Copolymerization styrene-acrylonitrile

The question of chain entanglements has been studied more extensively in acrylonitrile-styrene copolymerization (17) (Table IV). At the first appearance of popcom particles in this system, the copolymer has a 1 1 molar ratio of acrylonitrile to styrene units. Its mean chain length is 20,000. 

Polymerization and Spinning Solvent. Dimethyl sulfoxide is used as a solvent for the polymerization of acrylonitrile and other vinyl monomers, eg, methyl methacrylate and styrene (82,83). The low incidence of transfer from the growing chain to DMSO leads to high molecular weights. Copolymerization reactions of acrylonitrile with other vinyl monomers are also mn in DMSO. Monomer mixtures of acrylonitrile, styrene, vinyUdene chloride, methallylsulfonic acid, styrenesulfonic acid, etc, are polymerized in DMSO—water (84). In some cases, the fibers are spun from the reaction solutions into DMSO—water baths. 

Radical copolymerization is used in the manufacturing of random copolymers of acrylamide with vinyl monomers. Anionic copolymers are obtained by copolymerization of acrylamide with acrylic, methacrylic, maleic, fu-maric, styrenesulfonic, 2-acrylamide-2-methylpro-panesulfonic acids and its salts, etc., as well as by hydrolysis and sulfomethylation of polyacrylamide Cationic copolymers are obtained by copolymerization of acrylamide with jV-dialkylaminoalkyl acrylates and methacrylates, l,2-dimethyl-5-vinylpyridinum sulfate, etc. or by postreactions of polyacrylamide (the Mannich reaction and Hofmann degradation). Nonionic copolymers are obtained by copolymerization of acrylamide with acrylates, methacrylates, styrene derivatives, acrylonitrile, etc. Copolymerization methods are the same as the polymerization of acrylamide. 

Uses Copolymerized with methyl acrylate, methyl methacrylate, vinyl acetate, vinyl chloride, or 1,1-dichloroethylene to produce acrylic and modacrylic fibers and high-strength fibers ABS (acrylonitrile-butadiene-styrene) and acrylonitrile-styrene copolymers nitrile rubber cyano-ethylation of cotton synthetic soil block (acrylonitrile polymerized in wood pulp) manufacture of adhesives organic synthesis grain fumigant pesticide monomer for a semi-conductive polymer that can be used similar to inorganic oxide catalysts in dehydrogenation of tert-butyl alcohol to isobutylene and water pharmaceuticals antioxidants dyes and surfactants. 

In a typical ABS mass polymerization process, styrene and acrylonitrile are copolymerized in the presence of a diene-based rubber. Initially, the rubber is dissolved in the monomers and a continuous homogeneous phase prevails. 

These early works have been reviewed by Fioshin (4) and well summarized by Bbeitenbach (5). Besides, Breitenbach has made a study of the polymerization mechanism using the copolymerization method and has shown that the reaction mechanism depends on the ions used in the electrolytic discharge and on the monomer present in the system. Cationic processes were also found to be initiated in a nitrobenzene solution of styrene by the anodic discharge of perchlorate and borotetrafluoride ions. The possibility that the three different mechanisms could occur simultaneously was demonstrated in the same system of acrylonitrile-styrene using a divided electrolytic cell. 

Iwai, S., T. Kakurai, and T. Noguchi Studies on acrylonitrile-styrene graft copolymerization onto cellulose by ceric salt. J. Soc. Text, and Cell. Ind. (Japan) 19, 547 (1963). 

A chemical crosslinking also seems possible in the acrylonitrile polymerization by a copolymerization activity of the nitrile group (20). In fact, we found a certain extent of acid hydrolysis in acrylonitrile-styrene popcorn copolymers, which could be an indication for crosslinking groups such as ... 

We will describe its use for controlling the styrene-acrylonitrile emulsion copolymerization system. Results concerning copolymer compositions, molecular characteristics and particle sizes will be compared to the corresponding ones from batch or semi-continuous processes. 

Watanabe62) studied systematically the copolymerization of ra-methacryloyl-polyoxyethylenes, with monomers such as acrylonitrile, styrene, butyl methacrylate, and methacrylic acid. It should be mentioned that the macromonomers that he prepared are very short so that no difficulties were encountered to isolate the graft copolymers formed. There are many applications for these graft copolymers, e.g. as additives in polyacrylonitrile films and fibers they cause improved antistatic properties. They have been tested as varnishes, coatings, and wood dimensional stabilization agents. 

Acrylonitrile-styrene-acrylate (ASA) polymers share obvious similarities with ABS but ASA was only developed in the 1960s. ASA polymers are essentially SAN polymers impact modified with an acrylate rubber. The earliest attempt to make ASA was by Herbig and Salyer of Monsanto [23] using butyl acrylate as the rubber phase. This work was then refined by Otto [24] and Siebel [25], both of BASF, who copolymerized butyl acrylate with butadiene to prepare the rubber phase. 

SAN is constituted of styrene and acrylonitrile units copolymerized statistically in the ratio 80 20 mol%. Previous studies on the photooxidation of PS [7,8] and PAN [3] have shown that the photooxidation rates of these polymers were very different PS degrades about 20 times faster than PAN. Consequently, the first steps of photooxidation of the copolymer SAN is presumed to involve mainly the styrene units. SAN samples have been irradiated and analyzed under the same conditions as PS samples. 

Bulk addition multipolymerization kinetics occurs when two monomers are employed. Bulk free-radical homopolymerizations and copolymerizations that are implemented in REX include a) styrene-acrylonitrile, styrene-methyl methacrylate, styrene-acrylamide b) methyl methacrylate-acrylonitrile, ABS c) acrylate ester mixtures d) ethyl acrylate-methacrylic acid and mixtures with other monomers e) methyl methacrylate f) 8-caprolactone and, n-isopropylacrylamide-acrylic... 

Monomer 13 homopolymerization was very sluggish, but it copolymerized in good yields with acrylonitrile, methyl methacrylate, and /V-vinyl-2-pyrrolidonc (Scheme 1.6).59,61 However, styrene copolymerizations required several subsequent reinitiations to get good yields of copolymers. The reactivity ratios obtained in 13/styrene copolymerizations were fj = 0.16 and r2 = 1.55 (when Mj = 13),61 giving values of Q = 1.66 and e = —1.98 for monomer 13 in direct accord with the Qe values found for monomers 1, 8, 10, 11, and 12, as discussed earlier.61... 

To demonstrate the livingness of styrene-acrylonitrile random copolymerizations, TEMPO (0.084 g) and BPO (0.101 g) were dissolved in 30 mL of styrene and 10 mL of acrylonitrile. The reaction mixture was stirred and purged with argon. The flask was sealed, lowered into a oil bath at 125 C and the mixture allowed to reflux. Periodically the flask was removed from the bath, cooled and a sample withdrawn for GPC analysis. To measure the composition of the copolymers, a series of polymerizations taken to low conversion were done in a Parr pressure reactor. The total moles of monomer were kept constant at 0.55, and the relative amounts of the two monomers were adjusted to vary the mole fraction of acrylonitrile from 0.1-0.9. 

Examples of this type are methyl methacrylate-acrylonitrile, styrene-methyl methacrylate, and acrylonitrile—aerylamide eopolymers. It is also possible that monomers involved in the copolymerization process... 

Methyl methacrylate has been copolymerized with a wide variety of other monomers, such as acrylates, acrylonitrile, styrene, and butadiene. Copolymerization with styrene gives a material with improved melt-flow characteristics. Copolymerization with either butadiene or acrylonitrile, or blending PMMA with SBR, improves impact resistance. Butadiene-methyl methacrylate copolymer has been used in paper and board finishes. 

Barex The trade name for BP Chemical International s (Sohia Division) family of acrylonitrile (AN) copolymerized styrene plastic. It was the first technically and commercially successful carbonated beverage bottle to be produced and was used in producing the first Coca-Cola stretched injection blow-molded bottles. See Coca-Cola bottle, barium oxide (BaO) A white to yellow powder that melts at 192°C. It forms a hydroxide with water and is used as a dehydrating agent. Also called barium monoxide or barium protoxide. 

Most comonomers differ from styrene in polarity and reactivity. A desired copolymer composition can be achieved, however, through utilization of copolymerization parameters based on kinetic data and on quantum-chemical considerations. This is done industrially in preparations of styrene-acrylonitrile, styrene-methyl methacrylate, and styrene-maleic anhydride copolymers of different compositions. 

Considerable quantities of styrene are used in producing copolymerisates and blends, as, for example, in the production of copolymers with acrylonitrile (SAN), terpolymers from styrene/acrylonitrile/butadiene (ABS polymers) or acrylonitrile/styrene/acrylic ester (ASA), etc. The glass transition temperature of poly (styrene), 100 C, can be increased by copolymerization with a-methyl styrene. What are known as high impact poly (styrenes) are incompatible blends with poly(butadiene) or EPDM, which are consequently not transparent, but translucent. For this reason, pure poly (styrenes) are occasionally called crystal poly (styrenes). 

Example 3.37 Radical Copolymerization of Styrene with Acrylonitrile (Azeotropic Copolymerization)... 

The original approach for this scheme was based on copolymerizations of styrene with acrylonitrile and with other acrylic monomers [149]. In developing a more general approach, however, Jenkins concluded that while in principle, a general procedure involves fewer assumptions, in practice much of the utility is lost. He proposed that it is convenient in practice to employ from styrene copolymerizations. 

It was reported by Barb in 1953 that solvents can affect the rates of copolymerization and the composition of the copolymer in copolymerizations of styrene with maleic anhydride [145]. Later, Klumperman also observed similar solvent effects [145]. This was reviewed by Coote and coworkers [145]. A number of complexation models were proposed to describe copolymerizations of styrene and maleic anhydride and styrene with acrylonitrile. There were explanations offered for deviation from the terminal model that assumes that radical reactivity only depends on the terminal unit of the growing chain. Thus, Harwood proposed the bootstrap model based upon the study of styrene copolymerized with MAA, acrylic acid, and acrylamide [146]. It was hypothesized that solvent does not modify the inherent reactivity of the growing radical, but affects the monomer partitioning such that the concentrations of the two monomers at the reactive site (and thus their ratio) differ from that in bulk. 

Buna rubber n. A brand of synthetic rubber made by polymerizing or copolymerizing butadiene with another material, as acrylonitrile, styrene, or sodium. 

Chemical modification. From among a number of procedures, the method of graft copolymerization of fibers by monomers, such as acrylic acid, vinylpyridine, acrylonitrile, styrene and vinyl acetate was introduced into pilot production. 

Styrene Copolymers. Acrylonitrile, butadiene, O -methylstyrene, acrylic acid, and maleic anhydride have been copolymerized with styrene to yield commercially significant copolymers. Acrylonitrile copolymer with styrene (SAN) is the largest volume styrenic copolymer and is used in applications requiring increased strength and chemical resistance over PS. Most of these polymers have been prepared at the crossover or azeotrope composition, which is ca 24 wt% acrylonitrile (see Copolymerization). 

Commercial styrene-acrylonitrile copolymers (SAN) generally contain 20—30% acrylonitrile. Various methods may be used to prepare these materials. In one method a mixture of styrene and acrylonitrile is copolymerized in solution using techniques similar to those described previously for the homopolymer (Section 3.2.3.2). 

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