Types, properties and applications of thermoplastic materials Types, properties and applications of thermoset materials Structure of plastics Plastic monomers
There are two kinds of polyesters that each lead to thermoplastic or thermosetting products. The difference between the two kinds of polyester is their chemical structures. Thermoplastic polyester, like PET, is made from polymerization (polycondensation) of diacids (HOOC-R-COOH) and dialcohol (HO-R’-OH), producing linear chain macromolecules of polyesters and water. This kind of polyesters are used as synthetic fibers as well as plastic parts. Whereas, in thermosetting unsaturated polyesters, diacids are reacting with multifunctional alcohols, like glycerin, and monomers including unsaturated bonds. Thus, macromolecular chains grow in a 3D network with production of chemical crosslinks between chains. The resulting structure is not linear, but a 3-dimensional network. Because of this 3D network, this kind of polyester does not melt when heated, is cured and permanently remains solid. They are not used alone, are sued as a matrix (continuous) phase with reinforcing fibers and particulate materials. I hope its clear now.
Dear sir, I want you to give a lecture on making a thermoplastic mask, which is used in in the area of medical health specially used while performing the radiotherapy to the patient suffering with cancer.
