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Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Chapter 3Engineering Plastics,Engineering Thermoplastics,Replace metallic parts,Strength and stiffness,Retention of properties over range of temperatures,Toughness to withstand incidental damage,Dimensional stability,Low creep,Low CTE,Withstand environmental factors (UV, O,2, chemicals),Shaped easily,Engineering Thermoplastics,Compared to commodity plastics,More expensive,The commodity resins are all lacking some critical property,Some Engineering Thermoplastics are formed through the condensation polymerization process,Polyamides or Nylons (PA),Nylon History,PA is considered the first engineering thermoplastic,PA is one of many heterochain thermoplastics, which has atoms other than C in the chain.,PA invented in 1928 by Wallace Carothers, DuPont, in search of a “super polyester fiber with molecular weights greater than 10,000. First commercial nylon in 1938.,PA was created when a condensation reaction occurred between amino acids, dibasic acids, and diamines.,Nylons are described by a numbering system which indicates the number of carbon atoms in the monomer chains,Amino acid polymers are designated by a single number, as nylon 6,Diamines and dibasic acids are designated with 2 numbers, the first representing the diamine and the second indicating the adipic acid, as in nylon 6,6 or nylon 6,10 with sebacic acid.,( ),n, ,a, ,b,Polyamides or Nylons (PA), ,a, ,b,Structure of PA,Hydrogen bond in PA,Hydrogen bonding (orange arrows) between oxygen atoms on one polymer mainchain and hydrogen atoms attached to nitrogen atoms on an adjacent polymer mainchain help to give nylon its strength.,Properties of Nylons,Mechanical Properties of Polyamides,Physical Properties of Polyamide,Advantages Disadvantages of Polyamide,Advantages,Tough, strong, impact resistant,Low coefficient of friction,Abrasion resistance,High temperature resistance,Processable by thermopalstic methods,Good solvent resistance,Resistant to bases,Disadvantages,High moisture absorption with dimensional instability,loss of up to 30 % of tensile strength and 50% of tensile modulus,Subject to attack by strong acids and oxidizing agents,Requires UV stabilization,High shrinkage in molded sections,Electrical and mechanical properties influenced by moisture content,Dissolved by phenols,Additives and Reinforcements to PA,Additives- antioxidants, UV stabilizers, colorants, lubricants,Fillers,Talc,Calcium carbonate,Reinforcements,Glass fiber- short fiber (1/8 or long fiber 1/4),Mineral fiber (wolastonite),carbon fibers,graphite fibers,metallic flakes,steel fibers,Properties of Reinforced Nylon,Nylon 6,6,Hexamethylenediamine,(6 carbons),Nylon 6,6,Adipic Acid,(6 carbons),Nylon 6,6,Water,Nylon 6,6,Nylon 6,Amine,Group,Acid,Group,Nylon 6,Water,Properties of Specific Nylon Types,Nylon 6,6 General,Nylon 6 Copycat,Nylon 6,10 Less water absorption,Nylon 6,12 Flexibility and less water,Nylon 2,2 Strength,Processing of Nylon,Injection molding,Shrinkagecrystallinity.018 in/in,Dry it first,Extrusion,Low melt viscosity,Be careful of decomposition,Fibers,Drawing,Crystallization,Orientation,Applications for Polyamides,Fiber applications,50% into tire cords (nylon 6 and nylon 6,6),rope, thread, cord,belts, and filter cloths.,Monofilaments- brushes, sports equipment, and bristles (nylon 6,10),Plastics applications,bearings, gears, cams,rollers, slides, door latches, thread guides,clothing, light tents, shower curtains, umbrellas,electrical wire jackets (nylon 11),Adhesive applications,hot melt or solution type,thermoset reacting with epoxy or phenolic resins,flexible adhesives for bread wrappers, dried soup packets, bookbindings,Aramids,Aramids,Aramid fiber,Polycarbonate,PC Background,PC was invented in 1898 by F. Bayer in Germany,Commercial production began in the US in 1959.,Amorphous, engineering thermoplastic that is known for toughness, clarity, and high-heat deflection temperatures.,Polycarbonates are linear, amorphous polyesters because they contain esters of carbonic acid and an aromatic bisphenol.,Polycarbonate,(,),n,Synthesis,Properties,Mechanical Properties of Acrylic, PC, PC/ABS,Physical Properties of Acrylic, PC, PC/ABS,Applications for PC,PC,(high impact strength, transparency, excellent creep and temperature),lenses, films, windshields, light fixtures, containers, appliance components and tool housings,hot dish handles, coffee pots, popcorn popper lids, hair dryers.,Pump impellers, safety helmets, beverage dispensers, trays, signs,aircraft parts, films, cameras, packaging,Acetals or Polyoxymethylenes (POM),Acetals or Polyoxymethylenes (POM),(,),n,History,Polyacetal or Polyoxymethylene (POM),Polymerized from formaldehyde gas,First commercialized in 1960 by Du Pont,Similar in properties to Nylon and used for plumbing fixtures, pump impellers, conveyor belts, aerosol stem valves, VCR tape housings,A kind of heterochain polymers,Synthesis,Acetal General Family Characteristics,Mechanicaldo not embrittle, good impact strength,Moisturevery little (shower heads),Chemical resistancevery high, resists stains, sensitive to strong acids and bases,Weatheringfair,Thermal200,o,F,Electricalgood,Machininglike cutting brass,Adhesionepoxy glues,Acetal Copolymer,Celcon (Celanese),Properties,Mechanical Properties Comparison,Processing Acetals,Do not heat above,226,o,C,Melt viscosity is not too dependant on temperature,Acetal (POM),Advantages,Easy to fabricate, has glossy molded surfaces, provide superior fatigue endurance, creep resistance, stiffness, and water resistance.,Among the strongest and stiffest thermoplastics.,Resistant to most chemicals, stains, and organic solvents,Disadvantages,Poor resistance to acids and bases and difficult to bond,Subject to UV degradation and is flammable,Toxic fumes released upon degredation,Acetal (POM),Applications,Bearings,Bushings,(轴衬),Valve seats,Washers,(垫圈),Nozzles,Spool,s(缠绕筒),Cams,(凸轮),Polyphenylene oxide (PPO),Poly(phenylene ether),Synthesis,PPO Properties,Thermal stabilityexcellent (,343,o,C,),High HDT =,190,o,C,Good cold properties (,-170,o,C,),Low water absorption,Low heat expansion,Good solvent resistance, but can be solvent welded,PPO Properties,Noryl is a PPO blend with polystyrene,PPO,Advantages of PPO,Good fatigue and impact strength,Good radiation resistance,Excellent dimensional stability,Low oxidation,Disadvantages of PPO,High cost,Poor resistance to certain chemicals,Modified PPO (Noryl),1. PPO/PS,2. PPO/PA,3. PPO/PPS,4. PPO/PBT,5. PPO/ABS,PPO uses,Used to replace stainless steel for surgical equipment,Replace thermosets,Pump housings,Valve components,Video terminal housings,Thermoplastic Polyesters (PET/PBT),Polyester History,1929 W. H. Carothers suggested classification of polymers into two groups,condensation,and,addition,polymers.,Carothers was not successful in developing polyester fibers from linear aliphatic polyesters due to low melting point and high solubility. No commercial polymer is based on these.,p-phenylene group is added for stiffening and leads to polymers with high melting points and good fiber-forming properties, e.g., PET.,Polymers used for films and for fibers,Polyesters is one of many heterochain thermoplastics, which has atoms other than C in the chain.,Polyesters includes unsaturated (,thermosets,), saturated and aromatic,thermoplastic,polyesters.,Thermoplastic Polyesters (PET/PBT),Synthesis,Thermoplastic Polyester General Family Characteristics,PET,Higher mechanical stiffness,Strength by orienting chains not by H-bonding,Get 50% crystallinity,forced by mechanical stretching,PBT,crystallizes rapidly,processes faster,lower overall properties,PET Chemical Structure and Applications,The flexible, but short, (CH,2,),2,groups tend to leave the chains relatively stiff and PET is notes for its very slow crystallization. If cooled rapidly from the melt to a Temp below Tg, PET solidifies in amorphous form.,If PET is reheated above Tg, crystallizaiton takes place to up to 30%.,In many applications PET is first pre-shaped in amorphous state and then given a uniaxial (fibers or tapes) or biaxial (film or containers) crystalline orientation.,During Injection Molding PET can yield amorphous transparent objects (Cold mold) or crystalline opaques objects (hot mold),PBT Chemical Structure and Applications,The longer, more flexible (CH,2,),4,groups allow for more rapid crystallization than PET.,PBT is not as conveniently oriented as PET and is normally injection molded.,PBT has a sharp melting transition with a rather low melt viscosity.,PBT has rapid crystallization and high degree of crystallization causing warpage concerns,PBT has lower melting point than PET which allows easier fabrication of PBT.,Thermoplastic Aromatic Copolyesters,Polyarylesters,Repeat units feature only aromatic-type groups (phenyl or aryl groups) between ester linkages.,Called wholly aromatic polyesters,Based on a combination of suitable chemicals,p-hydroxybenzoic acid,terephthalic acid,isophthalic acid,bisphenol-A,Properties correspond to a very stiff and regular chain with high crystallinity and high temperature stability,Applications include bearings, high temperature sensors, aerospace applications,Processed in injection molding and compression molding,Most thermoplastic LCP appear to be aromatic copolyesters,Advantages and Disadvantages of Polyesters,Advantages,Tough and rigid,Processed by thermoplastic operations,Recycled into useful products as basis for resins in such applications as sailboats, shower units, and floor tiles,PET flakes from PET bottles are in great demand for fiberfill for pillows and sleeping bags, carpet fiber, geo-textiles, and regrind for injection and sheet molding,PBT has low moisture absorption,Disadvantages,Subject to attack by acids and bases,Low thermal resistance,Poor solvent resistance,Must be adequately dried in dehumidifier prior to processing to prevent hydrolytic degradation.,Thermoplastic Copolyesters,Copolyester is applied to those polyesters whose synthesis uses more than one glycol and/or more than one dibasic acid.,Copolyester chain is less regular than monopolyester chain and as a result has less crystallinity,PCTA copolyester (Poly cyclo-hexane-dimethanol-terephthalate acid) amorphous,Reaction includes cyclohexanedimethanol and terephthalic acid with another acid substituted for a portion of the terephthalic acid,Extruded as transparent film or sheets that are suitable for packaging applications (frozen meats shrink bags, blister packages, etc.),Glycol-modified PET (PETG) amorphous,Blow-molded containers, thermoformed blister packages.,Specific TP Polyester Types,Dacron fibermix with cotton or wool-gives permanent creases,Kodel photo film,Mylartransparencies, tapes,PETGglycol modified, amorphous, like PVC,Properties of PET,Properties of PBT,Mechanical Properties of Polyesters,Physical Properties of Polyester,Processing PET,Shape it (film, tape, fiber, extrude, etc),Amorphous structure,Reheat and stretch in strength direction(s),Cool to below T,g,Applications for Polyesters (PET),Blow molded bottles,100% of 2-liter beverage containers and liquid products,Fiber applications,25% of market in tire cords, rope, thread, cord, belts, and filter cloths.,Monofilaments- brushes, sports equipment, clothing, carpet, bristles,Tape form- uniaxially oriented tape form for strapping,Film and sheets,photographic and x-ray films; biaxial sheet for food packages,Molded applications- Reinforced PET,Rynite, Valox, Impet,luggage racks, grille-opening panels, functional housings such as windshield wiper motors, blade supports, and end bells,sensors, lamp sockets, relays, switches, ballasts, terminal blocks,Appliances and furniture,oven and appliance handles, coil forms for microwaves, and panels,- pedestal bases, seat pans, chair arms, and casters,Applications for Polyesters (PBT and LCP),PBT - 30 M lbs in 1988,Molded applications (PBT),Valox, Xenoy, Vandar, Pocan,distributers, door panels, fenders, bumper fascias,automotive cables, connectors, terminal blocks, fuse holders and motor parts, distributor caps, door and window hardware,Extruded applications,extrusion-coat wire,extruded forms and sheet produced with some difficulty,Electronic Devices (LCP),26 M lbs Terylene, Dacron, Kodel,fuses, oxygen and transmission sensors,chemical process equipment and sensors,coil,Acrylics (PAN, PMMA),Acrylics (PAN, PMMA),(,),n,(,),n,Properties,Color (transparency)20 years w/ 10% change,Weatheringbest,Mechanical propertiesaverage except for impact (brittle),Chemicalchlorinated solvents attack it, acetone gives it cracks,Electricalgood,Uses,Signs,Counter topsCorian,Decorative pieces,Floor waxes,Paint, fingernail polishes,Contact lenses, glasses,Processing,Casting (sheets)syrup,Injection moldinggood,Thermoformingok but brittle,Machiningsimilar to wood,High Performance Engineering Plastics,Polyimide (PI),Polyphenyl sulfide (PPS),Polysulfone (PSU),Poly arylether ketone (PAEK),Fluoropolymers, Polytetrafluoroethylene (PTFE),Thermoplastic Polyimides (PI and PAI),Thermoplastic Polyimides (PI and PAI),(,),n,),n,(,Synthesis of polyamide imide,Properties,Very stiff,Highest thermal stability,PI cannot be melted or melt processed,PAI can be (Torlon),PI is sintered (Vespel),PI film is cast as monomers and heated to polymerize (Kapton),Manufacturing of polyimide film,Uses,PI is used in circuit boards,High temperature parts,Low friction bearings, sliding parts,Gears,Polyimide Application,Polyphenyl sulfide (PPS),Synthesis of PPS,Properties,PPO and PPS Materials,*,Advantages of PPS *Advantages of PPO,- Usage Temp at 450F - Good fatigue and impact strength,- Good radiation resistance - Good radiation resistance,- Excellent dimensional stability - Excellent dimensional stability,- Low moisture absorption - Low oxidation,- Good solvent and chemical resistance,- Excellent abrasion resistance,*Disadvantages of PPS *Disadvantages of PPO,- High Cost - High cost,- High process temperatures -Poor resistance to certain chemicals,- Poor resistance to chlorinated hydrocarbons,PPO and PPS Applications,*,PPS Applications*PPO Applications,- Computer components - Video display terminals,- Range components - Pump impellers,- Hair dryers - Small appliance housings,- Submersible pump enclosures - Instrument panels,- Small appliance housings - Automotive parts,PPS and PPO Mechanical Properties,PPS and PPO Physical Properties,PPS and PPO Processing Properties,PPS frequently has glass fibers loaded up to 40% by weight,Tensile strength = 28 kpsi, tensile modulus = 2 Mpsi, HDT = 500F,PPO is frequently blended with PS over a wide range of percentages.,(Noryl from G.E.),Polysulfones (PSU and PES),Polysulfones (PSU and PES),Structures,Union Carbide Co.,Properties,Resistant to oils,Heat stability (300,o,F),Creep resistance,SO,2,group adds stiffness,More dimensionally stable than PPO,Toughnessgood,Outstanding impact resistance,Commercially available polysulfones,Uses,Hot water pipes,Coffee pots,Dishwasher components,Automobile applications near engines,Compete with thermosets, but can be injection molded,Polyaryletherketones (PEEK, PEK, and Others),Polyaryletherketones (PEEK, PEK, and Others),Ether Linkage,Ketone Linkage,PEEK History,Polyether-ether-ketone (PEEK) and Polyether ketone (PEK),PEEK invented by ICI in 1982. PEK introduced in 1987,PEEK and PEK are aromatic polyketones,Volume for polyketones is 500,000 lbs per year in 1990. Estimated to reach 3 to 4 million by 2000.,Cost is $30 per pound (as of October 1998),Product Names,ICI: Vivtrex,BASF: Ultrapak,Hoechst Celanese: Hostatec,DuPont: PEKK,Amoco: Kadel,Chemical Structure,PEEK- Poly-ether-ether-ketone,PEK- Poly-ether-ketone,Chemical Synthesis,Synthesis of polyketones,PEK,: Formation of the,carbonyl,link by polyaroylation from low cost starting materials. Requires solvents such as liquid HF. Excessive solvents and catalyst cause the high material cost.,PEEK,: Formation of,ether,link using phenoxide anions to displace activated halogen.,Mechanical Properties of PEEK,Physical Properties of PEEK,Properties of Reinforced PEEK,Processing Properties of PEEK,Advantages and Disadvantages of Polyketones,Advantages,Very high continuous use temperature (480,F),Outstanding chemical resistance,Outstanding wear resistance,Excellent hydrolysis resistance,Excellent mechanical properties,Very low flammability and smoke generation,Resistant to high levels of gamma radiation,Disadvantages,High material cost,High processing temperatures,PEEK and PEK Applications,Aerospace: replacement of Al,Fuel line brakes to replacement of primary structure,Electrical,wire coating for nuclear applications, oil wells, flammability-critical mass transit.,Semi-conductor wafer carriers which can show better rigidity, minimum weight, and chemical resistance to fluoropolymers.,Other applications,Chemical and hydrolysis resistant valves (replaced glass),Internal combustion engines (replaced thermosets),Cooker components (replaced enamel),Automotive components (replaced metal),High temperature and chemical resistant filters from fiber,Low friction bearings,Flouropolymers (PTFE, FEP, PFA),Flouropolymers (PTFE, FEP, PFA),),n,),n,(,(,History of Discovery,Dr. Roy Plunkett, a young scientist working at DuPont, accidentally discovers polytetrafluoroethylene (PTFE), an inherently slippery and remarkably chemically resistant plastic. It is said to be the most slippery substance on earth. The initial discovery occurred in 1938, but the commercial introduction of DuPonts Teflon,did not occur until 1946.,Teflon,is most widely known for its widespread use in nonstick cookware and as cable insulation but it is used in a wide variety of other unique applications. Teflon,sheet is used as an insulator and lubricant between the copper skin and the stainless steel skeleton of the Statue of Liberty. It is also widely used for specialty textiles. The roof of the Pontac Silverdome is made of a Teflon,coated woven glass fiber fabric.,Properties,Most are strengthened by the tight bond between the Fluorine and the Carbon atoms,Slip
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