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Most plastics are thermoplastics. Most thermoplastics are commodity. JUST print out slides 1 – 30!!!. Engineering Thermoplastics. The most common!! Acrylonitrile Butadiene Styrene (ABS) Polycarbonate (PC) Polyamides (PA or Nylon). Polymer Materials. Engineering Resins ABS Nylon
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Most plastics are thermoplastics. Most thermoplastics are commodity.
JUST print out slides 1 – 30!!! Engineering Thermoplastics The most common!! Acrylonitrile Butadiene Styrene (ABS) Polycarbonate (PC) Polyamides (PA or Nylon)
Polymer Materials • Engineering Resins • ABS • Nylon • Polycarbonate • Acetal • Acrylic • Cellulosics • Ionomer
Polymer Materials • Engineering Resins (cont) • PBT • PET • PPO
Acrylonitrile Butadiene Styrene ABS EXCELLENT CHEMICAL RESISITANCE!!
Acrylonitrile Butadiene Styrene (ABS) • This is an ethenic engineering plastic • i.e. basic monomer structure as ethylene – just modifying polystyrene by: • Adding plasticizer and copolymers of styrene butadiene and styrene acrylonitrile to produce a polystyrene terpolymer of acrylonitrile, butadiene and styrene (ABS).
ABS butadiene
ABS • Major Uses • Appliance Housings • Canoes • Typewriter Keys • Pipes & Pipe Fittings • Telephone Housings
ABS • Why would you want to use it? • Low to Medium Cost • Good Impact Strength • Good Chemical Resistance • High Gloss Surface Finish • Good Flexural Properties
ABS • Processes • Injection Molding • Extrusion • Blow Molding • Thermoforming
ABS • Long Term Service Temperature • Max = 135° • Min = Already below Tg
Nylon PA - Polyamide http://www.sdplastics.com/nylon.html http://www.ides.com/generics/Nylon/Nylon_typical_properties.htm HIGHEST STRENGTH THERMALPLASTIC!!
Basic Info • Polyamides (nylon) are polymers formed as a condensation product of an acid and amine. They all contain the characteristic amide group: CO-NH. ** suffixes refer to the number of carbon atoms in each reacting substances involved in condensation process. They are used as an identification factor. Nylons with a period between the numbers are homopolymers; nylons with a slash (/) between numbers are a cop0lymner (ex. Nylon 6/12 is a copolymer of nylons 6 and 12) • Types • Most Common • Nylon 6 • Nylon 6/6 • Nylon 6/10 • Nylon 6/12 • Nylon 11 • Nylon 12
Nylon Nylon 6/6 • Crystalline – Yes, very flexible • Hygroscopic – Yes (O and N) • Glass Transition = (135 F) • Flammability – Varies depending on additives, but will usually self extinguish because of N
Nylon • Major Uses • Structural parts!! (i.e. replacement for cast aluminum 380 series) • Electrical Connectors • Gears • Bearings • Cables, Ties, Rope • Fishing Line • Automotive Valve Covers/Oil Pans • Sports/Exercise Equipment • Tools
Nylon • Why would you want to use it? • High Strength – among the highest of all engineering plastics • Good candidate for structural parts • Good Heat Resistance (continuous use up to 260 F, bonded to rubber in molds up to 350 F) • Good Chemical Resistance • Excellent Wear Resistance • Good Fatigue Resistance
Nylon • Processes • Injection Molding • Extrusion • Blow Molding • Rotational Molding • Thermoforming
More on Nylon • One of the first “engineering” plastics (30s). • Crystalline thermoplastic • Can have tensile properties comparable to soft aluminum. • Types 6 and 6/6 are the cheapest and most common (also worst for moisture absorption)!! These two grades = 90% of production in US. Also, highest strength grades. • Biggest disadvantage – tendency to absorb moisture after prolonged period (up to 10% by weight) which causes war page. • Nylon 12 – best moisture resistant grade
Su = 35 ksi!! **Discuss bearing plate project for RuR, show samples
Polycarbonates (PC) IMPACT STRENGTH!!
Polycarbonate • Crystalline – No, too rigid • Hygroscopic – Yes (O) • Glass Transition – High (300 F) • Flammability – No (High number of double carbon bonds will extinguish –soot)
Polycarbonates (PC) • Polycarbonates are amorphous linear polyesters with excellent moldability. • Good impact strength, temperature resistance. • Transparent (aka Plexiglas) • Tensile strength similar to ABS and nylon except impact strength can be 10X greater! But……Costs more and susceptible to environmental stress cracking.
Polycarbonates (PC) • Uses include: • Helmets (football and hard hats), face shield,power tool housings, cell phones, automotive dashboards, window cranks, small gears, etc.
Polyoxymethylene(Acetal or POM) • Crystalline – Yes, very flexible • Hygroscopic – Yes (O) • Glass Transition – Low (-100 F) • Flammability – Yes (only C and O bonds)
Acetal • Major Uses • Gears • Bearings • Faucet Components • Fuel Pump Components • Refrigerator Clips • Zippers
Acetal • Why would you want to use it? • Low to Medium Cost • Good Chemical Resistance • High Strength • Excellent Fatigue • Good Creep Resistance • Lubricity • Dimensional Stability at High Temperature
Acetal • Processes • Injection Molding • Extrusion • Blow Molding • Rotomolding
Acetal • Long Term Service Temperature • Max = 200° • Min = ~ -100
Acetal • Material Suppliers • DuPont • Hoechst Celanese • BASF • LNP
Acrylic PMMA
Polymethylmethacrylate (Acrylic) • Crystalline – No, too rigid (dual methyl groups) • Hygroscopic – Yes (O) • Glass Transition – High (220 F) • Flammability – Yes (only C-H and C=O bonds)
Acrylic • Major Uses • Sheet • Windows • Displays • Signs • Surgical Instruments
Acrylic • Why would you want to use it? • Low Cost • Good Chemical Resistance • Hardness • Good Creep Resistance • Transparency • Best Polymer for Weatherability
Acrylic • Processes • Casting • Injection Molding • Extrusion • Thermoforming
Acrylic • Long Term Service Temperature • Max = 80° • Min = Already below Tg
Acrylic • Material Suppliers • AtoHaas • Continental • DuPont • ICI
Cellulosic • Major Uses • Tool Handles • Safety Glasses • Tooth Brush Handles • Automotive and Furniture Trim • Toys • Tubing • Writing Instruments
Cellulosic • Why would you want to use it? • Low Cost • Medium Chemical Resistance • Hardness • Transparency • Rigid
Cellulosic • Processes • Casting • Injection Molding • Extrusion
Cellulosic • Long Term Service Temperature • Max = 220° • Min = Already below Tg
Cellulosic • Material Suppliers • Albis • Eastman • Kleer • Rotuba