymer with a repeating unit of just 2 carbon atoms attacked to 2 hydrogens each which connect to other repeat units. This ...
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Why is Buna-S called so?

Styrene Butadiene synthetic rubber is also called Buna-S. It is the abbreviation of Butadiene (Bu) Sodium (Na) Styrene (S). Why is Sodium included?
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How to align povidone-iodine molecules in order to look for optical polarization?

In this answer I mention how early polarizing filters (e.g. sunglasses) were made by doping a polymer with iodine atoms and then stretching the film to orient the polymer molecules. Electrons donated ...
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Role of substituents in radical initialized polymerization

Here, the answer given is (iv), and I don't see the reason why methoxyethene is not forming an addition polymer with radical initiators. Clearly, the first option will form polystyrene and the second, ...
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How to remove MEHQ from Methacrylic acid monomer without reduced pressure distillation?

I am aware that the standard way to remove MEHQ from Methacrylic Acid is to perform reduced pressure distillation. The papers I see suggest using ~ 10 Torr pressure to perform distillation. Sandler's ...
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2answers
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Are the bonds in the monomers at the end of a polymer filled or unfilled?

In polymers the bonds between monomers are changed, usually from double to single1, to form a long-chain polymer with the now single bond joining another monomer. But in the monomers at the very ends ...
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What is a “tri-salt polymer” as described by this product that eliminates and prevents mold?

This answer mentions an anti-mold product called Concrobium Mold Control. The FAQ linked on their website says: Q: I see Sodium Carbonate listed on the label. Is Concrobium Mold Control just Sodium ...
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Can superglue (cyanoacrylite) be thinned with acetone and still harden?

I'm looking for something with an extremely low viscosity to use as a binder for cold casting iron oxide with very fine detail (it's to make a slotted winding core for an electric motor with $\pu{1mm}$...
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Why does lavender oil dissolve plastic?

A few weeks ago I decided to harvest the lavender in my garden and put it through a still to extract the essential oils. The still in question is essentially just an air cooled condenser. I collected ...
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How can the solid state structure of cyclopentadienyllithium be explained?

In the solid state, LiCp adopts a polymeric multidecker structure where Li atoms are sandwiched between two Cp rings (shown in this diagram from Organometallics 1997, 16 (17), 3855–3858): If we ...
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Are there chiral carbons in PVC polymers?

PVC polymers are formed from the monomer CH2=CHCl. Below picture is a section of PVC molecule. Is there any chiral carbon centre in this polymer molecule. If yes, then how? I have a source of CAIE ...
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Are polyhydroquinones considered to be polyphenols?

Looking at the Wikipedia article for polyphenol, I was struck by how the monomer units shown are all substituted meta or ortho for the hydroxyl groups. https://en.wikipedia.org/wiki/Polyphenol#...
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Why is FEP transparent and PTFE not?

fluorinated ethylene propylene (FEP) is close relative of poly(tetra-fluoroethylene) (PTFE), both only contain fluorine and carbon atoms,both have very similiar properties yet FEP is relatively ...
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What's the difference between FFKM and PTFE?

These two fluorocarbon polymers seem to me very similar, the only difference I see is that FFKM is elastomer while PTFE aka Teflon is more of hard type of plastic. Isn't FFKM just PTFE with lower ...
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Do conjugated polymers absorb very low energy photons?

I was reading that in conjugated compounds, the extent of conjugation decides what wavelength photon it can absorb. Longer the conjugation "chain", lesser the photon energy required. So, molecules ...
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Why are some chemicals packaged in incompatable containers?

I've noticed that some organic chemicals are sold in HDPE containers despite compatibility charts indicating that such containers are not appropriate acetone. For example, this acetone listing from ...
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Will PAEK polymers hydrolyze in concentrated sulfuric acid?

One of my duties at the company where I work is to perform intrinsic viscosity (IV) experiments on PAEK (poly(arly ether ketone)) polymers. These polymers don't dissolve well in most solvents, so the ...
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Polycarbonate resistance to acids

If polycarbonate plastic is a polar material with ester bond linkages which usually hydrolyze in acids, why is it resistant to both weak and strong acids (as polar substances)?
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Non-conventional polymers

IUPAC defines a monomer as, A molecule which can undergo polymerisation thereby contributing constitutional units to the essential structure of a macromolecule. Bearing this in mind, I thought ...
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What is the softening temperature of styrofoam?

Does anybody know the softening temperature of styrofoam (expanded polystyrene)? By styrofoam I mean the solid made of expanded polystyrene balls used in packaging.
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What's the monomer in a polycarbonate?

I know what the repeating unit is, but what's the monomer in a polycarbonate?
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Thermoplastic & Thermoset adhesives:

I have a question that is bothering me since few weeks. I'm not a chemist, nor I have any experience with polymers theory, but: Epoxy - is defined on Wikipedia as a thermoset polymer as a process of ...
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Oligomer Terminology

As we know, dimers, trimers etc. can be produced from a certain amount monomers. In the case of a dimer being produced, two monomers dimerise. Let's take an example of a dimer (glycine anhydride): ...
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Why is polyethylene not called polymethylene?

I understand that the monomer that polymerises to give polyethylene is an ethylene, but after polymerisation, the smallest repeating monomer in polyethylene seems to be a methyl and not an ethyl. So ...