Phenolics are strong, brittle, good electrical insulators and can withstand temperatures up to 150 deg. C. Phenolics are destroyed by strong alkalis and oxidising agents. Phenolics are generally dark in colour. 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.
Amino Plastic -UF..Urea FormaldehydeMouldings 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 FormaldehydeHarder 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.
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.
