Butadiene copolymer grafted with

Selected blends of styrene-acrylonitrile copolymer (30 to 55%), a styrene-butadiene copolymer grafted with styrene and acrylonitrile (45 to 70%), and a coal-tar pitch (0 to 25%), were prepared. Physical properties of the experimental blends were determined and statistical techniques were used to develop empirical equations relating these properties to blend composition. Scheff canonical polynominal models and response surfaces provided a thorough understanding of the mixture system. These models were used to determine the amount of coal-tar pitch that could be incorporated into ABS compounds that would still meet ASTM requirements for various pipe-material designations. ... 

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 poly butadiene, polybutadiene grafted with acrylonitrile and styrene, and styrene-acrylonitrile copolymer. The presence of graft polymer is essential since straightforward 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. 

Styrene and acrylonitrile copolymer Styrene, butadiene and styrene copolymer Styrene, ethylene, butylenes and styrene copolymer Styrene, ethylene, butylenes and styrene copolymer grafted with glycidyl methacrylate Styrene, ethylene, butylenes and styrene copolymer grafted with maleic anhydride Styrene maleic anhydride Syndiotactic polystyrene... 

The term ABS was originally used as a general term to describe various blends and copolymers containing acrylonitrile, butadiene and styrene. Prominent among the earliest materials were physical blends of acrylonitrile-styrene copolymers (SAN) (which are glassy) and acrylonitrile-butadiene copolymers (which are rubbery). Such materials are now obsolete but are referred to briefly below, as Type 1 materials, since they do illustrate some basic principles. Today the term ABS usually refers to a product consisting of discrete cross-linked polybutadiene rubber particles that are grafted with SAN and embedded in a SAN matrix. 

FIGURE 13.2 Calculated relation between the solubility parameter and glass transition temperature (Jg) for a variety of ethylene-propylene copolymers (EPMs) grafted with polar monomers the window for rubbers with an oil resistance similar to or better than hydrogenated acrylonitrile-butadiene copolymer (NBR) (20 wt% acrylonitrile) is also shown. 

M.K. Laughner, Molding compositions with methyl (meth)acrylate-butadiene-styrene graft copolymers, US Patent 5 087 663, assigned to The Dow Chemical Company (Midland, MI), February 11,1992. 

H.P. Siebel and H.-W. Otto, Styrene- acrylonitrile copolymers blended with graft copolymers of styrene onto butadiene-alkyl acrylate-vinyl alkyl ether terpolymers, US Patent 3280219, assigned to BASF AG, October 18,1966. 

The composition of the grafted side chain copolymer has also been determined by Sakurada (113) and found to be different from the normal copolymer formed with acrylonitrile and butadiene. With styrene the grafted copolymers were found to be richer in acrylonitrile than the normal copolymer. Similar differences were found by Resting (114) with methyl methacrylate and styrene grafted to cotton and by Odian et al. (115) with grafting mixed monomers to Teflon and to polyethylene. It is believed that one monomer may be preferentially sorbed or diffused faster than the other, leading to a different monomer ratio at the actual site of grafting. 

The mechanical degradation and production of macroradicals can also be performed by mastication of polymers brought into a rubbery state by admixture with monomer several monomer-polymer systems were examined (10, 11). This technique was for instance studied for the cold mastication of natural rubber or butadiene copolymers in the presence of a vinyl monomer (13, 31, 52). The polymerization of methyl methacrylate or styrene during the mastication of natural rubber has yielded copolymers which remain soluble up to complete polymerization vinyl acetate, which could not produce graft copolymers by the chain transfer technique, failed also in this mastication procedure. Block and graft copolymers were also prepared by cross-addition of the macroradicals generated by the cold milling and mastication of mixtures of various elastomers and polymers, such as natural rubber/polymethyl methacrylate (74), natural rubber/butadiene-styrene rubbers (76) and even phenol-formaldehyde resin/nitrile rubber (125). 

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... 

Comparison of Methyl Methacrylate-Butadiene-Styrene with Acrylonitrile-Butadiene—Styrene Graft Copolymers... 

The same conclusion is found when the copolymer is prepared using large quantities of dichloroethane and the precipitation step occurs for higher n value. Consequently we must deduce, in such cases, that added PVC is different from PVC contained in the copolymer. One is justified in concluding that PVC is grafted by butadiene copolymer, (analysis verifies this) and that all PVC chains are grafted in the samples prepared with high dichloroethane ratios. 

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. 

Copolymers of styrene include a large group of random, graft, and block copolymers. Those with a high proportion of acrylonitrile used in barrier films as well as others such as methacrylic-butadiene-styrene copolymer (MBS) plastic is used as modifiers in PVC, SAN, ABS, ASA, etc. The styrene-acrylonitrile copolymer (SAN) is the most important when considering volume and number of applications. 

The relative amounts of the two processes (a) and (b) depend on the nature of the double bond. For example, the process (b) predominates when the double bond is more reactive. Although the method yields graft copolymer mixed with homopolymer, it has found successful industrial applications, as in the production of HIPS mentioned above and ABS copolymer made by copolymerizing styrene and acrylonitrile in the presence of poly( 1,3-butadiene). 

The impact strength of brittle thermoplastic materials is generally improved by adding small amounts of rubber, either pure or modified by grafting with the monomer or monomers constituting the matrix to be reinforced (1, 2, 3, 4, 5). As a rule, modification is achieved by monomer polymerization in the presence of the reinforcing elastomer, which is usually a butadiene polymer or copolymer (6, 7). 

Weather-resistant ABS can be obtained either by the incorporation of EVAc [Fukushima and Mitarai, 1971], or by replacing PB with EPDM, to obtain AES [Wefer, 1984, 1985, 1988]. Alternatively, blends of SAN with maleated EPDM and CPE may be used [JCim et al., 1994]. However, the non-weatherable styrenics are frequentiy prepared by dissolving an elastomer in methyl methacrylate, and either styrene or a-methylstyrene, then polymerizing them into methyl methacrylate-butadiene-styrene graft copolymers... 

Core-shell copolymer EPDM grafted with styrene-butadiene methacrylate or allyl cyanurate processability, high notched impact strength Siol et al., 1993... 

MBS with controlled size of the elastomeric particles transparent Copolymer of vinylchloride, alkyl acrylate, and vinyhdene chloride Butadiene-styrene-methylacrylate-ethylacrylate Core-shell crosslinked ABS with grafted onto it PMMA shell PB-grafted with MM A, styrene and vinyl acetate Poly(butadiene-co-butyl acrylate-co-styrene)... 

High Impact Polystyrene (HIPS) HIPS is a heterogeneous material produced by continuous bulk or bulk-suspension processes, in which a butadiene-based elastomer (polybutadiene (PB), or a block copolymer of styrene-butadiene) is first dissolved in styrene monomer (St) and the resulting mixture is then heated so that the polymerization proceeds either thermally or with the aid of a chemical initiator. At the molecular level, the product is a mixture of free polystyrene (PSt) chains and elastomer chains grafted with PSt side chains. The process yields a continuous (free) PSt matrix containing... 

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