plastic

Published on February 2017 | Categories: Documents | Downloads: 76 | Comments: 0 | Views: 1060
of 38
Download PDF   Embed   Report

Comments

Content

HIGH DENSITY POLYETHYLENE (HDPE): HDPE refers to a plastic used to make bottles for milk, juice, water and laundry products. Unpigmented HDPE bottles are translucent and have good barrier properties and stiffness. They are well suited to packaging products with short shelf lives such as milk. Pigmented HDPE bottles generally have better stress crack and chemical resistance than bottles made with unpigmented HDPE. These properties are needed for packaging such items as household chemicals and detergents, which have a longer shelf life. Made via a low-pressure process at 1 atm and 170 degrees. Relative density: 0.941 to 0.965 grams/cubic centimetres. HDPE does not become pliable until temperatures over water’s boiling point, i.e. 100 degrees. HDPE remains stable down to -45 degrees. Good welding properties, weldable at 130 to 170 degrees.

LOW DENSITY POLYETHYLENE (LDPE): A plastic used predominantly in film applications due to its toughness, flexibility and relative transparency. LDPE has a low melting point, making it popular for use in applications where heat sealing is necessary. Typically, LDPE is used to manufacture flexible films such as those used for plastic retail bags and garment dry cleaning and grocery bags. LDPE is also used to manufacture some flexible lids and bottles, and it is widely used in wire and cable applications for its stable electrical properties and processing characteristics Made via a high pressure process at 3000 atm and 300 degrees. Low relative density: 0.91 to 0.925 grams/cubic centimetres. LDPE is a tough, semi-transparent material. LDPE becomes pliable at around 60 to 80 degrees. LDPE remains stable down to -60 degrees. Good welding properties, weldable at 110 to 140 degrees. Low permeability to aqueous vapour (steam). High permeability to gases like oxygen.

LINEAR LOW DENSITY POLYETHYLENE (LLDPE): A plastic that is used predominantly in film applications due to its toughness, flexibility and relative transparency. LLDPE is the preferred resin for mixing with LDPE, because of its superior toughness and is used in items such as grocery bags, garbage bags and landfill liners.

Made via a low-pressure process at 1 atm and 170 degrees. Low relative density: 0.91 to 0.925 grams/cubic centimetre. The production method reduces the tension in the material. This enables the production of thinner foils wit Typically used as an additive since pure LLDPE is difficult to process.

POLYPROPYLENE (PP): Polypropylene has excellent chemical resistance, is strong and has the lowest density of the plastics used in packaging. It has a high melting point, making it ideal for hot-fill liquids. In film form it may or may not be oriented (stretched). PP is found in everything from flexible and rigid packaging to fibres and large molded parts for automotive and consumer products.

POLYSTYRENE (PS):

Polystyrene is a very versatile plastic that can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It has a relatively low melting point. Typical applications include protective packaging, containers, lids, cups, bottles, trays and tumblers.

COMMON TYPES OF PLASTICS
Symbol Type of Plastic PET Properties Clear, tough solvent Common Uses Soft drink and water Recycled In Pillow and sleeping bag filling, clothing, soft drink bottles carpet

resistant, barrier to gas bottles, salad domes, Polyethylene Terephthalate and moisture, softens at around 80°C biscuit trays, salad dressing and peanut butter containers PE-HD Hard to semi-flexible, resistant to chemicals High Density Polyethylene and moisture, waxy surface, opaque, Crinkly shopping bags, freezer bags, milk bottles, ice cream

Recycling bins, compost bins, buckets, detergent

(HDPE)

containers, juice bottles, containers, posts, fencing, pipes

softens at around 75°C, shampoo, chemical and easily colored, processed and formed detergent bottles, buckets, rigid agricultural pipe, milk crates PVC Strong, tough, can be clear, can be solvent Unplasticised Polyvinyl welded, softens at around 80°C Cosmetic containers, electrical conduit, plumbing pipes and fittings, blister packs, wall cladding, roof sheeting, bottles Flexible, clear, elastic, can be solvent welded

Flooring, film and sheets, cables, speed bumps, packaging, binders, mud flaps and mats

Chloride PVC-U

Plasticised Polyvinyl Chloride PCV-P

garden hose, shoe soles, cable sheathing, blood bags and tubing, watch

straps PE-LD Soft, flexible, waxy surface, translucent, Low density Polyethylene (LDPE) softens at 70°C, scratches easily Hard but still flexible, waxy surface, softens Polypropylene at around 140°C, Plastic Food wrap, garbage bags, squeeze bottles, black irrigation tube, garbage bins Dip bottles and ice cream Pegs, bins, pipes, tubs, potato chip bags, straws, microwave pallet sheets, oil funnels, car battery cases, trays Rubbish bin liners, pallet sheets

PP

translucent, withstands dishes, kettles, garden solvents, versatile furniture, lunch boxes, blue packing tape PS Clear, glassy, rigid, brittle, opaque, semiPolystyrene

CD cases, plastic cutlery, Coat hangers, imitation 'crystal coasters, white ware components, stationery trays and accessories

tough, softens at 95°C. glassware', low cost Affected by fats and solvents brittle toys, video cases

PS-E

Expanded Polystyrene Foamed, light weight,

Foamed polystyrene hot drink cups, hamburger

energy absorbing, heat takeaway clamshells, insulating foamed meat trays, protective packaging for fragile items OTHER Includes all other resins Car parts, appliance and multi materials Letters below indicate ISO Car parts, concrete

parts, electronics, water aggregate, plastic

(e.g. laminates). code for plastic type e.g. SAN, ABS, PC, Nylon Properties depend on plastic or combination of plastics

cooler bottles, packaging timber

Types of Plastics
Recycling Resources Recycling Facts Recycling Pictures

In an attempt to bring order to plastics classification for recycling purposes, the Society of the Plastics Industry (SPI) devised some voluntary codes in 1988. They are commonly called SPI codes, and the numbers within the recycling arrows refer to different types of plastic resins. There is no federal regulation governing the types of symbols you see stamped to plastic, so you can not be certain of consistency from state to state. However, with SPI codes, it is generally safe to assume some consistency.

PET (polyethylene terephthalate): plastic soft drink bottles, water bottles, beer bottles, mouthwash bottles and many more


HDPE (high density polyethylene): milk bottles, detergent bottles, oil bottles, toys, plastic bags


PVC (polyvinyl chloride): food wrap, vegetable oil bottles, blister packaging


LDPE (low density polyethylene): bread bags, frozen food bags, squeezable bottles, fiber, tote bags, bottles, clothing, furniture, carpet, shrink-wrap, garment bags


PP (polypropylene): margarine and yogurt containers, caps for containers, wrapping to replace cellophane


PS (polystyrene): egg cartons, fast food trays, disposable plastic silverware


Other: This code indicates that the item is made with a resin other than the six listed above, or a combination of different resins.


© 2002. Patricia A. Michaels.

Material Properties Recommended application Noryl Extremely good mechanical, thermal and electrical properties. Good ageing stability and weathering resistance. High stability against chemicals. Dimensionally stable, heat-resistant, self-extinguishing parts, mainly when exchanged with metal. Component parts and cases for entertainment industry and data processing units. Polyamide Thermoplastic with high temperature stability, extremely solid and tenacious. Good sliding properties and high capacity of resistance to

wear. Contact with humidity may result in a change of properties. Ideally suited for technical application, especially for machine elements with complicated geometry. Polycarbonate Thermoplastic with high temperature stability with excellent resistance to all kinds of temperature. On the whole, good resistance against chemicals and UV-light. Recommended for cases housing instruments and general indoor and outdoor application. Not recommended for use with strong alkalis or for direct exposure to sunlight. PC-ABS Blend Good stability in case of high temperature combined with enormous impact strength as well as toughness at subzero temperature. On the whole, good resistance against chemicals. UV-light may have a negative effect. Ideally suited for indoor use with moderate corrosive conditions. Limited outdoor suitablility. Special materials comply with ball-thrust hardness test according to VDE 700 at 125°C. ABS Good resistance against medium temperature combined with good impact strength (only certain types) and antistatic adjustment. On the whole, good resistance against chemicals. UV-light may have a negative effect. Cases and operating elements of all kinds. Indoor use, also suitable for low temperature. Limited outdoor application. Suitable for galvanic coating. Polystyrene Normally brittle and resistant to fairly low temperature. SB-types are impact resistant and less sensitive to tearing under pressure. Glossy surface. Metal-cutting is possible. For cases and operating elements with working temperature of less

than 65°C. Suitable for indoor use. Exposure to UV-light should be avoided. PMMA (plexiglass® ) Good mechanical properties, slightly brittle. Superior from optical point of view. Permeable to light up to 92% for certain types. Cases and front panels for infrared transmitters and receivers as well as transparent parts. COMBUSTIBILITY TEST FOR PLASTICS ACCORDING TO U L SUBJECT 94

Types
This section may require cleanup to meet Wikipedia's quality standards. Please improve this section if you can. The talk page may contain suggestions. (June 2009) [edit]Cellulose-based

plastics

Parkes developed a synthetic replacement for ivory which he marketed under the trade name Parkesine, and which won a bronze medal at the 1862 World's fair in London. Parkesine was made from cellulose (the major component of plant cell walls) treated with nitric acid and a solvent. The output of

the process (commonly known as cellulose nitrate or pyroxilin) could be dissolved in alcohol and hardened into a transparent and elastic material that could be molded when heated.[14] By incorporating pigments into the product, it could be made to resemble ivory. Bois Durci is a plastic molding material based on cellulose. It was patented in Paris by Lepage in 1855. It is made from finely ground wood flour mixed with a binder, either egg or blood albumen, or gelatine. The wood is probably either ebony or rose wood, which gives a black or brown resin. The mixture is dried and ground into a fine powder. The powder is placed in a steel mold and compressed in a powerful hydraulic press while being heated by steam. The final product has a highly polished finish imparted by the surface of the steel mold.
[edit]Bakelite

Main article: Bakelite

The first so called plastic based on a synthetic polymer was made from phenol and formaldehyde, with the first viable and cheap synthesis methods invented in 1907, by Leo Hendrik Baekeland, a Belgian-born American living in New York state. Baekeland was searching for an insulating shellac to coat wires in electric motors and generators. He found that mixtures of phenol (C6H5OH) and formaldehyde (HCOH) formed a sticky mass when mixed together and heated, and the mass became extremely hard if allowed to cool. He continued his investigations and found that the material could be mixed with wood flour, asbestos, or slate dust to create "composite" materials with different properties. Most of these compositions were strong and fire resistant. The only problem was that the material tended to foam during synthesis, and the resulting product was of unacceptable quality.

Baekeland built pressure vessels to force out the bubbles and provide a smooth, uniform product. He publicly announced his discovery in 1912, naming it bakelite. It was originally used for electrical and mechanical parts, finally coming into widespread use in consumer goods in the 1920s. When the Bakelite patent expired in 1930, the Catalin Corporation acquired the patent and began manufacturing Catalin plastic using a different process that allowed a wider range of coloring. Bakelite was the first true plastic. It was a purely synthetic material, not based on any material or even molecule found in nature. It was also the first thermosetting plastic. Conventional thermoplastics can be molded and then melted again, but thermoset plastics form bonds between polymers strands when cured, creating a tangled matrix that cannot be undone without destroying the plastic. Thermoset plastics are tough and temperature resistant.

Bakelite was cheap, strong, and durable. It was molded into thousands of forms, such as cases for radios, telephones and clocks, andbilliard balls. Phenol-based ("Phenolic") plastics have been largely replaced by cheaper and less brittle plastics, but they are still used in applications requiring their insulating and heat-resistant properties. For example, some electronic circuit boards are made of sheets of paper or cloth impregnated with phenolic resin.
[edit]Polystyrene

and Polyvinyl Chloride

Main articles: Polystyrene and PVC

Plastic piping and firestops being installed in Ontario. Certain plastic pipes can be used in some non-combustible buildings, provided they are firestopped properly and that the flame spread ratings comply with the localbuilding code.

After the First World War, improvements in chemical technology led to an explosion in new forms of plastics. Among the earliest examples in the wave of new plastics were polystyrene (PS) and polyvinyl chloride (PVC). Polystyrene is a rigid, brittle, inexpensive plastic that has been used to make plastic

model kits and similar knick-knacks. It would also be the basis for one of the most popular "foamed" plastics, under the name styrene foam or Styrofoam. Foam plastics can be synthesized in an "open cell" form, in which the foam bubbles are interconnected, as in an absorbent sponge, and "closed cell", in which all the bubbles are distinct, like tiny balloons, as in gas-filled foam insulation and flotation devices. In the late 1950s, high impact styrene was introduced, which was not brittle. It finds much current use as the substance of toy figurines and novelties.

Polyvinyl Chloride (PVC, commonly called "vinyl")[15] has side chains incorporating chlorine atoms, which form strong bonds. PVC in its normal form is stiff, strong, heat and weather resistant, and is now used for making plumbing, gutters, house siding,

enclosures for computers and other electronics gear. PVC can also be softened with chemical processing, and in this form it is now used for shrink-wrap, food packaging, and rain gear.

All PVC polymers are degraded by heat and light. When this happens, hydrogen chloride is released into the atmosphere and oxidation of the compound occurs. [16] Because hydrogen chloride readily combines with water vapor in the air to form hydrochloric acid,[17] polyvinyl chloride is not recommended for long-term archival storage of silver, photographic film or paper (mylar is preferable).[18]
[edit]Nylon

Main article: Nylon The real star of the plastics industry in the 1930s was polyamide (PA), far better known by its trade name nylon. Nylon was the first

purely synthetic fiber, introduced by DuPont Corporation at the 1939 World's Fair in New York City. In 1927, DuPont had begun a secret development project designated Fiber66, under the direction of Harvard chemist Wallace Carothers and chemistry department director Elmer Keiser Bolton. Carothers had been hired to perform pure research, and he worked to understand the new materials' molecular structure and physical properties. He took some of the first steps in the molecular design of the materials. His work led to the discovery of synthetic nylon fiber, which was very strong but also very flexible. The first application was for bristles fortoothbrushes. However, Du Pont's real target was silk, particularly silk stockings. Carothers and his team synthesized a number of different polyamides including polyamide 6.6 and 4.6, as well as polyesters.[19]

General condensation polymerization reaction for nylon

It took DuPont twelve years and US$27 million to refine nylon, and to synthesize and develop the industrial processes for bulk manufacture. With such a major investment, it was no surprise that Du Pont spared little expense to promote nylon after its introduction, creating a public sensation, or "nylon mania". Nylon mania came to an abrupt stop at the end of 1941 when the USA entered World War II. The production capacity that had been built up to produce nylon stockings, or just nylons, for American women was taken over to manufacture vast numbers of parachutes for fliers and paratroopers. After the war ended, DuPont went back to selling nylon to the public, engaging in another promotional campaign in 1946 that resulted

in an even bigger craze, triggering the so called nylon riots. Subsequently polyamides 6, 10, 11, and 12 have been developed based on monomers which are ring compounds; e.g. caprolactam. Nylon 66 is a material manufactured by condensation polymerization. Nylons still remain important plastics, and not just for use in fabrics. In its bulk form it is very wear resistant, particularly if oilimpregnated, and so is used to build gears, plain bearings, and because of good heat-resistance, increasingly for under-thehood applications in cars, and other mechanical parts.
[edit]Rubber

Natural rubber is an elastomer (an elastic hydrocarbon polymer) that was originally derived from latex, a milky colloidal suspension found in the sap of some plants. It is useful directly in this form (indeed, the first appearance of rubber in Europe is cloth waterproofed with unvulcanized latex from

Brazil) but, later, in 1839, Charles Goodyear invented vulcanized rubber; this a form of natural rubber heated with, mostly, sulfur forming cross-links between polymer chains (vulcanization), improving elasticity and durability.
[edit]Synthetic

rubber

Main article: Synthetic rubber The first fully synthetic rubber was synthesized by Sergei Lebedev in 1910. In World War II, supply blockades of natural rubber from South East Asia caused a boom in development of synthetic rubber, notably styrene-butadiene rubber. In 1941, annual production of synthetic rubber in the U.S. was only 231 tonnes which increased to 840,000 tonnes in 1945. In the space race and nuclear arms race, Caltechresearchers experimented with using synthetic rubbers for solid fuel for rockets. Ultimately, all large military rockets and missiles would use synthetic rubber

based solid fuels, and they would also play a significant part in the civilian space effort. [edit]Toxicity Due to their insolubility in water and relative chemical inertness, pure plastics generally have low toxicity in their finished state, and will pass through the digestive system with no ill effect (other than mechanical damage or obstruction). However, plastics often contain a variety of toxic additives. For example, plasticizers like adipates and phtha lates are often added to brittle plastics like polyvinyl chloride (PVC) to make them pliable enough for use in food packaging, toys and teethers, tubing, shower curtains and other items. Traces of these chemicals can leach out of the plastic when it comes into contact with food. Out of these concerns, the European Union has banned the use of DEHP (di-2-ethylhexyl phthalate), the most widely used plasticizer in PVC. Some compounds leaching from polystyrene food containers have been found to interfere

with hormone functions and are suspected human carcinogens.[20] Moreover, while the finished plastic may be non-toxic, the monomers used in its manufacture may be toxic; and small amounts of those chemicals may remain trapped in the product. The World Health Organization's International Agency for Research on Cancer (IARC) has recognized the chemical used to make PVC, vinyl chloride, as a known human carcinogen. [20] Some polymers may also decompose into the monomers or other toxic substances when heated. The primary building block of polycarbonates, bisphenol A (BPA), is an estrogen-like endocrine disruptor that may leach into food.[20]Research in Environmental Health Perspectives finds that BPA leached from the lining of tin cans, dental sealants and polycarbonate bottles can increase body weight of lab animals' offspring.[21] A more recent animal

study suggests that even low-level exposure to BPA results in insulin resistance, which can lead to inflammation and heart disease.
[22]

As of January 2010, the LA Times newspaper reports that the United States FDA is spending $30 million to investigate suspicious indications of BPA being linked to cancer.[23] Bis(2-ethylhexyl) adipate, present in plastic wrap based on PVC, is also of concern, as are the volatile organic compounds present in new car smell. The European Union has a permanent ban on the use of phthalates in toys. In 2009, the United States government banned certain types of phthalates commonly used in plastic.[24] [edit]Environmental issues Further information: Marine debris Plastics are durable and degrade very slowly; the molecular bonds that make

plastic so durable make it equally resistant to natural processes of degradation. Since the 1950s, one billion tons of plastic have been discarded and may persist for hundreds or even thousands of years.[25] In some cases, burning plastic can release toxic fumes. Burning the plastic polyvinyl chloride (PVC) may create dioxin.[26] Also, the manufacturing of plastics often creates large quantities of chemical pollutants. Prior to the ban on the use of CFCs in extrusion of polystyrene (and general use, except in life-critical fire suppression systems; seeMontreal Protocol), the production of polystyrene contributed to the depletion of the ozone layer; however, nonCFCs are currently used in the extrusion process. By 1995, plastic recycling programs were common in the United States and elsewhere. Thermoplastics can be remelted and reused, and thermoset plastics can be ground up and used as filler, though the purity of the

material tends to degrade with each reuse cycle. There are methods by which plastics can be broken back down to a feedstock state. Plastic can be converted as a fuel. Plastic is made from crude, so it can be broken down to liquid hydrocarbon. One kilogram of waste plastic produces a liter of hydrocarbon. Plastic wastes are used in cement plants as a fuel.[27][28][29] To assist recycling of disposable items, the Plastic Bottle Institute of the Society of the Plastics Industry devised a now-familiar scheme to mark plastic bottles by plastic type. A plastic container using this scheme is marked with a triangle of three "chasing arrows", which encloses a number giving the plastic type:

Plastics type marks: the resin identification code

PET (PETE), polyethylene terephthalate
1.

HDPE, high-density polyethylene 3. PVC, polyvinyl chloride 4. LDPE, low-density polyethylene, 5. PP, polypropylene 6. PS, polystyrene 7. Other types of plastics (see list, below)
2.

Unfortunately, recycling of plastics has proven to be a difficult process. The biggest problem is that it is difficult to automate the sorting of plastic wastes, making it labor intensive. Typically, workers sort the plastic by looking at the resin identification code, although common containers like soda bottles can be sorted from memory. Typically, the caps for PETE bottles are made from a different kind of plastic which is not recyclable, which presents additional problems to the automated sorting process. Other recyclable materials such as metals are easier to process mechanically. However, new processes of mechanical

sorting are being developed to increase capacity and efficiency of plastic recycling. While containers are usually made from a single type and color of plastic, making them relatively easy to be sorted, a consumer product like a cellular phone may have many small parts consisting of over a dozen different types and colors of plastics. In such cases, the resources it would take to separate the plastics far exceed their value and the item is discarded. However, developments are taking place in the field ofactive disassembly, which may result in more consumer product components being re-used or recycled. Recycling certain types of plastics can be unprofitable, as well. For example, polystyrene is rarely recycled because it is usually not cost effective. These unrecycled wastes are typically disposed of in landfills, incinerated or used to produce electricity at waste-toenergy plants.

[edit]Biodegradable

(compostable) plastics

Main article: Biodegradable plastic Research has been done on biodegradable plastics that break down with exposure to sunlight (e.g., ultra-violet radiation), water or dampness, bacteria, enzymes, wind abrasion and some instances rodent pest or insect attack are also included as forms of biodegradation orenvironmental degradation. It is clear some of these modes of degradation will only work if the plastic is exposed at the surface, while other modes will only be effective if certain conditions exist in landfill or composting systems. Starch powder has been mixed with plastic as a filler to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Some researchers have actually genetically engineered bacteria that synthesize a completely biodegradable plastic, but this material, such as Biopol, is expensive at present.[30] TheGerman chemical

company BASF makes Ecoflex, a fully biodegradable polyester for food packaging applications.
[edit]Bioplastics

Main article: Bioplastic Some plastics can be obtained from biomass, including: from pea starch film with trigger biodegradation properties for agricultural applications (TRIGGER).[31] [32]  from biopetroleum.


[edit]Oxo-biodegradable

Main article: Oxo Biodegradable Oxo-biodegradable (OBD) plastic is polyolefin plastic to which has been added very small (catalytic) amounts of metal salts. As long as the plastic has access to oxygen (as in a littered state), these additives catalyze the natural degradation process to speed it up so that the OBD plastic will degrade when subject to environmental

conditions. Once degraded to a small enough particle they can interact with biological processes to produce to water, carbon dioxide and biomass. The process is shortened from hundreds of years to months for degradation and thereafter biodegradation depends on the microorganisms in the environment. Typically this process is not fast enough to meet ASTM D6400 standards for definition as compostable plastics. [edit]Price, environment, and the future The biggest threat to the conventional plastics industry is most likely to be environmental concerns, including the release of toxic pollutants,greenhouse gas, litter, biodegradable and nonbiodegradable landfill impact as a result of the production and disposal of petroleum and petroleum-based plastics. Of particular concern has been the recent accumulation of enormous quantities of plastic trash in ocean gyres.

For decades one of the great appeals of plastics has been their low price. Yet in recent years the cost of plastics has been rising dramatically. A major cause is the sharply rising cost of petroleum, the raw material that is chemically altered to form commercial plastics. With some observers suggesting that future oil reserves are uncertain, the price of petroleum may increase further. Therefore, alternatives are being sought. Oil shale and tar oil are alternatives for plastic production but are expensive. Scientists are seeking cheaper and better alternatives to petroleum-based plastics, and many candidates are in laboratories all over the world. One promising alternative may be fructose.[33] [edit]Common plastics and uses

A chair made with a polypropylene seat

Polyester (PES) - Fibers, textiles.  Polyethylene terephthalate (PET) Carbonated drinks bottles, peanut butter jars, plastic film, microwavable packaging.  Polyethylene (PE) - Wide range of inexpensive uses including supermarket bags, plastic bottles.  High-density polyethylene - Detergent bottles and milk jugs.  Polyvinyl chloride (PVC) - Plumbing pipes and guttering, shower curtains, window frames, flooring.


Polyvinylidene chloride (PVDC) (Saran) Food packaging.  Low-density polyethylene (LDPE) - Outdoor furniture, siding, floor tiles, shower curtains, clamshell packaging.  Polypropylene (PP) - Bottle caps, drinking straws, yogurt containers, appliances, car fenders (bumpers), plastic pressure pipe systems.  Polystyrene (PS) - Packaging foam/"peanuts", food containers, plastic tableware, disposable cups, plates, cutlery, CD and cassette boxes.  High impact polystyrene (HIPS) -: Refrigerator liners, food packaging, vending cups.  Polyamides (PA) (Nylons) - Fibers, toothbrush bristles, fishing line, under-thehood car engine moldings.  Acrylonitrile butadiene styrene (ABS) Electronic equipment cases (e.g., computer monitors, printers, keyboards), drainage pipe.


Polycarbonate (PC) - Compact discs, eyeglasses, riot shields, security windows, traffic lights, lenses.  Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS) - A blend of PC and ABS that creates a stronger plastic. Used in car interior and exterior parts, and mobile phone bodies.  Polyurethanes (PU) - Cushioning foams, thermal insulation foams, surface coatings, printing rollers (Currently 6th or 7th most commonly used plastic material, for instance the most commonly used plastic found in cars).


[edit]Special


purpose plastics

Melamine formaldehyde (MF) - One of the aminoplasts, and used as a multicolorable alternative to phenolics, for instance in moldings (e.g., breakresistance alternatives to ceramic cups, plates and bowls for children) and the

decorated top surface layer of the paper laminates (e.g., Formica).  Plastarch material - Biodegradable and heat resistant, thermoplastic composed of modified corn starch.  Phenolics (PF) or (phenol formaldehydes) - High modulus, relatively heat resistant, and excellent fire resistant polymer. Used for insulating parts in electrical fixtures, paper laminated products (e.g., Formica), thermally insulation foams. It is a thermosetting plastic, with the familiar trade name Bakelite, that can be molded by heat and pressure when mixed with a filler-like wood flour or can be cast in its unfilled liquid form or cast as foam (e.g., Oasis). Problems include the probability of moldings naturally being dark colors (red, green, brown), and as thermoset it is difficult to recycle.  Polyetheretherketone (PEEK) - Strong, chemical- and heat-resistant

thermoplastic, biocompatibility allows for use in medical implantapplications, aerospace moldings. One of the most expensive commercial polymers.  Polyetherimide (PEI) (Ultem) - A high temperature, chemically stable polymer that does not crystallize.  Polylactic acid (PLA) - A biodegradable, thermoplastic found converted into a variety of aliphatic polyesters derived from lactic acid which in turn can be made by fermentation of various agricultural products such as corn starch, once made from dairy products.  Polymethyl methacrylate (PMMA) Contact lenses, glazing (best known in this form by its various trade names around the world; e.g., Perspex, Oroglas, Plexiglas), aglets, fluorescent light diffusers, rear light covers for vehicles. It forms the basis of artistic and commercialacrylic paints when suspended in water with the use of other agents.

Polytetrafluoroethylene (PTFE) - Heatresistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumber's tape and water slides. It is more commonly known as Teflon.  Urea-formaldehyde (UF) - One of the aminoplasts and used as a multi-colorable alternative to phenolics. Used as a wood adhesive (for plywood, chipboard, hardboard) and electrical switch housings.


[edit]

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close