Thermoplastics liquid crystal polymer

POLYMER COMPOSITES AND POLYMER LIQUID CRYSTAL + THERMOPLASTIC BLENDS... 

At least two good ways out exist. One consists of the dispersion at the molecular level of rigid polymer molecules between flexible chains - the concept of molecular composites of Helminiak, Hwang e.a.(2, 4j. The other involves the use of polymer liquid crystals (PLCs). As discussed by Witt (5), compared to widely used engineering thermoplastics, PLCs show clear... 

Dow Chemical developed liquid crystalline polymers (LCP) based on diglycidyl ether of 4-4 -dihydroxy-o -methylstilbene in the 1980s (62,63). Liquid crystal thermoplastics and thermosets based on this novel chemistry showed excellent combinations of thermal, mechanical, and chemical properties, imachievable with traditional epoxies. However, commercialization of these products has not materialized. 

Knlichikhin VG, Plate NA (1991) Blend composites based on liquid crystal thermoplast. Rev Polym Sci USSR 33(l) l-37... 

Liquid crystal polymers (LCP) are a recent arrival on the plastics materials scene. They have outstanding dimensional stability, high strength, stiffness, toughness and chemical resistance all combined with ease of processing. LCPs are based on thermoplastic aromatic polyesters and they have a highly ordered structure even in the molten state. When these materials are subjected to stress the molecular chains slide over one another but the ordered structure is retained. It is the retention of the highly crystalline structure which imparts the exceptional properties to LCPs. 

Linear chain polymers with repeating sequences of hard and soft segments Possibility of formation of liquid crystal polymers and thermoplastic elastomers... 

DuPont Acetal EVA Nylon 6, 6/6, 6/12, Mineral Filled 6/6, Industrial PBT PET Polyethylene Modified Thermoplastic Elastomer Ionomer Liquid Crystal Polymer ... 

Report 3 Advanced Composites, D.K. Thomas, RAE, Famborough. Report 4 Liquid Crystal Polymers, M.K. Cox, ICI, Wilton. Report 5 CAD/CAM in the Polymer Industry, N.W. Sandland and M.J. Sebbom, Cambridge Applied Technology. Report 8 Engineering Thermoplastics, I.T. Barrie, Consultant. Report 11 Communications Apphcations of Polymers,... 

Thermoplastic polyesters, 20 31-95. See also Liquid-crystal polymers (LCPs) blow-molded bottles, 20 45-47 bottles for demanding contents, 20 52-53... 

The class of polyester-based liquid crystal polymers (LCPs) represent one of the most attractive materials in the field of engineering thermoplastics because of their superior mechanical properties, heat resistance, accuracy of dimensions, moldability and the excellent balance of these properties [1-5]. LCPs have been recently expanding their applications, in particular, those for precision electronic parts appropriate for surface mount technology (SMT). 

Connectors, switches, electric distributors, fuse boxes and other electric fittings need a subtle balance of electrical and mechanical properties, durability, cost and aesthetics. This broad field creates fierce competition not only between engineering thermoplastics and SMC/BMC for the main applications but also with polypropylene and polyethylene or PVC for the lower performance parts and, at the opposite end of the scale, with high-tech plastics such as polyetherketone, polyetherimide, liquid crystal polymers. .. For example, without claiming to be exhaustive ... 

Speciality thermoplastics polysulfone (PSU), PPS, fluoroplastics, PEEK, PEI, polyamide imide (PAI), liquid crystal polymers (LCP). 

Injection molded thermoplastic bipolar plates made of Vectra LCP (liquid crystal polymer) and Fortron PPS fabricated by Ticona Engineering Polymers, (http //www.ticona.com/redesign/ index/markets/innovation/fuel cell.htm Ticona Engineering Polymers. 2008 accessed March 2008.)... 

Some of the common types of plastics that are used are thermoplastics, such as poly(phenylene sulfide) (PPS) (see POLYMERS CONTAINING SULFUR), nylons, liquid crystal polymer (LCP), the polyesters (qv) such as polyesters that are 30% glass-fiber reinforced, and poly(ethylene terephthalate) (PET), and polyetherimide (PEI) and thermosets such as diallyl phthalate and phenolic resins (qv). Because of the wide variety of manufacturing processes and usage requirements, these materials are available in several variations which have a range of physical properties. 

Subclass All obtains the so-called self-reinforcing polymers viz. the polymeric liquid crystals (reinforcement by orientation in the mesophase followed by quenching below the solidification temperature). Subgroup A12 contains the thermoplastic elastomers, block copolymers in which the segments have very different Tg values, giving the possibility of intermolecular segregation and formation of physical networks. 

RPs that combine two different materials (plastic matrix and reinforcement) are a separate major and important segment in the plastic industry. They are also called plastic composites and composites. There are also self-reinforcing plastics such as liquid crystal polymers (Chapter 1) and others.301 It is a fact that RPs have not come near to realizing their great potential in a multitude of applications usually due to cost limitations that particularly involves the use of expensive fiber reinforcements (carbon, graphite, silica, etc.).1 Information on thermoplastic and thermoset plastic RPs are reviewed in Chapter 15. 

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