ABS (AcronitrileButedeneStyrene
Tough, stiff, abrasive resistant and can be metal plated. Good stain resistance but are attacked by chlorinated solvents, esters, keytones and concentrated acids and alkalis. Some greases can cause stress cracking. The properties of ABS depend on the proportions of the three constituents. . ABS can be injection moulded, extruded, rotationally moulded and thermoformed. Typical applications include boat hulls, telephones, piping/fittings, and domestic durables.
Tough, stiff, abrasive resistant and can be metal plated. Good stain resistance but are attacked by chlorinated solvents, esters, keytones and concentrated acids and alkalis. Some greases can cause stress cracking. The properties of ABS depend on the proportions of the three constituents. . ABS can be injection moulded, extruded, rotationally moulded and thermoformed. Typical applications include boat hulls, telephones, piping/fittings, and domestic durables.
(Plasticised) PVC (PolyVinylChloride
Flexibility and properties depend on the nature and content of plasticisers. Used for cable/wire insulation, soles of footwear, and coating linen liners of industrial gloves.
Flexibility and properties depend on the nature and content of plasticisers. Used for cable/wire insulation, soles of footwear, and coating linen liners of industrial gloves.
(UnPlasticised) UPVC (PolyVinylChloride
Hard/tough/ strong and stiff with good weathering properties. It is weather resistant and self extinguishing, can be transparent and the surface is scuff and abrasion resistant. UPVC. UPVC can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed. It is mostly used for making pipe/pipe fittings, bottles, and curtain rails.
Hard/tough/ strong and stiff with good weathering properties. It is weather resistant and self extinguishing, can be transparent and the surface is scuff and abrasion resistant. UPVC. UPVC can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed. It is mostly used for making pipe/pipe fittings, bottles, and curtain rails.
Polyethylene
Tough at low temperatures with excellent chemical and electrical insulation properties. Detergents can cause stress cracking. Can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed. LDPE- Low Density Polyethylene(918-935 kg/m3 is very tough and flexible with excellent chemical resistance. Used for pipes and low loss electrical wire coverings. HDPE- High Density Polyethylene (935- 965 kg/m3 is much stronger and stiffer. It is used for tanks, pipes dustbins etc.
Tough at low temperatures with excellent chemical and electrical insulation properties. Detergents can cause stress cracking. Can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed. LDPE- Low Density Polyethylene(918-935 kg/m3 is very tough and flexible with excellent chemical resistance. Used for pipes and low loss electrical wire coverings. HDPE- High Density Polyethylene (935- 965 kg/m3 is much stronger and stiffer. It is used for tanks, pipes dustbins etc.
Polypropylene
Excellent fatigue resistances, chemical and electrical properties. Good temperature resistance and useful strength and stiffness. It is attacked by strong oxidising agents. Can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed.
Excellent fatigue resistances, chemical and electrical properties. Good temperature resistance and useful strength and stiffness. It is attacked by strong oxidising agents. Can be extruded, injection moulded, blow moulded, rotationally moulded and thermoformed.
AMORPHOUS THERMOPLASTICS
Acrylics
Completely transparent and optically clear. Stable to outdoor weathering and do not discolour or degrade under UV light. Acrylics are stiff, strong and do not shatter. Some solvents can cause stress cracking.
Acrylics can be extruded, injection moulded, and thermoformed. The are used for viewing panels, light housings, lenses and illuminated signs.
Completely transparent and optically clear. Stable to outdoor weathering and do not discolour or degrade under UV light. Acrylics are stiff, strong and do not shatter. Some solvents can cause stress cracking.
Acrylics can be extruded, injection moulded, and thermoformed. The are used for viewing panels, light housings, lenses and illuminated signs.
Polycarbonates
Tough, transparent, stiff and strong. Good electrical insulation properties. Polycarbonates have moderate outdoor weather resistance. Dissolved by chlorinated paraffins, cresol,dioxane. Attacked by hydrocarbons. Polycarbonates can be injection moulded, extruded, blow moulded, and vacuum formed. Typical applications include street lamp covers, safety helmets.
Tough, transparent, stiff and strong. Good electrical insulation properties. Polycarbonates have moderate outdoor weather resistance. Dissolved by chlorinated paraffins, cresol,dioxane. Attacked by hydrocarbons. Polycarbonates can be injection moulded, extruded, blow moulded, and vacuum formed. Typical applications include street lamp covers, safety helmets.
Polysulphones
Strong, stiff with excellent creep and dimensional properties over a wide range of temperatures. Can be transparent. They do not easily burn and do not present a smoke hazard. They are attacked by ketones chlorinated solvents and hydrocarbons. They can be extruded, injection moulded and thermoformed. Polysulphanes are used for passenger service units in aircraft and electrical components requiring high service temperatures.
Strong, stiff with excellent creep and dimensional properties over a wide range of temperatures. Can be transparent. They do not easily burn and do not present a smoke hazard. They are attacked by ketones chlorinated solvents and hydrocarbons. They can be extruded, injection moulded and thermoformed. Polysulphanes are used for passenger service units in aircraft and electrical components requiring high service temperatures.
CRYSTALLINE THERMOPLASTICS
Nylon...Polyamines
Nylon materials are stiff, strong,tough and abrsion resistant. Absorption of moisture increases toughness, decreases stiffness and affects dimensional stability. Concentrated mineral acid attacks nylon. Nylon can be injection moulded, rotationally moulded and extruded. Applications for nylons include insulators, and engineering components such as gears, bushes, and bearings. Glass filled nylon is used to make power tool housings etc.
Nylon materials are stiff, strong,tough and abrsion resistant. Absorption of moisture increases toughness, decreases stiffness and affects dimensional stability. Concentrated mineral acid attacks nylon. Nylon can be injection moulded, rotationally moulded and extruded. Applications for nylons include insulators, and engineering components such as gears, bushes, and bearings. Glass filled nylon is used to make power tool housings etc.
Polyacetals..
Stiff, strong, resist high temperatures and are extremely resilient. These materials are abrasion resistant and have low coefficient of friction. Polyacetals are attacked by strong acids. Applications include pipe fittings, light-duty beam springs, meat hooks, gears, bearings etc.
Stiff, strong, resist high temperatures and are extremely resilient. These materials are abrasion resistant and have low coefficient of friction. Polyacetals are attacked by strong acids. Applications include pipe fittings, light-duty beam springs, meat hooks, gears, bearings etc.
Thermoplastic Polyester.
This material has similar physical properties to nylon 66 but have much lower moisture absorption. Is attacked by ethylene dichloride and is susceptible to hydrolysis in prolonged contact with hot water. Processed by injection moulding.
This material has similar physical properties to nylon 66 but have much lower moisture absorption. Is attacked by ethylene dichloride and is susceptible to hydrolysis in prolonged contact with hot water. Processed by injection moulding.
PTFE..Polytetrafluoroethylene.
PTFE resists all common aggressive environments, has exceptional low coefficient of friction, first class electrical properties and can be used at temperatures up to 250 deg C. It can be processed only be a special sintering techniques. Complicated shapes are generally machined from sintered blanks. PTFE is used for bearings, bearing surfaces treatments, high frequency cable insulation, coating for cooking utensils etc etc.
PTFE resists all common aggressive environments, has exceptional low coefficient of friction, first class electrical properties and can be used at temperatures up to 250 deg C. It can be processed only be a special sintering techniques. Complicated shapes are generally machined from sintered blanks. PTFE is used for bearings, bearing surfaces treatments, high frequency cable insulation, coating for cooking utensils etc etc.
Thermosets
Phenolics
Phenolics are strong, brittle, good electrical insulators and can temprtures up to 150 deg. C. Phenolics are destroyed by strong alkalis and oxidising agents. Phenolics are generally dark in color. Fibrous fillers are often used to improve impact strength and lower specific costs. Mica fillers are used to improve electrical properties. Phenolics are used for electrical plugs, switches, knobs and general electrical fittings. Fabric laminates are used for engineering applications such as gears.
Phenolics are strong, brittle, good electrical insulators and can temprtures up to 150 deg. C. Phenolics are destroyed by strong alkalis and oxidising agents. Phenolics are generally dark in color. Fibrous fillers are often used to improve impact strength and lower specific costs. Mica fillers are used to improve electrical properties. Phenolics are used for electrical plugs, switches, knobs and general electrical fittings. Fabric laminates are used for engineering applications such as gears.
Amina Plastic -UF..Urea Formaldehyde
Mouldings are low cost and have good hardness, abrasion and chemical resistance. They do not taint foodstuffs, have heat resistance to about 70 deg C and are available in a wide range of colours. Wood flour is normally used as a filler for darker material and cellulose is used for lighter compounds. Used for domestic plastics e.g toilet seats. UF foam is used for cavity wall insulation applications.
Mouldings are low cost and have good hardness, abrasion and chemical resistance. They do not taint foodstuffs, have heat resistance to about 70 deg C and are available in a wide range of colours. Wood flour is normally used as a filler for darker material and cellulose is used for lighter compounds. Used for domestic plastics e.g toilet seats. UF foam is used for cavity wall insulation applications.
Aminoplastic -MF..Melamine Formaldehyde
Harder than UF and absorb less moisture. MF compounds have good heat and stain resistance. Generally used for domestic table ware. Glass reinforced laminates have a heat resistance up to 200 deg. C.
Harder than UF and absorb less moisture. MF compounds have good heat and stain resistance. Generally used for domestic table ware. Glass reinforced laminates have a heat resistance up to 200 deg. C.
Polyesters.
Unsaturated polyesters have a resistance to UV, water, acids, alkalis and many organic solvents. They have fairly good electrical properties. They are usually reinforced with fibres mostly in the form of woven cloth, chopped strand mat, or short fibres. Large mechanical structures can be made for Reinforced Polyester material with stiffness of up o 10 times that of thermoplastics. Applications for reinforced polyester materials include roof sheeting, car bodies, tanks, boat hulls etc.
Unsaturated polyesters have a resistance to UV, water, acids, alkalis and many organic solvents. They have fairly good electrical properties. They are usually reinforced with fibres mostly in the form of woven cloth, chopped strand mat, or short fibres. Large mechanical structures can be made for Reinforced Polyester material with stiffness of up o 10 times that of thermoplastics. Applications for reinforced polyester materials include roof sheeting, car bodies, tanks, boat hulls etc.
Epoxides
Epoxides are more expensive than unsaturated polyesters. They are tough and have extremely good resistance to alkalis. They adhere well to many materials and shrink little during curing. Epoxides are used to encapsulate electronic components. Glass-reinforced epoxides are used in chemical plants.
Epoxides are more expensive than unsaturated polyesters. They are tough and have extremely good resistance to alkalis. They adhere well to many materials and shrink little during curing. Epoxides are used to encapsulate electronic components. Glass-reinforced epoxides are used in chemical plants.
Rubbers and Elastomers
Natural Rubber NR.. (Hevea, rubber, natural cis-polyisoprene)
A general purpose rubber with the optimum balance of physical properties essential for high performance engineering applications. Long fatigue life, first choice for spring applications. Has high strength without the need for reinforcing fillers. Can be compounded to give a wide range of hardness. Good low temperature flexibility Poor resistance to oils and solvents. Requires protection against oxidisation, ozone and heat. It can be extended by oil with little loss of mechanical properties.
A general purpose rubber with the optimum balance of physical properties essential for high performance engineering applications. Long fatigue life, first choice for spring applications. Has high strength without the need for reinforcing fillers. Can be compounded to give a wide range of hardness. Good low temperature flexibility Poor resistance to oils and solvents. Requires protection against oxidisation, ozone and heat. It can be extended by oil with little loss of mechanical properties.
Isoprene Rubber(IR) .. (synthetic cis-polyisoprene)
Very similar properties to natural rubber but more difficult to process.
Very similar properties to natural rubber but more difficult to process.
Styrene Butadiene Rubber (SBR)
The most important general purpose synthetic rubber. It must be compounded with reinforcing fillers for high strength and then has physical and chemical properties similar to natural rubber, except that generally abrasion resistance is better and fatigue resistance is pooer. It is not suitable for springs but has used widely for vehicle tyres where it is generally oil extended.
The most important general purpose synthetic rubber. It must be compounded with reinforcing fillers for high strength and then has physical and chemical properties similar to natural rubber, except that generally abrasion resistance is better and fatigue resistance is pooer. It is not suitable for springs but has used widely for vehicle tyres where it is generally oil extended.
Butadiene Rubber (BR)
Low hysteresis, good temperature flexibility and high abrasion resistance under severe weather conditions. Poor processing properties and poor tear properties. Used in blends with SBR and natural rubber. Main use in in manufacture of tyres.
Low hysteresis, good temperature flexibility and high abrasion resistance under severe weather conditions. Poor processing properties and poor tear properties. Used in blends with SBR and natural rubber. Main use in in manufacture of tyres.
EPM Rubber (EPM) ..(ethylene propylene copolymer)+ EPDM Rubber (EPDM) ..(ethylene propylene terpolymer). Similar to SBR but improved resistance to atmostpheric ageing, oxidisation, and ozone. Not compatable with elastomers listed above.
Butyl Rubber (BUTYl) ..(isombutylene-isoprene copolymer)
Good ozone, weathering, heat and chemical resistance. It has a very high impermeability to gases. Low resilience at ambient temperatures and is suitable for damping applications. Incompatible with elastomers listed above. Can be compounded with chlorine to give improved ozone, weathering resistance and high temperature stability. Used for inner tubes.
Good ozone, weathering, heat and chemical resistance. It has a very high impermeability to gases. Low resilience at ambient temperatures and is suitable for damping applications. Incompatible with elastomers listed above. Can be compounded with chlorine to give improved ozone, weathering resistance and high temperature stability. Used for inner tubes.
Chloroprene Rubber (CR)...Neoprene..
Several types of polychloroprene. Mechanical properties generally inferior to natural rubber but superior chemical properties. Over time crystallisation results in hardening at temperatures about -10 deg. C. Very good resistance to ozone.
Several types of polychloroprene. Mechanical properties generally inferior to natural rubber but superior chemical properties. Over time crystallisation results in hardening at temperatures about -10 deg. C. Very good resistance to ozone.
Nitrile Rubber (Acrylonitrile Butediene copolymer).
Nitrile rubbers are copolymers of butadiene and acrylonitrile. The oil resistance increases as the acrylonitrile content but at the expense of resilience. Used for O rings and oil seals.
Nitrile rubbers are copolymers of butadiene and acrylonitrile. The oil resistance increases as the acrylonitrile content but at the expense of resilience. Used for O rings and oil seals.
Polysulphide Rubber (TR) Thiokol (condensates of sodium polysulphides with organic dihalides.)
Excellent high resistance to oils, fuels , solvents, oxygen and also low gas permeability. Poor physica,heat, and wear properties.
Excellent high resistance to oils, fuels , solvents, oxygen and also low gas permeability. Poor physica,heat, and wear properties.
Polyurethane Rubber (AU - Polyester type...EU- Polyether type)
Good abrasion, tensile and tear strength, good resistance to aliphatic solvents and mineral oils, oxygen and ozone. Moderate resistance to dry heat. Poor resistance to moist heat.
Good abrasion, tensile and tear strength, good resistance to aliphatic solvents and mineral oils, oxygen and ozone. Moderate resistance to dry heat. Poor resistance to moist heat.
Silicone rubber
Moderate physical properties but are retained at high or low temperatures. Good electrical properties.
Moderate physical properties but are retained at high or low temperatures. Good electrical properties.
Chlorosulphonyl Polytethylene ..(Hypolon)
Excellent resistance to oxygen, ozone, and most chemicals. Low gas permeability. Used for protective coatings.
Excellent resistance to oxygen, ozone, and most chemicals. Low gas permeability. Used for protective coatings.
Fluoro Rubbers (Fluorel, Kel-F, Viton)
Excellent resistance to strong oxidising acids, aromatic fuels and solvents at high temperatures, and to oxidation weathering and ozone.
Excellent resistance to strong oxidising acids, aromatic fuels and solvents at high temperatures, and to oxidation weathering and ozone.
Acrylic Rubber (AR) (Alkyl acrylate coplolymer).
Good resistance at normal and elevated temperatures to oil and oxygen. Excellent ozone and and weathering resistance. Poor moist heat resistance.
Good resistance at normal and elevated temperatures to oil and oxygen. Excellent ozone and and weathering resistance. Poor moist heat resistance.
Epichlorohydrin (CO)..
High resistance to ageing oxidatio, ozone and hot oil. Good resistance to hydrocarbon solvents combined with moderate low temperature flexibility, poor abrasion resistance and electrical properties.
High resistance to ageing oxidatio, ozone and hot oil. Good resistance to hydrocarbon solvents combined with moderate low temperature flexibility, poor abrasion resistance and electrical properties.
Polypropylene oxide rubber(PO).. (a copolymer with about 5% allyl glycol ether)
Similar to SBR in requiring reinforcing fillers for adequate strength. Good resistance to ozone, flexing and heat ageing. Good low temperature flexibility; moderate oil resistance. properties.
Similar to SBR in requiring reinforcing fillers for adequate strength. Good resistance to ozone, flexing and heat ageing. Good low temperature flexibility; moderate oil resistance. properties.
No comments:
Post a Comment