What is Plastic: Definition and 288 Discussions

Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptability, plus a wide range of other properties, such as being lightweight, durable, flexible, and inexpensive to produce, has led to its widespread use. Plastics typically are made through human industrial systems. Most modern plastics are derived from fossil fuel-based chemicals like natural gas or petroleum; however, recent industrial methods use variants made from renewable materials, such as corn or cotton derivatives.In developed economies, about a third of plastic is used in packaging and roughly the same in buildings in applications such as piping, plumbing or vinyl siding. Other uses include automobiles (up to 20% plastic ), furniture, and toys. In the developing world, the applications of plastic may differ; 42% of India's consumption is used in packaging. In the medical field, polymer implants and other medical devices are derived at least partially from plastic. Worldwide, about 50 kg of plastic is produced annually per person, with production doubling every ten years.
The world's first fully synthetic plastic was Bakelite, invented in New York in 1907, by Leo Baekeland, who coined the term "plastics". Dozens of different types of plastics are produced today, such as polyethylene, which is widely used in product packaging, and polyvinyl chloride, used in construction and pipes because of its strength and durability. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger, who has been called "the father of polymer chemistry" and Herman Mark, known as "the father of polymer physics".The success and dominance of plastics starting in the early 20th century has caused widespread environmental problems, due to their slow decomposition rate in natural ecosystems. Toward the end of the 20th century, the plastics industry promoted recycling in order to assuage environmental concerns while continuing to produce virgin plastic. The main companies producing plastics doubted the economic viability of recycling at the time, and this is reflected in contemporary plastic collection. Plastic collection and recycling is largely ineffective because of the complexity of cleaning and sorting post-consumer plastics. Most plastic produced has not been reused, either being captured in landfills or persisting in the environment as plastic pollution. Plastic pollution can be found in all the world's major water bodies, for example, creating garbage patches in all of the world's oceans and contaminating terrestrial ecosystems.

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  1. C

    Will an Enzyme That Eats Plastic Solve Our Pollution Problem?

    Scientists have created a mutant enzyme that breaks down plastic drinks bottles – by accident. Do you think it will help? How fast it can be implemented worldwide?
  2. G

    Plastic particles found in bottled water

    So recently news broke about there being plastic particles/contaminants inside major brand water bottles (plastic), so since I don't drink bottles water but use some plastic bottles myself to fill in some fresh water from the local forest I then wonder how did the plastic particles got in the...
  3. Matthew Titus

    Calculating Elastic plastic bending moment

    1. The problem statement, all variables, and given/known data Good day I am preparing for a strength of materials exam and I can't seem to solve this problem. I am unsure if the section below the neutral axis is fully plastic before the edge of the flange experiences the yield stress. Could...
  4. kyphysics

    Study: Major Bottled Water Brands Contaminated w/ Plastic

    https://www.yahoo.com/lifestyle/top-bottled-water-brands-contaminated-plastic-particles-report-013209098.html What conclusions should we draw? I drink exclusively bottled water too. Can't remember last time I had it unbottled.
  5. A

    Can Plastic Exhibit Magnetism Under Certain Conditions?”

    I appreciate that under standard conditions small (c 5mm) plastic particles are apolar and thus non-magentic. However, can conditions be created under which such particles could exhibit polarity?
  6. K

    Transparent conductor on transparent plastic film?

    Need two transparent conductors in an arrangment like this on a transparent plastic film. Such as ITO on PET. But it doesn't have to be ITO necessarily. There are going to be much more fingers and size of the lanes and their gaps are going to be sub milimeter, so hand drawing is out of the...
  7. not_a_chemist

    Chemical Polymer Separation (PLA, ABS, HIPS, and PETG)

    Good day all! I've got a granular mixture of PLA, ABS, HIPS, and PETG with a particle size of about a quarter inch, and I'm trying to isolate each polymer from the mix. PLA and PETG have densities of about 1.27g/ml, and ABS and HIPS have densities of around 1.06g/ml. I think a weighted solution...
  8. C

    Quantifying Static Electricity Hazard with High Explosives

    In the making of firework explosives, the explosive mixtures are handled with great care to avoid static electricity induced detonation of the explosives. Is it a good idea that they store the explosives in a plastic container - isn't there a risk of static buildup that could detonate the...
  9. S

    Can't we just smelt plastic into igneous rocks?

    Now cost asides...can't we just smelt plastic into igneous rocks? I'm sure we can achieve the temperature & pressure to do it. Plastics Mainly Composed of C H O N Cl S. N H Cl are all trappable within rock layers. Additives like Si and Fe can be added in various steps of heating to form silica...
  10. A
  11. H

    Plastic Deformation: Power Law & Strain Hardening Exponents

    Is there any relation between power law exponent of of P-h curve and strain hardening exponent of stress-strain curve?
  12. T

    Can a plastic container break from having too much water

    I have a plastic container holding about 30 gallons of water, and it is bowing. Do I need to be concerned about it breaking?
  13. Liquito

    Heavy Duty Trolley Plastic Bending & Strain Energy

    Homework Statement http://imgur.com/a/RoKVR The link above have the full problem I mostly have issue with Part (b) of the problem where am not familiar with and don't know how to solve that part. I was wondering if someone can put some light in the tunnel or provide a link where I can study...
  14. William123

    Can You Ground a 3D-Printed Plastic Chassis for Electronic Projects Safely?

    Hello The Chinese were kind enough to send me a "music mixer" (XH-M164) and apparently these sell for about 8-11 dollars so I thought I might as well build something cool with it. I found an amplifier aliexpress (http://bit.ly/2nTD8VX) and the recommended transformer for that is a 32v 200VA...
  15. M

    Medical BPA free plastic also not safe?

    A relative gave me a new bottle that is free of BPA.. but researching I found out it is a Eastman Tritan which the following articles claim still contain estrogenic chemicals.. I'm still confused by the following articles...
  16. C

    What absorbs impact better, hard plastic or silicon?

    Hello, Not sure really where to ask this but I couldn't find a good answer so why not a physics forum, because well this involves physics. I just got a gopro for my fpv drone and I am wondering what type of case to get for it, either a plastic or silicone one. If I am going 30+ mph and smack...
  17. F

    3D Printing a transparent plastic object....

    Hello Forum, I am new to 3D printing and wondering if any of you have been able to print transparent plastic object with 3D printing. It seems that translucency is the best that we can get. Is that true? Are today's affordable 3D printer still only work with PLA and ABS or are there other more...
  18. Peter Hessellund

    Bingham plastic that is not a suspension

    I am looking for a Bingham plastic that is not a suspension. It can either be in the form of an additive to water or a non conductive chemical. The liquid should have a yield stress of 150 Pa to 250 Pa. What liquid could be used here? Are there companies who tailor make these kind of liquids?
  19. S

    Help Removing A Plastic Washer from Corroded Steel Shaft

    I have a plastic slinger (hdpe, I believe) that is attached to a dishwasher motor shaft that I'm trying to disassemble so that I can replace it's bearings. The sling will twist independently of the shaft, but it won't come off. I've been thinking of hitting it with a penetrating catalyst (PB...
  20. Peter Hessellund

    How do I calculate the yield pressure for a Bingham plastic in a tube?

    I have three questions. 1. How do I calculate the yield pressure for a Bingham plastic in a tube if I am given: Length of tube Diameter of tube Yield stress of liquid 2. Is it possible to engineer a liquid to have a specific yield stress ? 3. What kind of material would be suited for...
  21. E

    B Can Hydrogen-Based Plastic Provide Better Radiation Protection than Lead?

    Some days ago, i read, that there is a plastic, that should be capable of protecting from interstellar radiation. I would be interested in further information about this plastic. Someone here who has some material, i could take a look at?
  22. D

    Will my PA66 (Nylon) beam plastic deform?

    Hello, I have this model that required to be pressed vertically 1mm. I successfully displaced 1mm vertically with 30N of force. Unluckily, Von mises stress goes way beyond the yield strength. However, the strain is below the yield strain of 5%. I do not understand how ductile/flexible material...
  23. Mrinmoy Naskar

    A Plastic Scintillator: Benefits in Beta Decay Experiments

    . why plastic scintillator is more useful than other scintillator in beta decay experiment??
  24. A

    Difference between 'plastic yielding' & plastic strength?

    I am going through a literature where the terms like ( 'plastic yielding' , 'plastic yield strength', plastic strength' and 'plastic stress') are regularly used and I am confused. Are they different and if yes then how each term differs from the other? I also want to know relation of plastic...
  25. N

    Is PVC Safe? What's So Bad About Vinyl Plastic (PVC)?

    Now days PVC is widely used polymer in many industries such like real estate, pharmaceutical, plastic and rubber etc. My concern is Is PVC Safe for Environment? Can anybody tell me the cons of using PVC (Polyvinyl chloride)? Thanks for Advance!
  26. R

    Soda bubble formation rate on plastic straw and glass cup

    I observed that if you pour soda into a glass cup and leave the straw inside, bubbles seem to form on the plastic cup at a much much quicker rate. Why is this? Why do bubbles form on the straw at all? Not sure if this should be in general physics or chemistry
  27. Eureka99

    Heating Plastic: Risks & Benefits

    Hi everybody! I was wondering, what substances do form when plastic is heated? I found on the internet that if plastic is heated in the oven (not microwave) at 325°C, it shrinks and become more thick, and it can be used for art work. I tried to search about it, but I found different opinions...
  28. C

    Safely reshaping small ABS keys

    I got a used keyboard on eBay, and it works just fine except for one key. It is slightly bent on one side (no idea how they managed that without taking the key out and stepping on it or something) and is clamping down on the channel it rests in. Because of that, when it is pressed in, it stays...
  29. T

    Optimizing sound energy transfer through plastic medium

    Hi everyone, I am looking to improve the transmission of sound from a small 1/2" electro-mechanical transducer through a plastic medium (about 1/4" thick). I understand plastic is not a great medium for this but I do not have the ability to change this. The defacto setup doesn't work too...
  30. I

    Energy Loss in Plastic Scintillator

    Homework Statement Calculate the energy loss loss ##\Delta T## for protons, deuterons and ##\alpha##-particles between ##10## to ##200##MeV when they're passing through a 2mm thick plastic scintillator. Suppose ##Z/A=0.56##, ##I=65eV## and ##\rho = 1.10##g/cm^3. Homework Equations Bethe...
  31. G

    Index of when refraction/optics question

    The question A microscope is focused on a black dot. When a 1.20 cm -thick piece of plastic is placed over the dot, the microscope objective has to be raised 0.380 cm to bring the dot back into focus. What is the index of refraction of the plastic Relevant equations/ideas...
  32. yeezyseason3

    Deriving Electric Field Inside Plastic Rod Using Gauss's Law

    Homework Statement A straight circular plastic cylinder of length L and radius R (where R ≪ L) is irradiated with a beam of protons so that there is a total excess charge Q distributed uniformly throughout the cylinder. Find the electric field inside the cylinder, a distance r from the center...
  33. G

    Electricity: plastic on plastic

    We know that objects like plastic become negative (with rubbing) but what will happen if we rub plastic and plastic, one of them will become positive which one ?
  34. A

    Design Problem Lightweight Plastic String for Zipper Seams

    I need a light weight plastic material, like a string that is no more than 1/8 inch in diameter, that can be sewn into fabric alongside a zipper and spring open when the zipper opens. I would greatly appreciate any suggestions anyone is able to give. I have been trying to solve this design...
  35. 2

    B Why is the Black Piece on this Mechanism Made of Plastic?

    why is the black piece plastic instead of just extending the metal? its bolted down. is it just for the axel support? Can you think of a reason they did this? thanks for your opinions
  36. C

    B Why plastic eyeglasses have less clarity than glass?

    Anyone knows why plastic eyeglasses have less clarity than glass? What is the molecular properties of plastic eyeglasses and the behavior of light rays as it passes thru them?
  37. CARNiVORE

    Electric Field between Three Plastic Sheets

    Homework Statement Figure (a) shows three plastic sheets that are large, parallel, and uniformly charged. Figure (b) gives the component of the net electric field along an x axis through the sheets. The scale of the vertical axis is set by Es = 8.4 × 105 N/C. What is the ratio of the charge...
  38. M

    Hooke's Law and plastic materials

    Hi, About elastic and plastic materials: All materials exhibit elastic deformation up to a certain limit, beyond which they exhibit plastic deformation. Some materials, such as plasticine, have extremely tiny elastic regions, so we call them 'plastic materials'. Some, like rubber, have large...
  39. M

    Pressure in two Different Sized Plastic Bottles

    I have two different sized plastic bottles of the same material and with the same wall thickness and I raise the pressure inside the bottles at the same rate then which bottle will rupture first? The bigger bottle or the smaller one? I would think that both bottles would rupture at about the...
  40. J

    Modulus of Elasticity of a Plastic Laminated Panel

    I am trying to find a formula to show the modulus of elasticity (MOE) of a panel of three layers of different materials when I know the MOE value of the three individual materials. This is for a Plastic Laminated Panel where, the top and bottom layers are plastic laminate (i.e. Formica) .028"...
  41. mcaay

    Electrostatic forces in plastic bags

    I found a book which suggests that the reason why plastic bags are sometimes hard to open (which feels like they were glued) is electrostatic forces, but no matter how I look at this, I can't come up with any explanation. Is the book correct? I understand insulators and conductors, how charges...
  42. W

    What can glue condom material to hard plastic?

    I am manufacturing a plastic cube out of six flat, hard pieces plastic, of the same consistency as water bottle plastic. The top and bottom sides of the cube will be connected to the middle 4 panels by condom rubber. I need some kind of bendable plastic that can expand so that the cube can grow...
  43. S

    Where/how to make a plastic piston valve

    I have a project for school and need to make a hand water pump. The thing is, it needs to be a "mini" pump. I will be using 2 mini 1 way check valves and a t fitting, but the problem is i cannot find a way to make the actual piston pump. I also need a spring to draw the piston back up so i can...
  44. E

    Selecting Low cost, High heat-resistant plastics

    Hello, For a current project, I am searching for high operating temperature (200C-300C), Medium Strength (~80 Mpa UTS) and low cost plastics (or at least not extremely expensive). So far the closest I found is nylon 6/6 reinforced with 30% carbon fiber. I also found something called Vespal...
  45. T

    A plastic rod 1.9 m long is rubbed all over with wool

    Homework Statement A plastic rod 1.9 m long is rubbed all over with wool, and acquires a charge of -6e-08 coulombs. We choose the center of the rod to be the origin of our coordinate system, with the x-axis extending to the right, the y-axis extending up, and the z-axis out of the page. In...
  46. K

    Two charged beads on a plastic ring

    Homework Statement Two charged beads are on the plastic ring in Figure (a). Bead 2, which is not shown, is fixed in place on the ring, which has radius R = 63.3 cm. Bead 1 is initially on the x axis at angle θ = 0o. It is then moved to the opposite side, at angle θ = 180o, through the first and...
  47. S

    MHB Black Plastic Lid - Measurement Ratio

    Object: Black Plastic Lid $C$ = Circumference (cm) $D$ = Diameter (cm) Ratio $= \frac{C}{D}$ Ratio $= \frac{30.75}{9.46} = 3.25$
  48. B

    Can you make a type of plastic from Dibutyl Phthalate?

    Hi there, As an experiment, I am trying to make a type of plastic from Dibutyl Phthalate. I have a product here that is a slightly pliable, white plastic, that the maker lists the ingredients of as": DBP Dibutyl Phthalate and Titanium Dioxide". However when I mix these two in any ratio, they...
  49. PinkGeologist

    How "plastic" do you think heated rocks become?

    Consider a magma chamber in the Earth's crust ... models show that 1-2 km surrounding this chamber are heated above the brittle-ductile transition zone. Let's say that you know the yield strength of the crust in general (not heated) is 15 MPa ... and after that, rocks under heavy confining...
  50. PinkGeologist

    What is a hardening function? What does it represent?

    So, I was introduced tangentially to plastic deformation and hardening functions. I see we have three basic function ... and the linear and kinematic seem to be the most common defaults ... I see it is a measure of the strain of a material under stress. But how would you know which version to...
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