Polyesters, TP

The popular thermoplastic polyesters are polybutylene terephthalate (PBT) and polyethylene terephthalate (PET). TP polyesters are in a family of polyesters that has widely varying and important range of properties. There are the two major groups of the TPs (with comparatively high melting points) and the TSs (which are usually typified by a cross-linked structure). TP polyesters are often called saturated polyesters to distinguish them from unsaturated polyesters that are the TSs. 

PET matrix in a glass fiber mat TP sheet molding material is produced. A 40 wt% glass-reinforced PET was used by Chrysler for the four exterior body panels of its experimental Compact Concept car (with the comment that it would be possible to produce the resin matrix by chemically recycling waste drinking bottles). 

PBT is used as a matrix material for RPs, with its crystallization offering high rigidity and tensile strength, low polarity giving high dimensional 

Applications include all-plastic windscreen wiper systems, where it has been possible to integrate parts and reduce the complexity of the component (and eliminate the need for painting), with 30% and 50% glass-reinforced PBTs. Other potential appUcations include housings for door mirrors and headlamps. 

Also called polythene. Representing the largest used plastic with very little using reinforcements, PEs are of the olefin family with many different formulations [US consumption HDPE 42 wt%, LLDPE 27%, LDPE 20%, EVA 4%, others (VLDPE, MDPE, UHMWPE, etc.) 7%]. By far the largest volumes of these unreinforced materials go into film 

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Note The principal reinforcement, with respect to quantity, is glass fibers, but many other types are used (cotton, rayon, polyester/TP, nylon, aluminum, etc.). Of very limited use because of their cost and processing difficulty are whishers (single crystals of alumina, silicon carbide, copper, or others), which have superior mechanical properties. 

Part of the polyolefin family are PBs. They are similar to PPs and HDPEs but exhibit a more crystalline structure. This crystallinity produces unusual high strength and extreme resistance to deformation over a temperature range of-10 to 190F. Its structure results in a rubberlike, elastomeric material with low molded-in stress. Tensile stress that does not plateau after reaching its yield point makes possible films that look like PE but act more like polyester (TP) films. Compared to other polyolefins, they have superior resistance to creep... 

Polyester TP/Glass Polymethylpentene Polycarbonate Copolymer Polypropylene/Glass... 

Here they have made many major contributions to the contemporary scene. Health-care professionals depend on plastics for everything from intravenous bags to wheelchairs, disposable labware to silicone body parts, and so on. The diversity of plastics allows them to serve in many ways, improving and prolonging lives [such as a braided, corrugated (Du Font s Dacron polyester) TP aorta tube]. 

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