Polyester/polycarbonate blends

Polycarbonate—polyester blends were introduced in 1980, and have steadily increased sales to a volume of about 70,000 t. This blend, which is used on exterior parts for the automotive industry, accounting for 85% of the volume, combines the toughness and impact strength of polycarbonate with the crystallinity and inherent solvent resistance of PBT, PET, and other polyesters. Although not quite miscible, polycarbonate and PBT form a fine-grained blend, which upon analysis shows the glass-transition temperature of the polycarbonate and the melting point of the polyester. 

Polycarbonate-ABS blends, 19 824-825 Polycarbonate blends, 20 361-362 Polycarbonate-polyester blends, 19 824, 825 Polycarbonate resin(s)... 

Polycarbonate-polyester blends are used on extenor parts for the automotive industry. Such blends combine the toughness and impact strength of polycarbonate with die crystallinity and inherent solvent resistance of PBT, PET. and other polyesters. 

Polycarbonate / Polyester Blends. Contour maps of the temperature-frequency variation of complex relative permittivity have been obtained for impact-modified PC/PBT and PC/PET blends [3,43] and for their constituent polycarbonate [3], PBT [44] and PET [45] homopolymers. In the impact-modified PC/PBT blend (Figure 7), as in each of the blends, a single broad p-absorption is observed but the separate a-absorptions of the constituents persist. 

Simultaneously to those developments the technology of polycarbonate-polyester blends has been extensively studied by various laboratories, confirming the early technical developments and further contributing to polymer science in this field ... 

Stapron E. Information package concerning a polycarbonate-polyester blend grade family. 

Usage of phosphoms-based flame retardants for 1994 in the United States has been projected to be 150 million (168). The largest volume use maybe in plasticized vinyl. Other use areas for phosphoms flame retardants are flexible urethane foams, polyester resins and other thermoset resins, adhesives, textiles, polycarbonate—ABS blends, and some other thermoplastics. Development efforts are well advanced to find appHcations for phosphoms flame retardants, especially ammonium polyphosphate combinations, in polyolefins, and red phosphoms in nylons. Interest is strong in finding phosphoms-based alternatives to those halogen-containing systems which have encountered environmental opposition, especially in Europe. 

Blends with good mechanical properties can be made from DMPPO and polymers with which DMPPO is incompatible if an appropriate additive, compatibilizing agent, or treatment is used to increase the dispersion of the two phases. Such blends include mixtures of DMPPO with nylon, polycarbonate, polyester, ABS, and poly(phenylene sulfide). 

We previously reported that brominated aromatic phosphate esters are highly effective flame retardants for polymers containing oxygen such as polycarbonates and polyesters (9). Data were reported for use of this phosphate ester in polycarbonates, polyesters and blends. In some polymer systems, antimony oxide or sodium antimonate could be deleted. This paper is a continuation of that work and expands into polycarbonate alloys with polybutylene terephthalate (PBT), polyethylene terephthalate (PET) and acrylonitrile-butadiene-styrene (ABS). 

Figure 3. Flame Retarding Polycarbonate/PBT Polyester Blends (12% Flame Retardant)...

High-impact polystyrene (HIPS) is produced by polymerizing styrene in the presence of a rubber, usually poly(l,3-butadiene). HIPS has improved impact resistance compared to polystyrene and competes with ABS products at low-cost end applications such as fast-food cups, lids, takeout containers, toys, kitchen appliances, and personal-care product containers. HIPS as well as ABS and SMA are used in physical blends with other polymers, such as polycarbonates, polyesters, and polyamides, to improve impact resistance (Sec. 2-13c-3). 

Polybutylene therephthalate (PBT) has been used as a blend component to provide chemical resistance in various systems, but the most interesting one results from a combination with polycarbonate and, eventually, an Impact modifier of the coreshell type. Polyester blends containing polycarbonate exhibit ester interchange chemical reactions, which add to the complexity of property control of these materials. DEVAUX and co-workers (14) have examined the transesterification reaction catalysed by residual catalysts in PBT which can lead to the formation of block and random copolymers. They have shown that allyl or aryl phosphites inactivate the residual titanium catalyst and minimise the transesterification reaction. HOBBS et al. (15) reported a way of controlling miscibility behaviour, morphology and deformation mechanisms, in order to obtain blends compati-bilisation and excellent mechanical properties. 

Brief reviews covering redistribution reactions in polyester and in polycarbonate binary blends have been prepared by Porter et al. [1989] and Porter and Wang [1992]. Selected references for redistribution processes in PEST/PEST blends are listed in Table 5.7. Early studies of these processes focused on measuring the extent of redistribution under specific processing conditions rather than on producing compatibilized polymer blends with an attractive balance of properties. A number of more recent studies have reported the limits of miscibility for certain melt-mixed polyester pairs in the absence of transesterification — see for example the NMR study of PC/PET blends [Abis et al., 1994]. 

S-MMAIPC blend. This blend (Novacor SD-9101) was reported to have better flow, surface finish and scratch resistance than PC/polyester blends and an equivalent level of impact toughness (Table 15.24). It is believed that these formulations also include some acrylic rubber (core-shell type) for impact modification. One would expect a sufficient level of partial miscibility for self-compatibilization between the styrene-methyl methacrylate copolymer (S-MMA) and the polycarbonate especially at high MMA content of the copolymer, since the binary blends of PMMA... 

Blends of condensation polymers containing functional groups internally or at chain ends (such as polycarbonates, polyesters, polyamides, and the like) may undergo intermolecular exchange reactions when mixed in the molten... 

Miller et al. (36) studied the MW distribution of polycarbonates and aromatic polyesters blends using two solvents selectively. A blend of methylene chloride/HFIP (70 30) dissolves both polymers, but THF dissolves only polycarbonate. Separations were performed on a column set comprising a PL gel 5 pm mixed bed, a 100 A column, and a 5 pm precolumn. Although these two polymers coeluted, use of a diode array UV detector set at 285 nm allowed detection of the polyester because absorption is 20 times greater for PET versus polycarbonate. 

Examples of polyester blends not shown in earher sections are listed in alphabetical order of the second polymer in the blend unless otherwise noted. Polycarbonate blends are also included as polyesters. When copolymer characterization was not performed, the structure of the compatibilizing copolymer is inferred from the... 

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