PC/polyester blends

In one example, over 150 parts of a steel riding mower have been incorporated into two injection molded thermoplastic panels made from a PC/polyester blend. These are adhesively bonded to a lower fiber reinforced PU lower member. Although the plastic material cost is ten times that of the sheet metal it replaces, economies in assembly, painting and part inventory give the final product a 10% lower cost. 

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... 

PC/polyester blends are resistant to hydrocarbons, alcohols, organic acids, inorganic aqueous salts and mild acid or base solutions. PC/polyester blends present superior chemical resistance over polycarbonate. This makes PC/polyester blends suitable for utilizations requiring resistance to intermittent contact with fuels or oils. 

Figure 12.16 Exchange ReacHons Which Can Occur in the Melt Mixing of PC/ Polyester Blend. Where X=2 PET and X=4 PBT. (Continued)...

SAME TYPE BLENDS, TRADE NAME AND MANUFACTURER In the United States PC/polyester blends are produced under the trademark SABRE engineering resins by The Dow Chemical Company (2040 Dow Center, Midland, Michigan 48674) under the trademark Makroblend by Miles Inc. under the trademark Ektar by Eastman Chemical Company and under the trademark Xenoy by the General Electric Company. 

Several combinations of PC/polyester blends have been commercial for over two decades. One of the initial blends was PC/PBT, introduced by General Electric under the tradename Xenoy [59]. This blend is phase separated as commercially employed and relies on the crystallinity of PBT to yield chemical and environmental stress crack resistance to PC. With time/temperature exposure, ester exchange reactions will lead to miscibility. For this blend, as commercially utilized, miscibility is not desired because the crystallization of PBT will be reduced or eliminated. Thus, for commercial use stabilizers (such as phosphites and diphosphites) are added to neutralize the ester-exchange polymerization catalysts present in commercial PBT [60,61]. This blend has good mechanical compatibility and toughness. The high heat distortion temperature of PC is retained. This blend is utilized in automotive applications, such as automotive body panels, lawn mowers, connectors, appliances, tool housings, and cellular phones. PC/PET blends were commercialized shortly after PC/PBT blends and one... 

Blendex . [GE Specialty] ABS and blends modifier resin for PVC, qp-oxies, polyurethane, PC, polyesters. 

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]. 

Table 5.7 omits references in which transesterification in PEST/PEST blends is brought about under static conditions either by annealing or heating in a DSC chamber. Blends in such examples were prepared by solution precipitation. Selected recent references in this class include PC + polyester urethane [Ahn et al., 1997] PBT + PET [Backson et al., 1995] Polyarylate + PBT [Denchev et al., 1996] PCL + PBT-CL copo-... 

PPE/PBT (Dialov X. BE. Gemax . lupi-ace ) Polyesters such as PBT or PET offer to PPE blends similar advantages as PA (chemical resistance because of semi-crystalline nature) but with lower moismre sensitivity. Commercial compatibilized PPE/polyester blends normally contain an elastomer and PC for improved shear stability. The blends show excellent processability, high solvent and temperature resistance as well as dimensional stabUify. 

The most important polyester blends are those with PC. The presence of PC in PET/PC increases the crystallization rate of PET and allows faster cycles. These materials are discussed below, under the heading of PC/PET blends. 

PC/PET and PC/PBT blends combine PC toughness with the chemical resistance of polyester to offer a desirable combination of high strength, toughness (including at low temperature), chemical resistance and excellent UV stability along with improved flame retardancy and colorability. 

Modification of Engineering Resins Specific interaction of the phosphonium ionomer from Exxpro elastomer with selected engineering resins such as Polycarbonates(PC), Polyesters(PET), Polyacrylates(PAE), Polyamides(PA), Polyphenylene Oxide(PPO), and Acetals(PAc) can be utilized to compatibilize, impact modify or nucleate the above resin in blends with similar polymers. Typical examples are ... 

Spedalty plastics snch as PC, acrylonitrile-butadiene-styrene (ABS), PU, polyamides (PA), thermoplastic elastomers, polysnlfone and polyetheretherketone (PEEK) are being used in a nnmber of special applications in medical devices, whenever high performance is required. There are also a number of polymer blends used in this category (i.e., PC/ABS and PC/polyester), if property envelopes are required to be further improved. 

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. 

The persistence of the glass transition temperatures of the component polymers in each of the blends, and the lack of a third Tg peak at an intermediate temperature (see, for example. Figure 8), confirms that the blends contain two phases. The temperature shift in each Tg is a consequence of the partial miscibility of the component polymers in the melt. The very slight increase in the Tg of PBT and PET in the PC/PBT and PC/PET blends respectively indicates that the polyester-rich phase contains only a small amount of polycarbonate, whereas the significant decrease in Tg in the PC component of the blends suggests the presence of substantial proportions of PBT or PET respectively in the phase consisting predominantly of polycarbonate. 

For impact-modified PC/PBT and PC/PET blends evidence has been presented for partial miscibility of the component polymers and for a two-phase blend morphology with a polyester-rich dispersed phase in a continuous matrix rich in polycarbonate. Other absorptions are attributed respectively to MWS interfacial polarization, to the presence of the impact modifier and to a phosphite processing stabilizer. 

Synonyms Brominated triaryl phosphate Empirical Ci8H9Bre04P Properties M.p. HOC Uses Flame retardant for thermoplastic polyesters, PC, ABS, blends Tris-dibromopropylisocyanurate CAS 52434-90-9 Empirical Ci2Hi5Br6N303 Properties M.p. 106-108 C Uses Flame retardant Manuf./Distrib. Akzo Nobel bv http //www. akzonobel. com http //www.functionalchemicals.com] Teijin Chems. 

Fyrolflex RDP is a resorcinol bis(diphenyl phosphate). It is a liquid that is designed for use in engineering plastics such as polyesters, modified PPO as well as PC/ABS blends and HIPS. It has low volatility and good thermal stability, meaning it can outperform triaryl phosphates, such as triphenyl phosphate. Fyrolflex RDP is used either as a flame retardant or, in low doses, as a flow modifier. 

The PC/Polyester product line and its technology are however not limited to those PC/P3T blends, but also includes impact modified amorphous PC/PET nonmiscible blends as indicated by the DMS scan (fig 3a) with two sharp glass transitions at 81 for PET and slightly broadened damping characteristics of polycarbonate at 148 C. 

Polycarbonate (PC) and polyesters blends are phase separated and are obtained without ester exchange reaction. So, the crystallinity of polyester is maintained. These blends combine the characteristics of both polymers. Catalysts could be added to promote ester exchange reaction and yielding to the disappearance of the PET crystallinity. 

This chapter reviews the research and the most relevant progresses in polycarbonates (PC)s science and provides a comprehensive source of information on history, synthesis, processing and applications. The application of different polymerization procedure of the commercial aromatic bisphenol-A polycarbonate (referred herein as PC) and the innovative enzymatic catalysed polymerization of aliphatic polycarbonate are summarized. Due to the high engineering performance of PC polymer, an extensive section on mechanical, electrical, chemical and thermal properties is included. The thermo and photo oxidative behaviours, the hydrolytic stability and the consequent modification on PC chemical structure are also discussed. The development of PC polymeric materials such as composites and blends are also addressed, emphasizing in particular the properties and the applications of impact modified PC blends and even of the PC/Polyester systems. 

Therefore on the base of data above reported, the melt mixing of either the PC/polyester and PC/Ny6 blends can be considered a suitable method for plastics recycling resolving the growing environmental problem due to increased amount of waste produced by society. These method could constitute also a powerfully route to synthesize new polymeric materials. 

Polycarbonate, PC. PC was introduced in 1958. To improve its processability, impact behavior, and solvent resistance, PC must be modified. The first blends with polyolefins, PO, or with ABS were developed in 1960. These were rapidly followed by alloys with polysiloxanes in 1961, PAES in 1965, PET in 1966, POM in 1968, PSF -n ABS in 1969, PES -n ABS in 1970, PBT in 1971, PA or PPE + SBR in 1973, PPS in 1974, PS in 1976, styrene-maleimide (SMI) in 1977, polyaramid (PARA) in 1979, etc. Owing to the chemical nature of the statistical segment, PC can be readily compatibilized or modified, becoming a frequent component of polymer blends. Its affinity to acrylates has been widely explored. However, only in 1986 was its miscibility with polymethylmethacrylate, PMMA, disclosed [Kambour, 1986]. These blends were found to be suitable for glazing materials and optical disks. Another miscible blend of PC (with aliphatic polyester of neopentyl glycol) was discovered in 1991 [Lundy et al., 1991]. Commercial PC/PA blends are relatively recent. In 1992 Toray Industries introduced Toray-PC and Rohm Haas Paraloid. Both blends contain about 30 % of PARA and PA, respectively. 

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