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Introduction to PlasticsChapter 1

Professor Joe Greene

CSU, CHICO

August 25, 1999MFGT 041

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Chapter 1: Introduction to Plastics

• Objectives– Definition of Plastics– Uses of Plastics and Composites– History of Plastics– Raw Material Supply and Pricing– Strategic Materials

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Automotive Applications ofPlastics and Composites

n Composite Intensive Vehicles

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Automotive Plastics and Composites Use

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Automotive Plastics and Composites Use

• Exterior– doors (Saturn, Camaro, Viper, Corvette)– hoods (Viper, Corvette, Ford trucks, Heavy duty trucks)– fenders (Saturn, Corvette, Viper)– bumper covers (all cars have soft fascia)

• Interior– instrument panels, door trim, seats, consoles

• Engine– valve covers, intake manifolds, fluid containers, etc.

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Recreational Plastics and Composites Use

• Snow Equipment– skis, snow boards, snow mobiles, etc.

• Water Sports Equipment– water skis, water crafts, snorkel equipment, fishing gear– diving equipment and clothes– drinking containers

• Land Sports Equipment– shoes, roller blades, skate boards, tennis, golf, etc.

• Air Sports Equipment– plane kits, sky diving clothing and equipment

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Medical Plastics and Composites Use

• Containers– bottles, blister packages

• Medical drug delivery systems– IV bags, time release coatings for drugs– tubing and cathoders for surgery

• Medical Equipment– Clothing, needle containers, etc.

• The use of plastic materials in the medical field is constantly increasing and is estimate to reach 4 billion dollars by 2000 (only in the US).

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Commercial Plastics Usage

• Packaging– Wrapping, bags, bottles, blister packages, shrink wrap.

• Textiles– Clothing, carpets, fabrics, diapers, netting for sports

• Furniture, Appliances, Housewares– Telephones and other communication equipment, computer

housings and cabinets, luggage, seating, components for washers, dryers, etc.

– Musical instruments, CDs, VCRs, TVs, cases

• Construction– Moldings, counter tops, sinks, flooring, cups, paints, etc.

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Definition of Plastics• Plastics come from the Greek plastikos, which means to form or mold.

– Plastics are solids that flow (as liquid, molden, or soften state) when heat is applied to material.

• Polymers are organic materials that come from repeating molecules or macromolecules

– Polymer materials are made up of “many” (poly) repeating “units”(mers).

– Polymers are mostly based in carbon, oxygen, and hydrogen. Some have Si,

F, Cl, S

– Polymers are considered a bowl of spaghetti or a bag of worms in constant

motion.

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Definition of Plastics

All Materials

Gases SimpleLiquids

Solids

Metals Polymers(polymeric molecules)

Ceramics

ThermosetsHeat Setting

ThermoplasticsHeat Forming

Elastomers

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History• Natural Plastics• Early Modified Natural Materials• Early Synthetic Plastics• Commercial Synthetic Plastics• Petroleum Basis• Chronology of Polymer Science and Technology• World Production and Per Capita Consumption• Growth Comparison, Plastics and Gross National Product

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Natural Plastics• Horn

– Applications- Spoons, combs, and lantern windows

– Properties- strong, did not rust, no bad odor or residue, good impact, some-what ductile

– History• (2000 B.C.) Pharaohs of Egypt. Craftsmen softened tortoise shells in oil,

pressed into shape, trimmed, sanded, and polished.

• (1700s England) Boil horns in water or alkaline solutions and then pressed.

• (1700s America) Horners made combs and buttons.

– Issues• Lack of flowability of horn and nonuniformity in size and flexibility.

• Lack of decorative buttons and moldable material

• Strong odor and waste products from horns, hooves, and other horn materials

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Natural Plastics• Shellac

– History• Insect material from small lac bug (Asia and India)

• Female lives off of sap from tree and is covered in sap.

• The harden excretion is Shellac (shell of a lac)

– Applications• Protective coating for furniture

• Moldable plastic (US in 1852) for cases, buttons, knobs, electrical insulation, phonograph ecords (till 1930s)

– Issues• Volume and quality of material

• Arduous cleaning process

• Moisture absorption

• Inconsistent color

• Aging

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Natural Plastics• Gutta percha

– History• Palaquium gutta trees from the Malay peninsula• (1843) Gutta percha was used to make knife handles

– Properties• Softened in hot water and then pressed into desired shape• Solid at room temperature and is ductile and strong• At higher temperature it can be drawn out into strips with no recoil like rubber• Highly inert and resists vulcaization

– Applications• Excellent insulator for Transatlantic Cables (Used until the 1930s)

– Issues• Inconsistent properties and supply volumes• Contamination

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Early Modified Natural Materials• Natural Rubber (gum rubber_ natural latex)

– Little industrial significance compared to gutta percha

– Melted in hot temperatures and cracked in cold temperatures

– Vulcanization of rubber with sulfer (1839) by Goodyear

– Small amounts of sulfer = rubber; Large amounts = ebonite (hard)

– Civil War required large amounts of rubber

– Today- Rubber is a multi Billion $ business

• Celluloid (substitute for horn, ivory, tortoise shell)– Conversion of cotton into nitrocellulose (sulfuric acid and nitric

acid): highly nitrated is explosive, moderately nitrated is useful

– Pyroxylin is soluble in several solvents, used as a finish.

– Solid Pyroxylin called celluloid (powdered Pyroxylinwith pulverized gum camphor) heated and molded for Billiard balls.

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Early Synthetic Plastics

• Phenolics (named Bakelite by Leo Bakeland)– Phenol and formaldehyde reaction after heat– Resin could be shaped and hardened with heat– Replacement for celluloid for billiard balls (1909)

• Phenolics used for telephone equipment (1912)– Phenolics used for automotive electrical (1916)– Used for handles for cooking pans and electrical switches– Excellent thermal and electrical insulator– Coatings for paper and wood (Formica) and adhesive for particle board. – In 1991 US Plastics industry used 165 millions pounds

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Commercial Synthetic Plastics

• Several Polymers found by mixing simple gases under extreme conditions (high heat and pressure)– Ethylene gas to form polyethylene using addition polymerization.

– Modifications to ethylene gas to form PVC, polystyrene, polypropylene, and polymethyl methacrylate.

– Nylon discovered by Dr. Carothers (Harvard) and a new method called condensation polymerization in 1930s with DuPont.

– Polyesters, PBT and PET, produced via condensation.

• Post WWII boom in plastics– PTFE, synthetic rubber, polyesters, ABS, polycarbonates,

polyurethanes, etc.

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Petroleum Basis• Plastics are made from small molecules (monomers) that

are usually derived from crude oil.– Exception is ethylene which about 50% comes from natural

gas and 50% from crude oil– Exception is some plastics can be derived from coal, corn,

oats, tree sap, fish oil, and other natural oils.

• U.S. Petroleum Consumption in 1998– 62% Transportation– 25% Industrial (excluding plastics)– 11% Residential and Commercial– 2% Plastics

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US Plastics Sales Growth

0

10

20

30

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1980 1985 1990 1995 2000

YearM

etr

ic T

on

s (

K)

Series1

Growth Comparison, US Plastics• From 1984 to 1994

growth of 5% annually

• In 1991, Plastics account for 11% of all Shipments in US

• In 1991, Plastics. account for 3% of US workforce.

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Current Status of the Plastics Industry• Major Plastic Materials

• Recycling of Plastics

• Disposal by Incineration or Degradation

• Organizations in the Plastics Industry

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Major Plastic Materials (1995)• LDPE ($0.38/lb) 6.4 M metric tons (1000 kg)• HDPE ($0.29/lb) 5.3 M metric tons • PVC ($0.26/lb) 5.1 M metric tons • PP ($0.28/lb) 4.4 M metric tons • PS ($0.38/lb) 2.7 M metric tons • PU ($0.94/lb) 1.7 M metric tons • PET ($0.53/lb) 1.6 M metric tons • Phenolic ($0.75/lb) 1.5 M metric tons

Total 28.6 M metric tons (82% of market)

• Nylon ($1.40/lb) 0.4 M metric tons • PTFE ($6.50/lb) <0.1 M metric tons

• PEEK ($36.00/lb) <0.05 M metric tons

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Price Volume Relationship of Materials

• Figure 1.4

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Recycling of Plastics• State and Federal Legislation

• PET bottle recycling

• Codes for plastics– 1 PET– 2 HDPE– 3 Vinyl/PVC– 4 LDPE– 5 PP– 6 PS– 7 Other

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Disposal by Incineration or Degradation

• Landfill

• Incineration

• Pyrolysis

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Organizations in the Plastics Industry• SPE: Society of Plastics Engineers, http://www.4spe.org/

• SPI: Society of the Plastics Industry, http://www.socplas.org/

• SAMPE: Society for the Advancement of Material and Process Engineering, http://www.sampe.org/

• CFA: Composites Fabricators Association, http://www.cfa-hq.org/

• CFECA: California Film Extruders & Converters Association, http://www.cfeca.org/