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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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How does (E)CA glue ("super glue", "crazy glue", etc.) cure?

I use CA glue† very frequently in my shop, but I'm not entirely sure how it works. I've noticed three main modes of curing, I've emphasized the key observations: When dispensed, it will remain fluid ...
Jason C's user avatar
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7 votes
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97 views

Do "random" "2D" polymers constrained to a box actually form "space filling" curves?

Background: The self avoiding walk model is (allegedly) a reasonable model for polymers, at least with respect to certain "universal" (i.e. lattice independent) constants -- see section 1.1. in this ...
Elle Najt's user avatar
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6 votes
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Why is the rubber tip of my capacitive stylus no longer conductive?

In 2014, so eight years ago, I bought five styluses from China. Cheap stuff obviously. They worked fine while I used them, but soon after they were just left in a drawer. Last night I realized that ...
Mads Skjern's user avatar
6 votes
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610 views

Thermophysical properties of liquid Galden LS 230 between 25 °C and 230 °C

I'm looking for thermophysical properties of Galden LS 230, a liquid polymer (PFPE) produced by Solvay (https://www.solvay.com/en/markets-and-products/featured-products/Galden.html) at temperatures ...
Christoph's user avatar
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How to dissolve a strong resin in difficult situation?

The resin is made up from two components: Component A: silicic acid, sodium salt (less than 10% sodium silicate) Component B: Diphenylmethane-4,4'-Diisocyanate, isomers and homologs (MDI,Polymer-MDI)...
Stuck's user avatar
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5 votes
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63 views

Dependence of elasticity on temperature and degree of vulcanization of typical commercial rubber band

I am doing a school experiment that tries to find how the elasticity of rubber band depends on temperature. From all the research I have done, theory suggests stress to increase linearly with ...
Simon's user avatar
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77 views

Oxygen tolerant RAFT polymerization using AIBN?

I want to do some RAFT polymerizations but don't have a nitrogen line at the moment. It seems that people have recently implemented oxygen scavenging strategies to enable open-air RAFT polymerization. ...
toodles's user avatar
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What determines 3D printing material compatibility?

3D printing, specifically the type common for consumers FDM or FFF, involves laying down thin (typically 0.1 to 0.2mm) layers of molten plastic. Modern consumer printers can use various filaments: PLA,...
user2152081's user avatar
5 votes
0 answers
180 views

Why do aldehydes polymerize faster in the cold?

In amateur perfumery, raw chemicals are usually stored in sealed bottles in refrigerators/freezers to reduce decomposition rates. However, aldehydes are tricky to store for long periods of time ...
Peter Richter's user avatar
5 votes
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191 views

Side chain formation in polymerisation of ethylene

I am having difficulty understanding (or at least need confirmation of my understanding) of this diagram regarding the formation of sidechains of polyethylene. If someone could explain it, that would ...
Michael Mshtc's user avatar
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177 views

Regioselectivity in Ziegler–Natta polymerisation of α-olefins

Why does the Ziegler–Natta polymerization display the regioselectivity shown in the image? Internal nucleophiles (coordinated to the metal) should attack the alkene on the less substituted end, like ...
EJC's user avatar
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UV curable adhesive

I'm looking for a UV curable adhesive that can be removed without peeling or burning. Ideal removal would be some kind of solvent over a relatively short period of time. I also need it to have a ...
Felix Castor's user avatar
4 votes
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110 views

How to estimate the mobility constant and the surface energy parameter in the Cahn-Hilliard equation?

As a mathematician, I want to simulate phase separations with the Cahn-Hilliard equation $$ \frac{\partial c}{\partial t} = M \Delta \bigg(\frac{\partial \mu}{\partial c} - \kappa \Delta c \bigg), $$ ...
Henning's user avatar
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Rate of polymerization for copolymers with two monomers

I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r_\mathrm{p}$ is $$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
Nebula's user avatar
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What effect would decreasing melt viscosity by increasing melt temperature have on filler disaggregation in an extruder/compounder?

PLA has a melting point of around 150-160 degrees Celcius (the grade I am working with). I have microcellulosic fillers with aspect ratios that I am introducing to the polymer for compounding in a ...
Beenum's user avatar
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449 views

Does (BeCl2)n have 3-center-4-electron-bonding or not?

The title really explains what the issue is here. I would think that it has multicenter bonding akin to $\ce{(BeH2)_n}$ polymer, because they are pretty much iso-structural (although it shouldn't have ...
napstablook's user avatar
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Would the hydrogen-bonded polymer hexaamminecobalt(III) hexakis(trifluoromethyl)cobaltate(III) be soluble in water?

It is clear that both the hexaamminecobalt(III) ion and the hexakis(trifluoromethyl)cobaltate(III) ion are both low spin (the former is already low spin, and the trifluoromethyl ligand is clearly ...
Kanghun Kim's user avatar
4 votes
0 answers
168 views

Permeability of Nafion membrane

Nafion membrane is used as a proton exchange membrane (PEM) in fuel cells due to its selectively high permeability to hydronium ions $(\ce{H3O+})$ and water. A permeability study was done on small ...
C.X.F.'s user avatar
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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 ...
uhoh's user avatar
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Why does viscosity decrease when divalent cations are dissolved into aqueous solutions of sodium carboxymethylcellulose?

Sodium Carboxymethylcellulose (CMC/NaCMC/Aqualon) is a common product used in many instances for its unique properties, especially its ability to make solutions viscous. It is well known that the ...
Sam's user avatar
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0 answers
62 views

Is there a model for (quality of) two-component-polymerization (dependent on e.g. concentration)?

Sadly my chemistry background is only from high school (I'm a roboticist), but I try my best to explain the problem: Situation: Lets say I have two water based solutions/suspensions. One contains ...
Mofef's user avatar
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Gilman Reagent with vinyl chloride

What are the products formed when vinyl chloride reacts with dimethyl copper? I thought the product formed would be propene. But answer given is PolyVinylChloride. How does polymerization take place?
Aditya Dev's user avatar
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What are the dangers of melting HDPE and silicone? Is it even possible?

I've searched the internet and couldn't find a specific answer. There doesn't seem to be a single recycling company that takes empty silicone tubes (also know as mastic tubes) and recycles them. As a ...
Khalid's user avatar
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0 answers
378 views

Why the backbone of polylactic acid's repeating unit contains only one oxygen?

The monomer unit of polylactic acid is $\ce{CH_3-CH(OH)-CO_2H}$: So why the backbone of the repeating unit is $\ce{-C-C-O -}$: and not $\ce{-O-C-C-O -}$?
Sparkler's user avatar
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3 votes
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104 views

Chemical Mechanism Behind Water-Soluble Ink

I came across water-soluble ink pens designed for creating temporary fabric marks, particularly in cross-stitch stamping. These ink dissolve in water, transforming water into a colorful liquid, while ...
Fast Snail's user avatar
3 votes
0 answers
29 views

Can multispectral imaging be used for identification of materials, substituting for hyperspectral imaging?

Nowadays a lot of research and applications are using Hyperspectral Imaging for identification and segregation of plastics by material. But the cost of a HSI system is quite high. Could a ...
Aether's user avatar
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34 views

Is the "heat or UV" necessary for PVC10 + Cl => CPVC10 catalytic or endothermic and if endothermic how much energy?

Production of Chlorinated PolyVinyl Chloride (CPVC) from PVC and chlorine requires incorporating about one part chlorine in 10 PCV to achieve around 63% chlorine mass CPVC. This reaction is "...
James Bowery's user avatar
3 votes
0 answers
43 views

How do polyurethane varnishes cure after only the solvent evaporates

How do polyurethane varnishes cure after only the solvent evaporates? I believe that polyurethane varnishes have as components isocyanates & polyols that react to form the polyurethane portion of ...
Tempus Nomen's user avatar
3 votes
0 answers
38 views

Why are certain hot polycarbonate films stickier than others? Molecular weight? Hydrolysis?

In van der waals dry transfer, we pick up flakes of materials such as graphene using polymer films. The material is exfoliated onto an SiO2 covered wafer and picked off using the polymer film. It's ...
Evan's user avatar
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3 votes
0 answers
123 views

What is the number of Gaussian chains of network per unit volume of rubber?

In this chapter, page 70, I encountered the term `Gaussian chains of network'. In equation 3.34 (page 73) of this chapter, the phrase 'n is the number of moles of Gaussian chains' occurs in the ...
Riemann's user avatar
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3 votes
0 answers
65 views

1,1-Diphenylethylene subproduct/impurity

I'm working with 1,1-diphenylethylene and I've observed that, if left at room temperature in the air atmosphere, a white insoluble powder forms. I'm unable so dissolve this powder in every solvent ...
user avatar
3 votes
0 answers
47 views

How to adjust selectivity of gas-permeable PDMS membranes for environmental applications?

I have an idea about making an environmental sensor that uses a gas-permeable membrane (GMP) and how its probe could be submerged in a water source with an off the shelf gas sensor. So far, my ...
John P Santos's user avatar
3 votes
0 answers
49 views

Preferred radical attack on a polyester

My question concerns the relative stability of a radical next to an ester oxygen compared to a radical next to an ester carbonyl carbon. The stabilizing effect of the electron pairs of ether oxygen ...
Lothar Maier's user avatar
3 votes
0 answers
82 views

Safety concerns (Cyanide): Dicyandiamide + Polyamine condensation reaction

I am attempting to synthesize a poly-amine polymer by condensation between dicyandiamide (also known as cyanoguanidine and dicyandiamine) and diethyltriamine. The polymer is a kind of dye fixative ...
Juan Perez's user avatar
3 votes
0 answers
140 views

What is the structural formula of a monomer of hydroxypropyl methylcellulose?

I'm studying the properties of the polymer hydroxypropyl methylcellulose (HPMC) with the static scattering technique. I'm trying to interpret the molar mass obtained with a Zimm plot, that is $\pu{(3....
user avatar
3 votes
0 answers
80 views

Can a ferrite magnet be impregnated with polymer to reduce its fragility?

Ferrite magnet is a ceramic material and consists of agglomerated crystalline domains with spinel structure. Like other ceramic materials, ferrite magnets are brittle. For example, here is a photo of ...
andselisk's user avatar
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3 votes
0 answers
200 views

Remove sticky PDMS from glasses slides

I prepared some PDMS mixing a Sylgard 186 (elastomer) and a curing agent with 10:1 ratio. I sucked all the bubbles and I sandwiched the PDMS between two glass slides to get flat surfaces. Finally I ...
Mickey Martini's user avatar
3 votes
0 answers
294 views

How can I solubilize fragrance oil into polyvinyl acetate/clear glue?

I'm a high school student who makes slime for fun, using polyvinyl acetate (PVA) glue and borax as my main ingredients. Earlier, I had the idea of adding fragrance oils to clear glue. However, because ...
Marcus's user avatar
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3 votes
0 answers
83 views

Can PDMS silicone be produced with dichloromethane?

I was taking a simulated admission test for a Technology Institute (Brazilian ITA) and one of the questions asked for the production of PDMS silicone via these described steps: Reaction of $\ce{SiO2}$...
Leandro Prado's user avatar
3 votes
0 answers
67 views

C60 Fullerene Polymers?

Upon scouring Wikipedia for info about fullerenes to research, I came across this paragraph in the page on Buckminsterfullerene (C60): Under high pressure and temperature, repeated [2+2] ...
mpprogram6771's user avatar
3 votes
0 answers
103 views

Fluorescent polycarbonate changing optical qualities after melting

So I'm trying to figure out how to melt fluorescent poly without it changing. What it's doing after it's melted, under UV it's fluorescing a sort of opaque white instead of it's original color. Keep ...
Jared's user avatar
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3 votes
0 answers
1k views

What does it mean "polyester doesn't breathe"?

Often people say buy a cotton shirt because cotton "breathes" but polyester doesn't. (i.e. it makes you hot sweaty). What is the scientific meaning behind this? How does polyester trap the heat more ...
zooby's user avatar
  • 175
3 votes
0 answers
295 views

Is it possible to arrest the post-actinic effects of photodegradation in ABS polymers?

Polymers like acrylonitrile butadiene styrene (ABS) are adversely effected by UV exposure, both visually (by yellowing) and with regard to other material properties [1]. What's worse is that the ...
Edwin Steiner's user avatar
3 votes
0 answers
277 views

A surface with variable roughness

As you may know, wettability is a characteristic of each surface which determines what the contact angle would be when a droplet is put on the surface (see here for more info). Surface roughness has a ...
vorujak's user avatar
  • 367
3 votes
0 answers
387 views

Solvent for Norland Optical Adhesive

I'd like to know if there is any solvent that dissolves Norland Optical Adhesive 65 (and Rhodamine 6G), but does not dissolve PMMA that is used in e-beam lithography. I've tried acetone, methanol, ...
JeenV's user avatar
  • 31
3 votes
0 answers
363 views

PTFE (Teflon) combined with Silicon Polymers

I wanted to know if it would be possible to combine basic silicon polymers with PTFE in order to create a stable, non reactive silicon rubber that won't react to butane or other hydrocarbons in ...
Pierce's user avatar
  • 31
3 votes
1 answer
565 views

Polymerisation of methyl methacrylate - can the C=O group get involved?

When methyl methacrylate undergoes free radical addition polymerisation, the C=C pi bond is broken during the process: I'm wondering why the C=O pi bond doesn't get broken during the polymerisation. ...
PoH's user avatar
  • 467
3 votes
1 answer
111 views

Siiloxane polymer experiment

I believe the first reaction would be a substitution of $\ce{SiMe3}$ for $\ce{I}$ and creating $\ce{SiMe3Cl}$. The second process I think would involve the $\ce{Mg}$ removing the two $\ce{Cl}$ and ...
Alex's user avatar
  • 39
2 votes
0 answers
33 views

Small-Angle X-Ray Scattering of Bulk Polymers

Does anyone have any recommendations on how to get useful information from SAXS of polymers when the system is not dilute? This is the type of data we're working with: My understanding is that since ...
polythenesam's user avatar
2 votes
0 answers
174 views

How to dissolve paraformaldehyde in solvent without using water?

In the chloromethylation reaction of polysulfone (PSU), I am required to use paraformaldehyde and trimethylchlorosilane as the chloromethylating agent while stannic chloride as the catalyst. I ...
Majda Br's user avatar

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