Polymer high temperature specialty

PNC have been prepared with virtually all polymers, from water-soluble macromolecules to polyolefins and high-temperature specialty resins such as polyimide (PI). Elastomer-based PNCs with large clay platelets have been commercialized for improved barrier properties in automotive tires or sport balls. Elastomeric epoxy resins with clays demonstrate substantial improvement in mechanical properties (e.g., tensile modulus and strength) [Varghese and Karger-Kocsis, 2005 Utracki, 2008]. In this chapter we focus primarily on clay-containing PNCs, the CPNCs. 

Most polyesters (qv) are based on phthalates. They are referred to as aromatic-aHphatic or aromatic according to the copolymerized diol. Thus poly(ethylene terephthalate) [25038-59-9] (PET), poly(butyelene terephthalate) [24968-12-5] (PBT), and related polymers are termed aromatic-aHphatic polyester resins, whereas poly(bisphenol A phthalate)s are called aromatic polyester resins or polyarylates PET and PBT resins are the largest volume aromatic-aHphatic products. Other aromatic-aHphatic polyesters (65) include Eastman Kodak s Kodar resin, which is a PET resin modified with isophthalate and dimethylolcyclohexane. Polyarylate resins are lower volume specialty resins for high temperature (HDT) end uses (see HeaT-RESISTANT POLYAffiRS). 

PolyQ>phenylene sulfide) (PPS) deserves much attention as an engineering and a conductive plastic and in some cases as a specialty polymer with excellent performance. Lenz first reported that PPS is synthesized by the polycondensation of / -halothiophenolate alkali-metal salts at high temperature [83], Commercially PPS is produced by the polycondensation of -dichlorobenzene and sodium sulfide in A-methyl-2-pyrrolidone [84]. These polymerizations proceed only at high temperature and pressure, and it is difficult to remove the metal halides such as sodium chloride as by-products in order to obtain pure PPS salt contamination degrades the electric performance and moldability. 

It is believed that difurfural has the potential of a great future as a building block for high-temperature polymers. Specialty polymer manufacturers are in the process of evaluating difurfural for such applications. 

Catalysis has also had a major impact on the functional and specialty chemicals businesses, providing lower cost routes and higher performance materials than would have otherwise been possible. Major examples are from polymer syntheses including Ziegler-Natta, anionic, cationic polymerization processes, for formation of polyolefins, ABS resins, polyesters and other synthetic materials. Future materials areas include high temperature composites, electronic materials and conducting organics. 

Specific blends, which could offer an interesting combination of properties with proper com-patibilization, include PPS/PSE, PEl/PPS, PA/PSE, PA/PEI, and PC/PPS. Patent activity has been noted for most of these blend combinations as well as other selected blends involving engineering polymers as noted in Table 17.3. A number of recent patent and published papers have discussed blends of engineering polymers with various specialty polymers including high temperature polymers, liquid crystalline polymers (LCP s), conductive polymers, and as matrix materials for molecular composites. These will be discussed in the following sections. 

The last several decades have seen an exponential increase in the activity of engineering polymer blends. While this activity will continue, the area that will probably show the most future increase in commercial activity will be in high temperature systems. These blends include LCP and molecular composites as subsections that will be discussed separately. The activity in high temperature polymer blends has been primarily in the patent and published literature. Several examples of developmental and specialty commercial blends have emerged and many more are expected to follow in the future. 

In addition to these more obvious derivatives, many specialty aromatics are available in such high proportion as to change the economics of the polymers based on them. A notable example is durene (l,2,4, -> tetramethylbenzene), a starting material for p omel-litic dianhydride, which is reacted with diamines to give the high-temperature-resistant polyimides. 

The blend comprised at least two sulfone polymers, e.g., PES and PSF, and at least one non-sulfone polymer (e.g., PS, PPE, PEI, PC, PA, PEST, PP, or PE). The nucleating agent was either talc, mica, silica, Zn-stearate, Al-stearate, Ti02, or ZnO. The foams were used as insulation for high temperature structural applications. Since in the preceding part PPS blends with PSF were described, in Table 1.71 examples of PSF blends with other specialty resins are listed. 

After introducing incorporation costs, the cost of the composite may be higher or lower than that of the unfilled polymer. For low-cost commodity plastics, the term filler (implying cost reduction) may be a misnomer since manufacturing costs may offset the lower cost of most mineral fillers. For higher cost specialty high-temperature thermoplastics, the final cost of, for example, glass fiber-reinforced polyetherimide is usually less than that of the unmodified polymer. 

Matrax, Thermoplastic olefinic elastomers, M.A. Industries Inc., Polymer Div. Matrimid, High-temperature matrix resins, Ciba Specialty Chemicals, Performance Polymers MatVantage SMC, Needled mat for SMC, PPG Industries, Inc., Fiber Glass Maxi-Clean, Granulated melamine mold cleaning media, Maxi-Blast, Inc. 

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