Questions tagged [plastics]

For questions relating to the structures, properties, production methods and potential hazards of polymer materials commonly known as plastics

Filter by
Sorted by
Tagged with
3
votes
0answers
36 views

Coating applied to plastic (polymer suitable for straws) to repel carbon dioxide to prevent "floating"

We are four students currently finalizing our last exam-project before our bachelor. We confirmed our hypothesis that straws floating to the top of your drink is a "problem" from our survey. Our ...
2
votes
0answers
101 views

How does dissolving LDPE in wax work?

I was looking into machinable wax, and found it's based on dissolving LDPE into melted wax. While I understand the normal salt dissolving in water process, I'm not really sure how plastics can ...
2
votes
0answers
43 views

Do Pigments, Dyes (with plastics) or Plastic Itself Exist that Appear White but are NIR transparent?

I am looking to make a NIR (Near Infrared) window for a project I am working on but need it to appear white rather than the typical Reddish Black NIR window found on most remotes. Does a dye or ...
1
vote
0answers
680 views

Acrylic paint on polypropylene PP

I have bought a set of polypropylene (PP) test tubes that I wish to paint with acrylic to achieve the same effect as the following image: Can anyone recommend a process I can apply to the test tubes (...
0
votes
2answers
119 views

Which is stronger, PET or PVC? [closed]

I have been given the task of designing a new wheel rim (the metal part of the wheel) but instead of metal, it has to be made out of a polymer. I'm thinking of using either PVC or PET but I don't ...
3
votes
0answers
44 views

Why don't you see rigid PET extrusions?

So, I'm confused about something. Rigid plastic extrusions for outdoor applications, such as twinwall greenhouse panels and the like, are most commonly polycarbonate. They're next most common ...
1
vote
1answer
54 views

Polysytrene factories and hypothetical health concerns [closed]

Background/Research so far I'm actually not much of a chemist at all; but I'm doing research for a book I'm writing. The events of the story begin from a factory that produces/supplies jewel cases ...
3
votes
2answers
885 views

What is the name of the crinkly plastic used in clear parts of envelopes?

I've always wondered what it is, as it makes a lot of noise on being deformed. No other common plastic that I've come across has quite the same properties.
4
votes
1answer
2k views

Etching ITO on PET without damage

I am planning to use some of this to construct a transparent touch panel for a prototype of mine. It is PET plastic coated in Indium Tin Oxide. My plan is as follows: Use some of this UV-cure dry ...
2
votes
2answers
5k views

What is inhibiting polystyrene's ability to dissolve in traditional solvents like ethanol or acetone?

My friend and I have been struggling with this problem for a couple days. Because polystyrene has a similar structure to many plastics, we assumed that it would dissolve in acetone. However, after ...
1
vote
0answers
192 views

Does the plastic cup PETE 1 material leak toxic material if subject to boiling water even for part of a minute?

Sometimes a cafe may pour boiling tea into a plastic cup made of PETE 1 and then add lemon and cold water / ice to it. When the cup is handed to the customer, the cup looks ok. And I suppose even if ...
2
votes
1answer
296 views

Supermarket HDPE plastic bags safety

Supermarket plastic bags are made of high density polyethylene, and I am interested in the decomposition products at high temperature: what type of compounds are released and how dangerous are they? I ...
4
votes
1answer
1k views

Why does plastic tear easier when you pull it quickly?

If you've ever taken the plastic from a plastic bag and pulled on it, you might know what I mean. If you pull quickly, the plastic tears relatively easily, but if you pull it slowly, it gets stretched ...
1
vote
1answer
61 views

Hazards of Keeping Freshwater Fish in a Container that was Used for Adipic Acid

I have an Intermediate Bulk Container (IBC) which is a large 3' x 3'x 3' plastic cube. The label on the container described it as storing Adipic Acid. Is it safe to use this container to grow plant ...
5
votes
3answers
3k views

Why plastic sheets contract when heated?

Why do thin plastic sheets contract when heated, contradictory to the behavior of most other materials ? What are the things going on at the molecular level ?
1
vote
0answers
208 views

Diffusion into PMMA

My thesis is about effect of cigarette smoke to PMMA polymer, apparently cigarette smoke have some amount of eugenol which is mildly acidic and they will evaporate when the cigarette is burned. In ...
4
votes
1answer
206 views

At what temperature do complex hydrocarbons become ashes?

When heating a metal tube with polypropelene in it, i found that i still had brittle black foam and flakes in it even though it had been in a blue flame at around 500'C What happens to complex ...
3
votes
1answer
375 views

What's causing my plastic fork to break?

This has been a real mystery for me at work. For the past three days I've eaten salads for lunch. I used a plastic bowl with a lid and when I was finished with the salad, I didn't rinse out the bowl ...
3
votes
1answer
91 views

Biodegradation time for biodegradable shopping bags?

How long does it take for the plastic/polythene shopping bags marked biodegradable to biodegrade?
3
votes
1answer
541 views

Urea-Formaldehyde cleanup

I work a lot with Urea-Formaldehyde resin/plastic, both in carpentry and textiles. Cleanup while still uncured is simple enough. Cleanup before even mixed is easy enough. What I don't know, is how to ...
4
votes
1answer
1k views

What is a food-safe level of exposure of plastic containers to heat?

There are many articles about how heat can trigger the release of potentially harmful carcinogens from plastic containers into the food or liquid they contain. Specifics they fail to mention, though, ...
2
votes
1answer
11k views

What is the transparent film that covers water-soluble dishwasher tablets?

These dishwasher tablets (Finish Powerball Shine) seem to be covered in plastic! But that can't possibly be true since there's no unwrapping, and they're completely soluble in water. What is the ...
0
votes
1answer
188 views

Do melt flow rate and density tell you everything about pure HDPE?

I understand that melt flow rate and density can be used to classify HDPE. Does this mean that if I have the melt flow rate and density of an HDPE (with no additives), then I can know its other ...
4
votes
2answers
3k views

Plastic membrane that lets water in from the outside only?

I'm looking for a type of plastic membrane that would let water through it from the outside, but wouldn't allow water to escape once it's inside the membrane. Ideally available in a roll. Does such ...
4
votes
1answer
7k views

How does the catalyst in a polyester resin or epoxy work?

I would like to understand how the polyester resin or epoxy catalyst works and to what degree it must be mixed with the base material in order to be effective. Typical product instructions advise to ...
3
votes
3answers
2k views

Can Polyethylene Dissolve on 50-60 °C

I know that polyethylene's melting point is between 115–135 °C, however I would like to know if can it start dissolving between 50-60 °C? In a real example, if I put warm food (straight from the ...
4
votes
1answer
64 views

Are there softeners in synthetic materials?

Are there softeners used in polyester or polypropylene to make these materials more flexible? Or is this not needed for this kind of synthesis?
3
votes
1answer
586 views

Polyurethane epoxy resin chemistry advice please?

My friend can buy polyurethane epoxy from his workplace for 3 dollars a litre, except that he doesn't know precisely the data sheet for it. His factory gets it in 20 ton deliveries. He says that the ...
28
votes
2answers
3k views

Ripping apart plastic: is this a chemical or physical change?

I was holding a piece of plastic earlier, and I ripped it in half. This caused me to start to think about what was happening at the atomic level. If the plastic is being ripped, clearly bonds are ...
3
votes
1answer
2k views

Which plastic type is used inside dishwashers?

We have a drinking bottle made partly from polypropylene that wraps when washed in a dishwasher. We would like to change the plastic type so that it can withstand in dishwasher. I know for a fact ...
10
votes
1answer
6k views

How do cloves break down plastic?

When my family buys powdered cloves in bulk, we put them in plastic until we get home - which takes at very most an hour. As soon as we get home, we transfer them into glass because we have had issues ...
13
votes
3answers
31k views

Why does alcohol crack acrylic (plexiglass)?

I have seen videos and discussions about alcohol cracking acrylic, and waterblock manufacturers reminding users to not use alcohol in cooling systems with plexiglass acrylic, but why is this so? The ...
2
votes
1answer
410 views

Thermal decomposition products of polyurea?

Are the thermal decomposition products of polyurea polymers known, especially of the urea group, in the absence of water? Looking at the formula ...
3
votes
0answers
338 views

Chemistry of Stripper Poles: How much weight can different materials support? [closed]

I'm looking to create a light up dancing pole. This requires a translucent material that is strong enough to support the weight and force of a human being, even when it's hollowed out to so LEDs can ...
6
votes
3answers
3k views

Can plastic leak into water from a HDPE "2" plastic container at room temperature?

Here in USA supermarkets often sell water in plastic 1 gallon jugs. These jugs seem to all be stamped with the text "HDPE" (meaning that the material is High-density polyethylene) and a resin number ...
1
vote
0answers
104 views

Resin for making Jewelry

I want to make resin jewelry, but I'm having problems! I want to create that effect, but I do not know what materials to use The result is a mix of resin and other such things
1
vote
1answer
76 views

Which material to use for athletic accessories?

I'm looking for some guidance in selecting the right material for dance shoes heels and women's self-defense accessories. I'm looking for a material that 1) has a superb strength-to-weight ratio, can ...
3
votes
2answers
601 views

Material that doesn't melt at 800 deg F, but can be dissolved?

I'm a sculptor and I have a chemistry/plastic question. I thought here would be a good place to ask. I'm looking for a substance (probably a plastic) that has these characteristics: Doesn't melt at ...
4
votes
1answer
1k views

The walls of a plastic vial with Mercury inside are darkening. What is causing this?

I have a sample of Mercury in a plastic vial, The vial is a BD Vacutainer (genuine), made of polyethylene terephthalate. It is used for blood samples, and the one I used was new. When the vial was ...
17
votes
2answers
6k views

Why do many transparent plastics turn opaque when deformed?

Many transparent plastic materials, rigid or not, turn opaque (white) when subjected to stress, deformations or when folded (if not rigid) . The effect seems to be irreversible. What is the cause? ...
2
votes
1answer
138 views

Taiwan propylene explosions one week ago

Is it wrong way to use WATER to relieve the big disaster(propylene leak). What is a better way to relieve propylene leak in a street about large area? Any possible choice to prevent explosion?
5
votes
2answers
18k views

What is the plastic material of the CD cases?

What is the material of which the transparent part of CD cases are made of? It is nicely rigid and really lightweight.
2
votes
1answer
978 views

What is relationship between molecular weight distribution of PE and its strength?

I'm trying to figure out the relationship between the molecular weight distribution of a polyethylene plastic and its strength and heat sealability. (The molecular weight distribution is described ...
3
votes
1answer
777 views

What is this red substance that has accumulated at the bottom of a plastic bottle full of petrol (see picture)?

About two weeks ago I put some ordinary unleaded petrol into a plastic water bottle, as a temporary measure (long story, don't ask!). It has now formed a reddish liquid at the bottom of the bottle. ...
2
votes
2answers
275 views

What is Bisphenol A used for?

I am trying to find out what BPA is used for in the industrial production of plastics. On sources such as Wikipedia I only found the information that it is used, but not why. What are the advantages ...
8
votes
3answers
124k views

Are all PP(Polypropylene), i.e. resin code 5 plastics, safe for microwave and steaming?

If a plastic is marked PP as in Polypropylene (i.e. resin code 5), is it automatically safe for steaming and microwaving, such that it wouldn't leach chemicals into the food(besides not melting)?
2
votes
0answers
261 views

Can TBE electrophoresis buffer be stored in a PETE container?

I'm doing a science project on agarose gel electrophoresis and would like to know if it is safe to store Tris/Borate/EDTA buffer solution inside a PETE container since I will be making about 10L of ...
3
votes
1answer
5k views

Decomposition products of PET

On Wikipedia, it says that polyethylene terephthalate (PET) decomposes at temperatures above 350°C. What are these decomposition products? I read further that acetaldehyde is produced, but is that ...
4
votes
1answer
252 views

Plastics for food packaging

There are many types of plastics that can be used for food packaging, for example: Polyethylene terephthalate (PET) Polyethylene (PE) Polyvinyl chloride (PVC) Polypropylene (PP) What are the ...
4
votes
2answers
769 views

Biopolymers as alternative for PVC and PU?

I'm working on a project making a product line more sustainable, environmentally friendly and ready for recycling. Now I'm searching for good and suitable biopolymers for a part of the product that ...