PLASTIC TYPES

Plastic are conveniently divided into two main type:

i - Thermoplastic - Material which are processed under the influence of heat and pressure, retain thioer moulded form when cold but can be resoftened by heat and indefinite nunber of times (barring degredation by excessing reprocessing).



ii - Thermosetting - Materials which are processed under the influence of heat and
pressure, retain thier moulded form when hot and cannot therefore be resoftened by heat. The thermosettng condition is reached by chemical reaction during processing.