Thermoplastic copolyesters crystallinity

Thermoplastic copolyesters are condensation block copolymers based on a crystalline polyester hard segment and an amorphous long-chain polyether soft s ment. The hard segment, for example, formed... 

Various liquid crystalline copolyesters (LCP s) were used depending on the particular thermoplastic matrix which was selected. In this work three high performance matrices were used polyether-... 

S. Saikrasun, S. Bualek-Limcharoen, S. Kohjiya, and K. Urayama. Thermotropic liquid-crystalline copolyester/thermoplastic elastomer in situ composites. I. Rheology, morphology, and mechanical properties of extruded strands. J. Appl. Polym. ScL, 89 2676-2685, 2003. 

S. Saikrasun and T. Amomsakchai. Phase behavior and properties of in situ-reinforcing elastomer composites based on thermoplastic elastomers and thermotropic liquid crystalline copolyester. J. Appl. Polym. ScL, 101 1610-1619, 2006. 

Formation of random copolyesters resxilts in many physical changes in the PHAs, including liquid-crystalline-amorphous forms, and a variety of piezoelectric, thermoplastic, elastomeric and other properties. ... 

Saikrasun S, Bualek-Limcharoen S, Kohjiya S, Urayama K. Thermotropic liquid-crystalline copolyester (Rodrun LC3000)/thermoplastic elastomer (SEBS) in situ composites II. Mechanical properties and morphology of... 

The underlying morphology will have a large effect on the physical properties. The soft phase is usually the continuous phase to maintain the elastomeric behavior of the material. In materials that have crystalline hard segments, such as copolyesters and polyurethanes, both phases are essentially continuous. Thermoplastic elastomers almost never have the soft segment as the isolated phase and the hard segment as the continuous phase. The most... 

Skin/core morphologies are common in blends of LCP s and thermoplastic polymers and they play a significant role in defining the properties of both extruded and injection molded samples. Usually, LCP s in the skin have a higher degree of orientation than in the core when the blends are extruded or injection molded (Husman et al. 1980 Hedmark et al. 1989 Lee 1988). Baird et al. (Baird and Mehta 1989 Baird and Sukhadia 1993) observed a skin/core morphology in blends of PA 66 with HBA/HNA and 40 PET/60 PHB and 20 PET/80 HBA copolyesters. More LCP fibers were present in the skin than in the core for both systems. Isayev and Swaninathan (1994) also reported shell-core structure in the fracture surfaces of injection molded blends of HNA/HBA liquid crystalline copolyesters and poly (etherimide). 

Liquid crystalline polymers such as thermoplastic elastomer copolyesters are being used in lower power, higher speed gears because it allows them to tolerate inaccuracies and reduce noise while providing sufficient dimensional stability and stiffness [7]. 

Commercial aliphatic polyesters and copolyesters under the tradename Bionolle (Showa Highpolymer, Japan) are white crystalline thermoplastics, have melting points ranging from... 

Ce, the range of Tg is from about lO C to -40 C. The latter is typical of an elastomer and, indeed, when the sidechain is in the range of Ca to Ce, the materials are truly thermal elastomers with greatly decreased crystallinity compared to PHB and the PHB/V copolyesters which are the thermoplastics. lo, ii... 

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