ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Block copolymers have been synthesized by heating a polymer, containing peroxidic linkages, in the presence of another monomer. The peroxide groups were introduced into the first polymer by initiating the controlled polymerization of its monomer with phthalyl peroxide. Separation of the block copolymers from the two parent homopolymers was made possible by their different solubilities in selected solvents or their mixtures. Polystyrene (Mn = 1.00 × 105), prepared at 75°C. in bulk with 0.5% phthalyl peroxide, initiated the polymerization of methyl methacrylate at 100°C. in benzene solution. The two block copolymer components isolated were found by infrared analysis to contain 22 and 30% polystyrene with number average molecular weights of 4.3×105 and 3.0×105, respectively. Block copolymers were also obtained by heating styrene in benzene at 85°C. with polyvinyl acetate (Mn = 0.60 × 105), prepared in benzene solution at 70°C. with 0.5% peroxide. A 39% vinyl acetate-61% styrene block copolymer was isolated and found to have a molecular weight of 1.65×105. Intrinsic viscosities, μ values, and κ′ values for the block copolymers and related homopolymers were determined and are discussed in terms of composition, molecular weight, and poly-dispersity. Other experiments indicated that styrene-phthalyl peroxide polymers were unable to initiate vinyl acetate or vinylpyrrolidone polymerizations at 100°C. in significant amounts; this behavior is interpreted in terms of the stability of the radicals formed.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1955.120178304
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