Additives styrene grafting

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). 

Table I. Synergistic Effect of Acid and TMPTA as Additives in Grafting Styrene to Polyethylene Film Initiated by Ion is ing Radiation8 ...

Table III. Comparison of Acid with Inorganic Salts and Urea as Additives in Grafting of Styrene to the Polyolefins Initiated by Ionising Radiation3...

Table IV. Synergistic Effect of TMPTA with Urea and Inorganic Salt Additives in Grafting Styrene to Polypropylene Initiated by Ionising Radiation3...

Additives in Grafting Styrene to Polyethylene and Cellulose Initiated by UVa... 

Effect of the Addition of Carbon Tetrachloride to the Styrene Grafting Solution, Preirradiation Method to Rayon Fibers. (Adapted from Min and Inagaki) Ref. 13. 

Table II. Comparison of Divinylbenzene (DVB) with Mineral Acid as Additives in Styrene Grafting to Polyethylene ...

The mechanismsof the acid effect has been extensively investigated (12-15, 21) whereas the current use of the polyfunctional monomers as enhancement additives in grafting is novel. The role of acid in these radiation grafting reactions is complicated and there is evidence that a number of pathways contribute to the overall enhancement effect. Thus mineral acid, at the levels used, should not affect the physical properties of the system such as swelling of the trunk polymer or precipitation of the grafted polystyrene chains. Instead evidence (12) indicates that the acid effect is due to a radiolytic increase in G(H) yields in the monomer-solvent system due to reactions similar to those depicted in Equations 1 and 2 for styrene-methanol. 

In addition to ABS, with polybutadiene as the elastifying component, there is another forerunner among the polymer products formulated for low-temperature impact resistance, PVC-U. Elastifying ligands include EVAC, EVAC/VC graft polymer, PAEA C (polyacrylic acid ester/vinyl chloride copolymer), ACE (acrylic ester/MMA graft polymer) as well as the chlorinated low-pressure polyethylene PE-C in use for over 35 years. All of the polymer blends listed here are suitable for outdoor applications since they contain no unsaturated components. Polybutadiene-modified products are better suited to interior applications, for example MBS, a methylmethacrylate/butadiene/styrene graft polymer [55]. 

Some base polymers such as PTFE do not swell weU in any common solvent. For this reason, the grafting reaction is performed in aqueous medium. Hegazy et aL [ 112] investigated the effect of various solvents on the radiation grafting of methacryhc acid onto PTFE film. The authors demonstrated that distilled water and methanol/water mixture (30/70 wt. %) are the most suitable solvents since the mixture swells the grafted regions. The increase in DG upon addition of water to isoproponal was emphasized for styrene grafting into FEP [76]. 

Addition of rubbery materials, however, does improve the impact resistance of polystyrene. This is therefore done extensively. The most common rubbers used for this purpose are butadiene-styrene copolymers. Some butadiene homopolymers are also used, but to a lesser extent. The high-impact polystyrene is presently prepared by dissolving the rubber in a styrene monomer and then polymerizing the styrene. This polymerization is either done in bulk or in suspension. The product contains styrene-butadiene rubber, styrene homopolymer, and a considerable portion of styrene-graft copolymer that forms when polystyrene radicals attack the rubber molecules. The product has very enhanced impact resistance. 

PA-6/PP-g-(S)MA/PS SEM/selective solvent extraction/ effect of order of component addition/PP grafted with MA in presence of styrene monomer Li et al. 2011c... 

Polyethylene, PE, blended with immiscible polymers (e.g., PVC, PIB, PS) was compatibilized by addition of graft copolymer (e.g., styrene or vinyl acetate grafted on PE)... 

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