Thermoplastic copolyesters blends

The effect of °Co y-ray irradiation on the mechanical properties, surface morphology, and fractography of blends of plasticized PVC and thermoplastic copolyester elastomer, Hytrel (E.I. Du Pont de Nemours Company, Inc., Wilmington, Delaware), have been studied by Thomas et al. [445]. Radiation has two major effects on the blend cross-linking of the Hytrel phase and degradation of PVC phase. Both effects are found more prominent at higher radiation dose. 

Most TPEs fall in one of six categories, listed in order of increasing cost and performance styrenic block copolymers, polyolefin blends (TPOs), elastomeric alloys, thermoplastic polyurethanes (TPUs), thermoplastic copolyesters, and thermoplastic polyamides [3]. 

Bexloy V Thermoplastic copolyester elastomer blend E. I. du Pont de Nemours... 

In 1995, BASF announced the development of a biodegradable thermoplastic copolyester based on starch feedstock. A plasticizer reportedly is blended on-line with the copolyester to form a material which is antistatic, has good toughness, and good elongation at break. In 1999, BASF listed Ecoflex as the trade name for their biodegradable polyesters. ... 

Keyiuords Thermoplastic copolyester elastomers, polyfether ester)s, polyfester ester)s, morphology, mechanical properties, biodegradation, TPEE blends, TPEE recycling... 

Recent Developments in Thermoplastic Copolyester Elastomers Based Blends and Composites and Their Applications... 

Polymer blending represents important route for the development of new pol)nneric materials with improved physical and processing properties and optimal cost performance. Thermoplastic copolyester elastomers are generally used as modifiers, i.e. the minor phase... 

Whilst newer material types have emerged in recent years, primary TPE types can be categorized into two generic classes, block copolymers (styrenics, copolyesters, polyurethanes and polyamides) or thermoplastic/elastomer blends and alloys (thermoplastic polyolefins and thermoplastic vulcanisates). These TPE types are known as two-phase systems as essentially, a hard thermoplastic phase is coupled mechanically or chemically with a soft elastomer phase. The result is a TPE that has the combined properties of the two phases. 

A route to compatibility involving ionomers has been described recently by Eisenberg and coworkers [250-252]. The use of ionic interactions between different polymer chains to produce new materials has gained tremendous importance. Choudhury et al. [60] reported compatibilization of NR-polyolefin blends with the use of ionomers (S-EPDM). Blending with thermoplastics and elastomers could enhance the properties of MPR. The compatibility of copolyester TPE, TPU, flexible PVC, with MPR in aU proportions, enables one to blend any combination of these plastics with MPR to cost performance balance. Myrick has reported on the effect of blending MPR with various combinations and proportions of these plastics and provided a general guideline for property enhancement [253]. 

Most of the work to date concerns the area with the greatest potential for commercial exploitation, the blending of LCPs with conventional polymers. While a few studies of solution blending with Kevlar do exist [57-61], most of the work has centered on melt blending thermotropic copolyesters (Vectra, Xydar) with engineering thermoplastics (PET, PC, PEI, etc.). For convenience, this work may be separated into three blend regions based on LCP content, namely ... 

There are two classes of polyolefin blends elastomeric polyolefin blends also called polyolefin elastomers (POE) and nonelastomeric polyolefin blends. Elastomeric polyolefin blends are a subclass of thermoplastic elastomers (TPEs). In general, TPEs are rubbery materials that are processable as thermoplastics but exhibit properties similar to those of vulcanized rubbers at usage temperatures (19). In TPEs, the rubbery components may constitute the major phase. However, TPEs include many other base resins, which are not polyolefins, such as polyurethanes, copolyamides, copolyesters, styrenics, and so on. TPEs are now the third largest synthetic elastomer in total volume produced worldwide after styrene-butadiene rubber (SBR) and butadiene mbber (BR). 

A three layer pipe is obtained by coextrusion. The inner (or core layer) is made from CPVC/PVC blend, the outer layer is copolyester elastomer (which is not moisture resistant and thus requires protection by an outer sheath which is made from thermoplastic polyurethane. 

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). 

PBT is also blended with PMMA, PET/PC, and polybntadiene. Another development involving the use of PBT is coextrusion of PBT and copolyester thermoplastic elastomer. This can then be blow molded into under-hood automotive applications, which minimize noise vibration. PBT is suitable for applications requiring dimensional stability. It is particnlarly good in water, and it is also resistant to hydrocarbons oils without stress cracking. To improve PBT s poor notch impact strength, copolymerization with ethylene and vinyl acetate will improve toughness. 

Products that fulfil the requirements Products of 24 producers are certified by DIN CERTCO as compostable materials. Examples of pofymeric materials recognized and labelled as compostable include polylactic acid (e.g. Natiue Works PEA, Mitsui Lacea), thermoplastic starch (BIOTEC BIOPLAST), polycaprolacone (Solvay Caprolactones Solvay Interox CAPA), starch-based blends (Novamont Mater Bi), ahphatic-aromatic copolyesters (BASF Ecoflex, DuPont Biomax). 

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