Polymer styrene-acrylonitrile copolymers

Kambour, R. P. and Gruner, C. L., Effects of polar group incorporation on crazing of glassy polymers styrene-acrylonitrile copolymer and a bisphenol polycarbonate, J. Polym. Sci., Polym. Phys. Ed., 16, 703 (1978). 

Flame retardant (FR) PC/ABS blends constitute a very important class of thermoplastics because of their unique combination of properties provided by constituent polymers. Styrene acrylonitrile copolymer (SAN) matrix in ABS has a favorable interaction with PC allowing for a compatible blend to be commercially widely used without a compatibilizer [1]. These advantages make them an ideal choice for many computer and business equipment housings. They are also used to mold medical housings such as Automated External Defibrillators (AED), Blood... 

In addition to graft copolymer attached to the mbber particle surface, the formation of styrene—acrylonitrile copolymer occluded within the mbber particle may occur. The mechanism and extent of occluded polymer formation depends on the manufacturing process. The factors affecting occlusion formation in bulk (77) and emulsion processes (78) have been described. The use of block copolymers of styrene and butadiene in bulk systems can control particle size and give rise to unusual particle morphologies (eg, coil, rod, capsule, cellular) (77). 

Many cellular plastics that have not reached significant commercial use have been introduced or their manufacture described in Hterature. Examples of such polymers are chlorinated or chlorosulfonated polyethylene, a copolymer of vinyUdene fluoride and hexafluoropropylene, polyamides (4), polytetrafluoroethylene (5), styrene—acrylonitrile copolymers (6,7), polyimides (8), and ethylene—propylene copolymers (9). 

Other Polymers. Besides polycarbonates, poly(methyl methacrylate)s, cycfic polyolefins, and uv-curable cross-linked polymers, a host of other polymers have been examined for their suitabiUty as substrate materials for optical data storage, preferably compact disks, in the last years. These polymers have not gained commercial importance polystyrene (PS), poly(vinyl chloride) (PVC), cellulose acetobutyrate (CAB), bis(diallylpolycarbonate) (BDPC), poly(ethylene terephthalate) (PET), styrene—acrylonitrile copolymers (SAN), poly(vinyl acetate) (PVAC), and for substrates with high resistance to heat softening, polysulfones (PSU) and polyimides (PI). 

Acrylonitrile—Butadiene—Styrene. ABS is an important commercial polymer, with numerous apphcations. In the late 1950s, ABS was produced by emulsion grafting of styrene-acrylonitrile copolymers onto polybutadiene latex particles. This method continues to be the basis for a considerable volume of ABS manufacture. More recently, ABS has also been produced by continuous mass and mass-suspension processes (237). The various products may be mechanically blended for optimizing properties and cost. Brittle SAN, toughened by SAN-grafted ethylene—propylene and acrylate mbbets, is used in outdoor apphcations. Flame retardancy of ABS is improved by chlorinated PE and other flame-retarding additives (237). 

The valuable characteristics of polyblends, two-phase mixtures of polymers in different states of aggregation, were also discussed in the previous chapter. This technique has been widely used to improve the toughness of rigid amorphous polymers such as PVC, polystyrene, and styrene-acrylonitrile copolymers. 

To produce the Type 2 polymers, styrene and acrylonitrile are added to polybutadiene latex and the mixture warmed to about 50°C to allow absorption of the monomers. A water-soluble initiator such as potassium persulphate is then added to polymerise the styrene and acrylonitrile. The resultant materials will be a mixture of polybutadiene, polybutadiene grafted with acrylonitrile and styrene, and styrene-acrylonitrile copolymer. The presence of graft polymer is essential since straightforwsird mixtures of polybutadiene and styrene-acrylonitrile copolymers are weak. In addition to emulsion processes such as those described above, mass and mass/suspension processes are also of importance. 

Janarthanan et al. [67] have employed roughness on a micron scale to enhance the adhesion between two immiscible polymers, polycarbonate and styrene-acrylonitrile copolymer, SAN. Grooves of depths between 5 and 35 p,m were scribed in the polycarbonate surface before laminating the two polymers. The... 

The molecules join together to form a long chain-like molecule which may contain many thousands of ethylene units. Such a molecule is referred to as a polymer, in this case polyethylene, whilst in this context ethylene is referred to as a monomer. Styrene, propylene, vinyl chloride, vinyl acetate and methyl methacrylate are other examples of monomers which can polymerise in this way. Sometimes two monomers may be reacted together so that residues of both are to be found in the same chain. Such materials are known as copolymers and are exemplified by ethylene-vinyl acetate copolymers and styrene-acrylonitrile copolymers. 

In an example 70 parts (70 30 styrene acrylonitrile-copolymer) gets blended with 40 parts (35 65 acrylonitrile butadiene rubber). After it gets blended, the coagulation of the polymer is brought about by adding an acid or salt. 

However, a reactive styrene acrylonitrile copolymer (SAN)/gly-cidl methacrylate copolymer was found to be an effective reactive compatibilizer for the blends. Ethyltriphenyl phosphonium bromide was used as the catalyst. Probably, the epoxide groups react either with carboxyl or with hydroxyl groups of the PLLA end groups. This so modified polymer acts as the compatibilizer. Compatibilized PLLA/ABS blends exhibit an improved impact strength and an im-... 

Styrene acrylonitrile copolymer (SAN) copolymers have been commercially available since the 1940s. Due to their comparatively high price, initially they have been used in rather special applications. The history of styrenic polymers has been reviewed by various authors (1,2). 

P.G. Sanghvi, A.C. Patel, K.S. Gopalkrishnan, and S. Devi, Reactivity ratios and sequence distribution of styrene-acrylonitrile copolymers synthesized in microemulsion medium, Eur. Polym. /., 36(10) 2275-2283, October 2000. 

Core-shell emulsion polymers with a core or rubbery stage based on homopolymers or copolymers of butadiene are used as impact modifiers in matrix polymers, such as ABS, for styrene acrylonitrile copolymer methyl methacrylate (MMA) polymers, poly(vinyl chloride) (PVC), and in various engineering resins such as polycarbonate) (PC) poly(ester)s, or poly(styrene)s, further in thermosetting resins such as epoxies. 

M. Fowler, J. Barlow, and D. Paul, Effect of copolymer composition on the miscibility of blends of styrene-acrylonitrile copolymers with poly (methyl methacrylate), Polymer, 28(7) 1177-1184, June 1987. 

Glockner, G., van den Berg, J. H. M., Meijerink, N. L., Scholte, T. G. Characterization of copolymers chromatographic cross-fractionation analysis of styrene-acrylonitrile copolymers , in Kleintjens, L., Lemstra, P. (ed) Integration of Fundamental Polymer Science and Technology , Elsevier Applied Science Publ., Barking, UK (1986), p. 85... 

Sonic Modulus. If crack or craze branching is the operative mech-nism in toughening, toughness should be directly related to the difference in sonic speeds in matrix and dispersed phases. Experiments to confirm this effect were undertaken using three commercial ABS resins. These were selected to represent the three main rubber types encountered commercially an acrylonitrile/butadiene copolymer rubber, a butadiene rubber with grafted styrene/acrylonitrile copolymer, and a block polymer of... 

Acrylonitrile-Butadiene-Styrene (ABS) Copolymers. This basic three-monomer system can be tailored to yield resins with a variety of properties. Acrylonitrile contributes heat resistance, high strength, and chemical resistance. Butadiene contributes impact strength, toughness, and retention of low-temperature properties. Styrene contributes gloss, processibility, and rigidity. ABS polymers are composed of discrete polybutadiene particles grafted with the styrene-acrylonitrile copolymer these are dispersed in the continuous matrix of the copolymer. 

Figure 12.8 Microcolumn size exclusion chromatogram of a styrene-acrylonitrile copolymer sample fractions transferred to the pyrolysis system are indicated 1-6. Conditions fused-silica column (50 cm X 250 xm i.d.) packed with Zorbax PSM-1000 (7 j.m dty, eluent, THF flow rate, 2.0 xL/min detector, Jasco Uvidec V at 220 nm injection size, 20 nL. Reprinted from Analytical Chemistry, 61, H. J. Cortes et al., Multidimensional chromatography using on-line microcolumn liquid chromatography and pyrolysis gas chromatography for polymer characterization , pp. 961 -965, copyright 1989, with permission from the American Chemical Society.

Chiou JS, Paul DR (1987) Gas permeation in miscible homopolymer copolymer blends. l.Poly(methyl methacrylate) and styrene acrylonitrile copolymers. J Appl Polym Sci 34 1037-1056... 

The styrene-acrylonitrile copolymers were prepared in the form of a thin film. The graft polybutadiene solution was coated on a glass slide. But, for the graft polymer containing acrylonitrile, it was undesirable to use the glass slide because of the induced orientation, therefore, we used a Mylar film to support a thick smooth film of the graft rubber. 

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