Xydar, aromatic polyesters

The first LCP to be launched commercially was Dartco s Xydar, introduced in 1984 [11]. Xydar injectionmolding resins are aromatic polyesters based on terephthalic acid, p-hydroxybenzoic acid, and p,p -dihydroxybiphenyl. Xydar has a high melting point (close to 400°C), which necessitates certain modifications to processing equipment. It also has a high melt viscosity making it difficult to mold in... [Pg.559]

Aromatic polyester Xydar Dartco 250 42-47 v-0 Injection grade... [Pg.405]

This search has recently been successful in the first commercial liquid crystal aromatic polyester. This is the copolymer of terephthahc acid, p-hydroxybenzoic acid and 4,4 -biphenol (Xydar), and is fabricated at 430 °C. It has an HDT of 355 °C and a high impact strength across the large temperature range — 50 °C to 240 °C. [Pg.57]

In late 1985 Hoechst Celanese commercialized a family of LCPs under the trademark Vectra. Based on hydroxybenzoic acid and naphthalene derivatives, like Xydar , Vectra LCP exhibits a nematic structure. Although Xydar and Vectra are classified genetically as wholly aromatic polyesters with similar basic structures, it is important to note that many of the characteristics of the LCP polymer systems vary significantly with their chemical compositions. Other companies that are commercially active include Sumitomo Chemical, Mitsubishi Chemical, Ueto and Unitika. [Pg.259]

Liquid crystal polymer Aromatic polyester LCP Xydar, Zenite, Vectra... [Pg.134]

Liquid crystalline aromatic polyamides were the first chemical class to be commercialised. The best known example is Kevlar fibre which is spun from liquid crystalline solution to obtain the benefit of the high orientation present in the nematic phase. Subsequently, melt-processable main-chain polyesters were developed and brought to the market (Amoco with Xydar, Hoechst-Celanese with Vectra). [Pg.199]

Wholly para substituted polyesters are normally infusible, unless disruptive groups are substituted onto the aromatic rings, e.g. methyl or chlorine. Commercially, it has proved more attractive to use symmetrical monomers which are able to disrupt crystallinity because they are significantly different in size. Sequences therefore match at infrequent intervals along the chain. Xydar is an example of a commercial LCP using this principle. [Pg.200]

Xydar Amoco Performance Products Inc. s tradename for its family of liquid-crystal polymers, xylene A colorless aromatic hydrocarbon liquid. It is used as a solvent, in the manufacture of polyester plastics, and as a chemical intermediate. [Pg.578]

Most LC polymers in the market are linear, highly aromatic thermotropic polyesters. They combine chemical stability with chain rigidity and retain dimensional stability (remain as glasses) up to 200°C or 300°C and are also very chemically stable (resistant to oxidation). These types of PLCs, such as the commercial Vectra and Xydar, are usually processed in the melt state with conventional fabrication techniques such as extrusion and molding (see Chapter 14). A major advantage of such polymers is that they can be melt processed and form extranely precise molded structures that do not shrink on cooling. They have been used in molded parts for microelectronics and in mounting brackets for optical communications. [Pg.95]

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