Questions tagged [polymers]

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

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1answer
112 views

Are there any organic compounds with three or more oxygen atoms bonded together in a straight chain?

Recently, there was a question which enquired about some oxygen rich compounds that burn themselves completely and thus not requiring any external atmospheric oxygen. The author came up with the ...
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19 views

How can I make Polyurea coating ( or equivalent) at home using Nature and the Supermarket?

Is there any DIY way to make my own polyurea coating using nature and supermarket products that I can paint my houseboat with?( it will all be painted, transparent, and the boathouse will be in salt ...
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35 views

Does lithium grease damage plastics such as ABS & PBT?

I have read that petroleum-based greases damage plastics due to the petroleum-derived nature of most plastics. However, I have seen lithium grease being used in electronics such as the gears in CD ...
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3answers
210 views

Orientation of amide bonds in a simplified polypeptide drawing

The syllabus for my course requires I draw protein polymers like this, where the patterned boxes represent different bodies (note that this is an extremely simplified drawing stripped down to its bare ...
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1answer
31 views

Inhibitors of hydration

Superglue (Cyanoacrylate) polymerizes via hydration, and using an activator such as a borax solution speeds up that process. I need to mix these 2 without them reacting. (Or at least not noticeably.) ...
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0answers
22 views

What is the chemical and physical process that results in a more homogeneous network in step-growth polymerization?

One of the advantage of chain-growth polymerisation over step-growth polimearisation (see section too in the reference) is that the latter results in more homogeneous polymer networks. The main ...
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0answers
26 views

Toughening of PMMA

For an experimental design with UV-activation I have moulded some UV-transparant (from ~250 nm up) PMMA sheets that I then cut and drill to my final mould. As expected, the PMMA sheets fracture easily ...
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1answer
33 views

Can large, sticky, sodium polyacrylate crystals be coated in a powder to facilitate handling?

I am separating a larger container of sodium polyacrylate crystals into smaller containers for student experiments. Commonly known as "Deco Cubes" and used by florists in decorations and ...
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0answers
88 views

Is this plastic clip made of polypropylene or polyethylene?

I am trying to re-attach an automotive clip (painted plastic with a yellow (epoxy?) hard adhesive backing) which secures a trim piece back onto the vehicle's roof sheet metal (unpainted (primed?) area)...
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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 ...
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30 views

What is the difference between PEF and PTF bioplastics?

I am trying to research single use plastics replacements, and wanted to explain how PEF and PTF are a good choice. Although as I am researching I can't find clear information about them, also how they ...
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20 views

HDPE production free radicals

I know that LDPE is produced by addition polymerization, where the free radical is peroxide or some other radical oxygen species. This isn't part of the product we want but also isn't a catalyst, ...
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1answer
59 views

Optimal lipophilic solvent for washing PEEK-lined reversed-phase HPLC columns

What would be the reasonable strategy for washing a reversed-phase (RP) octadecylsilyl (ODS) C18 HPLC columns from lipids and other non-polar residues? The columns are used for biochemical analysis of ...
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1answer
57 views

The relationship of the osmotic pressure of a polymeric solution and its the molecular mass

Why is the osmotic pressure of a polymeric solution decreases when the molecular mass is increasing? I am honestly unsure if the above statement is true, at least it seems to me to be true. When I ...
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1answer
46 views

Is each bag of plastic a polymer/macromolecule? If yes, why does it tear so easily? [duplicate]

For example, polyethene is a macromolecule. So each bag of polyethene should be one molecule. Doesn't tearing it therefore involve breaking strong covalent bonds? Shouldn't the energy needed to do ...
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0answers
38 views

Hazards of eating non-stick coating, particularly considering the coating primer [closed]

How unhealthy are teflon / non-stick coating chips that end up eaten? What role does the primer coating play? Existing similar threads that don't go into enough detail: 1, 2 I understand that there is ...
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1answer
89 views

How Does Differential Scanning Calorimetry (DSC) Differentiate Between Exothermic and Endothermic Changes?

In DSC, heat flux difference between sample and reference is measured as function of temperature while temperature of sample and reference are maintained the same. DSC is often used for polymer ...
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17 views

What allows for colloidal solutions of polymers to act like solutions despite the large size of polymers?

I have been introduced to a paragraph in my textbook that I am trying to understand. Macromolecular colloids: Macromolecules in suitable solvents form solutions in which the size of the ...
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1answer
1k views

What causes plastic to become brittle and can it be softened again?

I have some old computer case parts made of ABS plastic. Two decades of storage has embrittled the plastic to the point where they easily crack or shatter with the slightest bend. What is going on ...
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40 views

Calculation of Repeating units in polymer

Assume that I want to react A with repeating units of the polymer with ratio of 1:1. That is, I want to calculate that if I have $M_A$ mol of A, then what grams of polymer will I need to afford $M_A$ ...
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1answer
64 views

Chain transfer in polystyrene synthesis

while I was studying the many side reactions of radical polymerization, I stumbled across this source which illustrates the chain transfer side reaction in polystyrene synthesis: Of course, there is ...
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1answer
104 views

Identifying the solubility of Polyvinyl Alcohol (PVA) in water versus temperature

Background: Poly Vinyl Alchohol (PVA) is a plastic used for a sacrificial support material for 3D printing and sewing. This material is used specifically because it is water soluble, and can be ...
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24 views

Size Exclusion Cromatography - How Does Detector Determine Molecular Mass Distribution in Polymers?

In materials I am using it is written that detectors in SE cromatography determine concentration of polymer molecules of particular mass on exit of column by measuring index of refraction. How is ...
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0answers
43 views

Nova 2.1 stop command (graphical user interface for electrochemical measurement)

We are doing an electrochemical polymerization of a semiconducting polymer and would like to try it as a pulsed square wave with defined frequency (i.e. 100 Hz) and duty cycle (i.e. 50%), but fixing a ...
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1answer
35 views

How does addition of side chains affect solubility and processibility of polyphenylene vinylene?

I am studying electrical engineering and physics. In a recent lecture I was told the $\ce{OC1C10}\text{-PPV}$ molecule has the chains added to the oxygen atom down below because it allows for ...
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1answer
104 views

Why is Nylon-2,6 biodegradable but Nylon-6,6 isn't?

Both have similar functional groups so what causes Nylon 2,6 to be biodegradable while Nylon 6,6 is not?
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0answers
135 views

What gives natural rubber a permanent shiny finishing?

Natural rubber is made by vulcanizing latex mixed with sulphur. Commonly, the resulting natural rubber is dull instead of shiny. However, there are also products made out of natural rubber that are ...
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60 views

How to remove starch from silicone ("Oogoo")?

Oogoo is an easy and cheap way of creating silicone rubber objects from a hand-formable putty. Basically: just mix silicone caulk with starch (I'm using acetate moisture absorbing silicone caulking ...
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0answers
24 views

Can Chlorhexidine Gluconate (CHG) be used for disinfection of medical device (e.g. of polyethylene material)? [closed]

Chlorhexidine is commonly used as a skin antiseptic, hand disinfectant, endodontic irrigant etc. It possess antibacterial and antifungal properties, and is considered low toxicity when used in low ...
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1answer
30 views

How can I calculate the distances between residues of a protein? [closed]

Suppose, we have a protein (16PK). We are considering a 5-residue segment/window. If we assume ASN10 to be the ...
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0answers
49 views

Why are glyosidic linkage of glucose and fructose rings often occurring at the 1' and 4' prime positions?

Here are some example combinations from my textbook: In all of these combined products, the reactive centres seem to be the carbon at first position/ fourth position from the oxygen in priority. Is ...
3
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1answer
288 views

Why does polymerisation of n glycine molecules give n water molecules?

Referring to this webpage, Condensation polymerisation of glycine A simple counting argument would tell us that: 2 glycine molecules react, releasing 1 water molecule 3 glycine molecules react, ...
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1answer
87 views

What is the difference between structure and morphology in polymer blends?

When talking about polymer blends there is a difference between its structure and morphology, but I am not sure what it is. These two terms are used interchangeably in materials I use to study, but I ...
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102 views

Does (BeCl2)n have 3c - 4e- 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 $...
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34 views

Does a UVC transparent polymer exist or can it be made? [closed]

Does a UVC transparent polymer exist or can it be made? I am trying to find a polymer that can transmit UVC light. Most materials absorb this 265 265 nm range. for example quartz passes UVC but glass ...
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1answer
26 views

Humidity diffusion in Silicone Elastomer and effects on refraction / transmissivity

There is an issue I'm facing that is very tricky. A solar cell that is encapsulated in Sylgard 184 Silicone Elastomer with a front borofloat front glass. This cell is used to measure a light intensity....
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0answers
24 views

Is there a way to experimentally determine if a copolymer has a random monomer distribution or a blocky monomer distribution?

I prepared a styrene-butadiene copolymer with a polar modifier. The expectation is that the copolymer is "random". Is there a way to confirm this using standard characterization techniques?
2
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1answer
60 views

Making bioplastic at high school level chemistry using PLA/Starch blends

I'm currently working on a high school chemistry essay about biodegradable plastics. I know that there is an easy way to synthesize Thermoplastic Starch (TPS), a starch-based bioplastic using glycerol ...
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0answers
62 views

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 ...
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31 views

How to know what lubricant is compatible with resin matrix

I am reading a lot of papers on electrically conductive adhesives that say that the filler (flake) is coated with lubricant which needs to be “compatible” with the epoxy resin matrix to have good ...
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0answers
15 views

Making a metal oil paint by the use of unsaturated polyester resin

How can we make metal coating or oil paint by the use of unsaturated polyester resin and its suitable solvent, plus some pigments only if really required?
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0answers
32 views

Are ekaconjugated polymers used as dielectrics? If not, why so?

So I came across an article called "Giant polarization in high polymers" and I was wondering if there was a reason why these types of polymers haven't found use in capacitors at this point. ...
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1answer
73 views

The color of resorcinol-formaldehyde resin

At school, I did an experiment of synthesizing resorcinol-formaldehyde resin. When I added $\ce{NaOH}$ and gave some heat, the color of resorcinol-formaldehyde resin inside the test tube became ...
3
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1answer
90 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 ...
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0answers
26 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 ...
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0answers
53 views

Absorption spectrum of common plastic polymers

I am looking for data regarding absorption spectrum of common used plastic polymers, in the range of 200- 1.000 nm Moreover, I am looking for inorganic or organic compounds, which can be mixed ...
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0answers
55 views

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 ...
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0answers
31 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 ...
4
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1answer
199 views

Mechanism of formaldehyde / phenol condensation

The production of bakelite using this method, but with an acid as the catalyst is simple enough; a protonation of the carbonyl oxygen, followed by an electrophilic substitution to the ring. The ...
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1answer
50 views

Hair styling gels and 'liquid gels' - effect of formulation / composition on viscosity and performance [closed]

[Disclaimer: I am aware that this is a very 'first-world problem', 'light-hearted' kind of question, given the health crisis we are still going through. Just to avoid offending anyone, here's an easy ...

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