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24

What you're specifically describing is typically known as UV degradation. The color change is due to the oxidation of the polymers that make up the plastic. These chemical reactions are demonstrated in satisfying detail here. Under the section titled "Photodegradation" is where you can find the intricacies of the polymer-oxidation process. And yes, such ...


23

When you rip, tear or mechanically deform a polymer (for example a piece of plastic) you are putting energy into the material. The energy from this deformation causes the polymer chains in the vicinity of the deformation to attempt to align. To some degree this partial alignment makes continued deformation easier. To continue tearing the polymer apart you ...


18

The process of forming an opaque area when you apply stress to a polymer film is known as crazing. Polymers are long chains and, when coated, often form tangled, amorphous, randomly aligned polymer regions. When stress is applied to the film, the stress can be relieved by the polymer chains aligning. In other words, energy introduced into the film by ...


17

Agreed: a physical action can cause a chemical reaction. For example, any attempt to manipulate $\ce{NI3}$ physically causes it to decompose (detonate). For that matter, dividing metals into tiny pieces changes chemical behavior, because bonds that would have been hidden in the interior are exposed at the surface. Finely divided iron, for example, becomes ...


14

There are all sorts of resources for picking the best gloves for handling any given type of chemical. This resource describes latex as being good for protecting against bases, alcohols, dilute water solutions, and fair against aldehydes, ketones. Indeed if you check the Glove Type and Chemical Use table towards the bottom of the page, you can see that latex ...


14

According to the Compendium of Polymer Terminology and Nomenclature (IUPAC Recommendations 2008, i.e. the ‘Purple Book’), three different types of names can be used for polymers: traditional names, structure-based names, and source-based names. When traditional names fit into the general pattern of systematic nomenclature, they are retained, in this case: ...


12

Without a sample and a gaschromatograph it is hard to say what exactly it can be but... there are at least three well-known sources of odour in plastics: Some residual of the monomer that makes up the plastic (that is a polymer). Some residual of some other substance used during the manufatcturing process (catalyzer, co-polymers, modifiers and so on). For ...


12

Most of the odor of cloves comes from volatile molecules, especially eugenol, found in the cloves. Eugenol is a water-immiscible, oily liquid at ambient temperatures. Plastic with resin identifiction code #6 is polystyrene. Polystyrene is not compatible with most organic solvents, because it tends to be softened, swelled, or even completely dissolved by ...


12

Polyethylene is prepared by polymerizing ethylene. Ethylene has a double bond, thanks to which the polymerization goes on. You could not do that with a methylene group. So the name comes after the smallest unit which is actually used to prepare the polymer.


11

This depends on type of plastic. You definitely can if plastic is perfluoropolyetylene (Teflon). You probably can if plastic is polyethylene or polypropylene, but both will degrade in long term (polypropylene will do it faster). You should not, if plastic is PET or other polyester, or polystyrene. It is probably most reliable to find which plastic you ...


10

@Philipp already mentioned microscopic cracks. This is called crazing. When a plastic is stretched, the extra space is filled randomly/irregularly. The gap between two polymer chains will grow, but most chains won't break. Also, if the material is already crystallized locally, the crystals will pull apart. As the overall structure is non-crystalline, the ...


9

The primary dangers from plastics themselves come when the monomer, and any compound put in to make the polymer matrix flexible, separate from the polymer and are released (leached) into whatever the plastic is containing. There are several such compounds which are known to be problematic to human biochemistry: Phthalates - These are aromatic diesters, with ...


9

It depends on the acid. I would recommend Neoprene gloves instead of latex gloves. I did this excerpt from this guide that I think is taken from the website that ringo mentioned: VG= Very Good G= Good F=Fair P=Poor Acetic acid VG Chromic Acid (50%) P Citric acid (10%) VG Hydrochloric acid G Hydrofluoric acid (48%) G Lactic acid (85%) VG Lauric acid (36%...


9

That should pose no issue regarding the glass Without images to see how unevenly you will apply the heat, I have to modify my instinctual reaction "That cannot possibly be an issue" to "Most likely it will be OK". I'd be much more worried about variation in the distilling if you are at some point drawing a distillate. If you cannot control the heat flux, ...


9

The first answer is great and the borosilicate glass can indeed survive harsh conditions. Here I'd like to suggest a DIY-project to improve the efficiency of the heater and make the column be warmed more evenly. Take a sheet of fiberglass cloth, sew the heating element in a serpentine pattern with the fiberglass threads, then wrap the crafted heating mantle ...


7

Most plastics consist of linear molecules with little inter-molecular interactions, so most plastics melts too easy. The only ones you mentioned having a chance are polyuretanes and polyamides. They have (CO)(NH) fragments, that forms strong intermolecular hydrogen bonds. So, they are ones of the strongest polymeric materials And I will recommend aluminum ...


7

No. Just because the polymer is of one or the other kind does not let you say what industrial process actually synthesized it. Subsequently it is impossible to know what trace chemicals are left in the polymer packaging. If if isn't labelled as microwave-safe, it isn't! They test the package for it's microwave compatibility, not one type of polymer each! ...


7

HDPE has a molecular weight more than several hundreds of thousands, "leaking" is plainly impossible. This taste is the tase of stale water, nobody knows what that taste is actually. Maybe its just the taste of not cold enough water, lacking some dissolved air, or some bacteriae develop after contact with air and light. (google for pseudomonas) The ...


7

What happens depends whether it is being heated in the presence or absence of oxygen. For example, in the manufacture of coke (mostly carbon), coal is heated without oxygen and from Coke Production For Blast Furnace Ironmaking: The coal-to-coke transformation takes place as follows: The heat is transferred from the heated brick walls into the coal charge....


7

Acetone is quite good at dissolving polymers. Do not use acetone on plastic before checking out whether that plastic can withstand acetone. Let it dry for a couple hours. Try turning it on again. If it does turn on, good. If not, you're pretty much screwed. However from what I can see from the picture you didn't really damage anything vital. You can try ...


6

PER is essentially PVC which has been plasticized and stabilized with acetyl tributyl citrate, instead of the host of phthalate-based plasticizers such as bis-diethylhexyl phthalate (DEHP) whose endocrine-disrupting properties give PVC its well-deserved bad reputation. Citrate salts tend to be readily water soluble, and therefore this material is touted to ...


6

No plastic of any practically useful thickness$^\dagger$ has $80\%$ transparency down to $200~\mathrm{nm}$. Period. Below is a UV transmission chart for various materials from a marketing brochure published by BrandTech, a manufacturer of disposable UV/Vis cuvettes (click image to enlarge): The chart only goes down to $210~\mathrm{nm}$; extrapolating the ...


5

There are many techniques for metal-coated polymers, as linked by permeakra Generally, vacuum deposition is an issue because the metal is hot. Cold deposition techniques (e.g., sputtering, ink coating) often work better. Common, commercially-available materials include: Pyralux - copper-coated polyimide from DuPont. Mylar - DuPont's name for biaxially-...


5

I have found an old paper that might answer your question, which is: "The Effect of Molecular Weight Distribution on Polyethylene Film Properties" P. J. Perrono, P. B. Lederman, Polymer Egineering and Science, 1972, 12, 5, 340-345 (DOI: 10.1002/pen.760120505). The properties of polyethylene evaluated in this paper as a function of the molecular weight ...


5

Mercury doesn't react with PET under normal conditions, but mercury vapor will diffuse into plastics. The diffusion will change the optical density of the plastic in the area where diffusion occurred. Here's a link to a nice study where the mercury was doped with a radioactive isotope of mercury. This doped mercury was placed in a glass chamber which ...


5

According to chemical resistance of plexiglass acrylic alcohol is not as aggressive as you mention with plexiglass acrylic. But, we have to signal that acrylics is a big family of polymers (thermoplastics or thermosets) derived from acrylic acid, methacrylic acid or other related compounds. Plexiglass is only a member of this family. Any way, in response to ...


5

If a solvent causes an amorphous polymer to craze, this is because the polymer is principally soluble in it. It diffuses into the surface, but without instantly dissolving it, as the polymer chains are still stuck in the glassy network of the substrate. The polymer swells (like a fruit gum in water), but the volume increase can only happen perpendicular to ...


5

When plastic sheets are produced, they are rapidly cooled to keep the polymer chains oriented in a way that makes the sheets nice and flat. This is a relatively high-strain orientation since it is associated with the energy level of the molecules at the casting temperature. Once the plastic is heated above its glass transition temperature, the polymer ...


5

My lab has a lot of experience with ITO-coated PET, but unfortunately I don't think anyone's tried etching it. We typically etch ITO-coated glass with a mixture of hydrochloric acid/water/nitric acid (4:2:1 by volume) which is fairly fast at room temperature, going through a few µm in about 10 minutes and mask with a positive photoresist. To your questions: ...


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