Terpolymer blends styrene/maleic anhydride

Compatibilization improves the morphological stability of polymer blends when block or graft copolymers are used by the introduction of steric hindrance to drop coalescence. A chemical approach is possible for formation of grafted PC with SAN chains at the PC/SAN interface. SAN-amine copolymer is prepared by reaction of a terpolymer of styrene, maleic anhydride, and acrylonitrile with l-(2aminoethyl) piperazine. The SAN-amine polymer is miscible with the SAN matrix of ABS and reacts with PC. The formation of graft polymer has resulted in the reduction of SAN dispersed-phase particle size. The blend morphology has been found to stabilize in the mixing process. 

Nevertheless, a terpolymer of styrene-maleic anhydride and acrylonitrile (S/MA/AN) met the specifications of superior thermal properties but it was difficult to injection mold using the plunger-type presses available in the early 1940 s. This objection was overcome by blending with NBR, SBR, or HIPS. 

Polycarbonate is blended with a number of polymers including PET, PBT, acrylonitrile-butadiene-styrene terpolymer (ABS) rubber, and styrene-maleic anhydride (SMA) copolymer. The blends have lower costs compared to polycarbonate and, in addition, show some property improvement. PET and PBT impart better chemical resistance and processability, ABS imparts improved processability, and SMA imparts better retention of properties on aging at high temperature. Poly(phenylene oxide) blended with high-impact polystyrene (HIPS) (polybutadiene-gra/f-polystyrene) has improved toughness and processability. The impact strength of polyamides is improved by blending with an ethylene copolymer or ABS rubber. 

Seymour, R. B., Styrene-Maleic Anhydride-Vinyl Monomer Terpolymers and Blends , in High Performance Polymers Their Origin and Development, ed. Seymour, R. B. and Kirshenbaum, G. S., Elsevier, New York, p. 125 (1986). 

Hall W, Kruse R, Mendelson R and Trementozzi Q (1983) New styrene-maleic anhydride terpolymer blends. ACS Symp Ser 229 49-64. 

A group of new, fully miscible, polymer blends consisting of various styrene-maleic anhydride terpolymers blended with styrene-acrylonitrile copolymer and rubber-modified versions of these materials have been prepared and investigated. In particular the effects of chemical composition of the components on heat resistance and the miscibility behavior of the blends have been elucidated. Toughness and response to elevated temperature air aging are also examined. Appropriate combinations of the components may be melt blended to provide an enhanced balance of heat resistance, chemical resistance, and toughness. 

HALL ET AL. Styrene-Maleic Anhydride Terpolymer Blends... 

Styrene-Maleic Anhydride (SMA) Copolymer and Terpolymer Based Blends... 

Specifically, PVC blends with polyethylene, polypropylene, or polystyrene could offer significant potential. PVC offers rigidity combined with flammability resistance. In essence, PVC offers the promise to be the lowest cost method to flame retard these polymers. The processing temperatures for the polyolefins and polystyrene are within the critical range for PVC. In fact, addition of the polyolefins to PVC should enhance its ability to be extruded and injected molded. PVC has been utilized in blends with functional styrenics (ABS and styrene-maleic anhydride co-and terpolymers) as well as PMMA offering the key advantage of improved flame resistance. Reactive extrusion concepts applied to PVC blends with polyolefins and polystyrene appear to be a facile method for compatibilization should the proper chemical modifications be found. He et al. [1997] noted the use of solid-state chlorinated polyethylene as a compatibilizer for PVC/LLDPE blends with a significant improvement in mechanical properties. A recent treatise [Datta and Lohse,... 

Papazoglou and Rosenthal[71] produced nylon blends having improved low-temperature properties. Moldable nylon-6 blends with improved low-temperature impact strength and reduced brittleness were prepared by melt blending nylon-6, maleic anhydride-g-ethylene-propylene-diene terpolymer, and rubber modified styrene-maleic anhydride copolymer. The impact property of the rubber-modified nylon composition is given in Table 5. The blend components were melt blended at temperatures between 260 and 310 °C. As a standard, all three components of the blend were simultaneously melt blended (A). Nylon-6 was melted first and then the functionalized terpolymer was melt blended prior to downstream introduction of the rubber modified copolymer (B). Nylon-6 and the functionalized terpolymer were first melt blended and then the rubber modified copolymer was added to the melted mixture at a downstream feed port (C). 

STYRENE-MALEIC ANHYDRIDE-VINYL MONOMER TERPOLYMERS AND BLENDS... 

Blends of copolymers of styrene and acrylonitrile and butadiene and acrylonitrile called ABS plastics which are more ductile than polystyrene, are now used at an annual rate of almost 500 thousand tons. Terpoljrmers of styrene, acrylonitrile and maleic anhydride (Cadon) have heat deflection points above lOOOC.Q)While the physical properties of both ABS and the maleic anhydride terpolymers are superior to polystyrene, the improvements are not sufficient to classify them as high performance plastics. 

A Monsanto patent by Lavengood [38] reported on the free radical copolymerization of styrene (S), acrylonitrile (AN) and maleic anhydride (MA) and the use of these terpolymers in the reactive compatibilization of PA6/ABS blends. Indeed, the amine end groups of nylon react with the MA groups of the terpolymer with formation of a graft copolymer at the interface. 

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