Questions tagged [polymers]

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

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Why upon melting of PEO between crossed polars colours appear?

Crystalline PEO when under crossed polars shows distinct Maltese cross pattern. Being birefringent, when polymer crystal align with the polarizer or analyser it shows extinction regions (effect known ...
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Copolymerization regioselectivity

When undergoing copolymerization via free radical mechanism Buna-N forms a certain way. Actual product and possible products Can we predict which of the products will be formed based on the ...
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Predicting If a Polymer is homopolymer or copolymer? [closed]

Just by looking at the structure of the polymer (assuming that you are seeing the structure for first time),is it a way one can find if the given polymer is a homopolymer or a copolymer.
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Difference between Ziegler–Natta method and Phillips method [closed]

I have to compare the similarities and differences between the Zieglerr–Natta method and Phillips method of producing polyethylene. However, the only difference I can find is the difference in ...
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44 views

Why polyethylene (PE), wool (polyamide) and cotton (cellulose) burnt with different smells, while they just product CO2 (and N2)?

Both PE and cotton produce CO2, but they distinctly have different smells while being burnt (Burning PE has smell of candle wax, while burning cotton’s smell is like burning leaves). Wool produces CO2 ...
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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 ...
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54 views

What does bulk mean when talking about polymers? [closed]

I recently read a paper by Lyulin et al. [1] where they talk about thin films and bulk polymers, I just don't quite understand what they mean by "bulk". Can someone please explain? References ...
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1answer
62 views

Polystyrene properties after dissolved by acetone

Polystyrene plastic can be dissolved in acetone. I would like to understand: If the dissolved polystyrene will take-out of the acetone and becomes solid again (after all the acetone evaporates), will ...
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Cyclohexane as a Solvent

I was wondering, why is cyclohexane used as a solvent in the synthesis of nylon. Typically, I see it being used to dissolved adipose chloride, but why is this the case?
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Super-absorbent Polymers [closed]

I want to cast a cube out of super-absorbent powder (Fake Snow) for an art piece, and make it become shapeless by gradually exposing it to water over 7 days. I have 2 questions: What is the best type ...
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How to get rid needle clogging on electrospinning of PLA/PCL/PMMA/Collagen?

For my thesis research, I dissolved PLA and PCL in chloroform: methanol (3:1), PMMA (350.000 MW, 13 wt%) in acetone, and collagen in acetate acid--and then, I mixed them together. The problem is when ...
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Liquid alternative to alcohol to lower density of water

I am trying to create a suspension of polypropylene particles in a water based liquid. I want the density of the liquid to be more than or equal to the density of polypropylene (855 - 946 kg/m3) so ...
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How to dissolve PLA/PCL/PMMA?

I have a research about electrospun membrane synthesis where I dissolve PLA pellets in chloroform:methanol (3:1) for 3 hours and also PCL pellets in chloroform:methanol (3:1) for 3 hours too. Another ...
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1answer
99 views

Is it possible to have an allotrope of carbon as a long unbranched chain of itself?

Is it possible to have an allotrope of carbon with formula $\ce{(=C=)_n}$? Well, let's actually leave alone the separate question like from which "monomer" would one produce such a thing (can one ...
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Calculate the degree of polymerisation. It's molecular weight and its repeat structure are given

I understand how to calculate the degree of polymerisation normally, but in this question, the extra H and OH outside the bracketed monomer have thrown me off. Do I include their atomic masses in the ...
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what are the cons of converting plastic to fuel

I have been trying to read how to fix plastic problems, there seems to be 3 outstanding solutions Re-use Recycle Decompose to Fuel Recycling is expensive, requires lots of water and the quality ...
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How to remove the foggy discoloration in polycarbonate tubes caused by acetone?

Unknowing that the tubes used in the centrifuge are made of polycarbonate, I cleaned them with acetone. Following, a white smoky discolouration appeared and the tubes turned opaque. Is there any way ...
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How can I explain PEO-b-PLA behaviors in dissolution?

I dissolved PEO 10K - PLLA 14K in toluene at the concentration of $\pu{50 mg/ml}$, $\pu{25 mg/ml}$, and $\pu{5 mg/ml}$ including $\pu{30 min}$ of sonication. When I sonicated them at room temperature,...
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Will acetone dissolve the structure of Spandex?

We are trying to remove rubber from spandex, it's been super-glued on. We know that acetone will dissolve superglue, but we're unsure if acetone will harm Spandex. Anyone that can help us, your input ...
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Can common refrigerants be chemically converted into something that is a stable solid at STP? [closed]

I've been thinking how refrigerants - which are highly potent greenhouse gases (hundreds and even thousands of times more potent than CO2) - are likely to be vented to atmosphere eventually either due ...
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1answer
85 views

What are glues/adhesives for cardboard boxes/crates made of?

Open cardboard boxes/crates, often for foodstuffs, are often glued to hold their shape. What is the glue/adhesive made of? I ask to know if it is biodegradable, such that it is suitable for ...
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What materials reversibly swell up slightly when in a moist environment?

I am aware that some "Super Absorbent Polymers" can swell up enormously when they absorb water. However, I am looking for a material which swells up (maybe about 30% to 100%) when in a moist ...
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Would the mixture of Latex Rubber and the Squid's chitin make a biodegradable plastic?

I don't know much of Chemistry but I put the chemical structures of each. Thank you!
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What makes polyimides good polymers for fibers?

Wikipedia says polyimides are known for “thermal stability, good chemical resistance, excellent mechanical properties”. I guess that's why they're used industrially as fibers. But where do they ...
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What is it mean by Grade in thermoplastics?

I have seen some thermoplastics of the same type categorized by its grade .. What does it mean by that? What does it means the word grade in this context? Is it just a name for slightly differences ...
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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 ...
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How good is 2-Butoxyethanol as a replacement for acetone?

I have recently bought a bottle of acetone from my local hardware store. When I opened the bottle, I was surprised about the absence of the strong smell of acetone. Only then I discovered the smaller ...
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1answer
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Catalysts to accelerate foamy polyurethane reaction

This is the reaction that I am referring to: https://www.youtube.com/watch?v=EoRUSo0BWC0 I am interested in finding catalysts to accelerate this fun chemistry demonstration. I have heard that some ...
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1answer
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Distribution of polymer lengths

Suppose we have a chemical reaction where a linear chain can form (reversibly) from building blocks (e.g. atoms or molecules): $$\ce{X_$i$ + X_$k$ <=>[$k_\mathrm{fwd}$][$k_\mathrm{rev}$] X_$i$...
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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,...
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311 views

What polymer can be dissolved in ethanol and is insoluble in water?

I need a polymer with parameters noted above. How to determine the solubility theoretically? Hansen/Hildebrand solubility parameters? Wypych is not the ultimate solution...
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Why are my microgels not centrifuging (sticking to tube)?

I have created a hydrogel water in oil emulsion using a microfluidic flow focusing device. I have been able to collect the microgels/particles from the device and then pipette/manipulate them. When I ...
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Will lead bind to dissolved polymer (Kapton) monomers?

We are attempting to determine the concentration of lead impurities in Kapton. Essentially we need to extract lead in the tape polymer Kapton (structure seen below); The amount of lead in the tape is ...
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What is the difference between radii of Gyration and hydrodynamic radii of a polymer? [closed]

Why do you consider that the relationship between RH and RG should depend on the quality of the solvent?
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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 ...
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1answer
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Does melting HDPE plastic produce toxic fumes? (melting, not burning)

● The question isn't about burning HDPE but melting it at the proper temperature. (At 120 to 180°C depending on it's density, it becomes gooey. According to the source below the "extrusion" ...
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1answer
251 views

What would happen if I combined this polymer and this metal (assuming I can) [closed]

So let me explain, I recently found out about a material called sorbothane (which is a polymer). Now, sorbothane is special because not only does it highly efficiently absorb shock, but also highly ...
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Why isn't nylon as strong as kevlar?

Why is Kevlar stronger than nylon? They both contain Hydrogen bonding and should have equal strength but this is not the case instead Kevlar is fire resistant. What makes it stronger. Greater hydrogen ...
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Which Flocculant/Coagulant is ideal for harvesting Algae?

While dealing with Algae fit for human consumption (as protein supplements), which is the most suitable coagulant/Flocculant available? Factors to consider: 1) Cost Effectiveness (for instance poly ...
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What does the slash in polymer nomenclature, e.g. Acrylates/ Beheneth-25 Methacrylate Copolymer, mean?

I was given a task to find SDS-Sheets for polymers/microplastic particles in cosmetics and I am confused, since there are often two chemicals divided by "/", e.g. Acrylates/ Beheneth-25 Methacrylate ...
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Can amorphous polymers have a melting temperature as well as their glass transition transition temperature?

Above the Tg, amorphous polymers are described as viscous liquids. What then would they be likened to above their melting point, should they have one?
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Why can't a thermosetting plastic be stretched like an elastomer?

So far I've learnt that there are 2 'types' of thermosets: thermosetting plastics and thermosetting elastomers. Both of them consists of crosslinks that when stretched, allows for the material to ...
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what is the material used to detect the presence of free radicals in the reaction?

To detect the presence of free radicals in the reaction usually, acrylonitrile used but this material is not available in my university. Is there another material used to detect the presence of free ...
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explanation of why interphase occurs in polymers

Im new to chemistry network of stackexchange so please be kind to me! I heard that interphase is created in clay polymer for 2 reasons. one of the reasons is the insoluble part of the polymer and the ...
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1answer
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Is temperature of crystallisation same as melting point temperature for polymers?

Melting point tends to be a temperature range. Is it true that the temperature of crystallisation is the highest temperature at which the polymer melts and thus there is some distinction between ...
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Why isn’t there LDPP, HDPP?

Unlike polyethylene that there are LDPE, HDPE, or LLDPE, when it comes to polypropylene the issue becomes about copolymer (homo/ copo/ block copolymer) or location of methyl group (isotactic/ atactic/ ...
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378 views

Finding the repeating unit of polymerisation given two constituent molecules

The compounds $\ce{H2NCH2CH2NH2}$ and $\ce{HOOCCH2COOH}$ react to form a polymer. What is the structure of the repeating unit of the polymer? A. $\require{enclose}\ce{\enclose{horizontalstrike}{(}...
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596 views

Does propylene glycol dissolve plastic?

According to Médecins Sans Frontières propylene glycol can dissolve plastic: As propylene glycol can dissolve plastic... (Source). Is this claim true? This seems rather spurious to me. If it ...
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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 ...