| 摘要 |
1455334 Expandable styrene polymer compositions MONTEDISON SpA 22 Feb 1974 [22 Feb 1973] 8213/74 Headings C3C and C3P Expandable styrene polymers are made by polymerizing styrene with optionally not more than its weight of a vinyl or vinylidine monomer, in the presence of 0À001-0À5% by wt. of at least one compound which is of formula where R<SP>1</SP> and R<SP>11</SP> are optionally halogensubstituted C 1-6 alkyl groups, R<SP>111</SP> and R<SP>1111</SP> are C 1-8 hydrocarbon groups which are fully or partially halogenated, and n is 1-5, an expanding agent being added to the styrene during or after its polymerization. In the example styrene is polymerized in aqueous suspension in the presence of a brominated compound of formula an initiator (a mixture of tert.-butyl peroxide and tert.-butyl perbenzoate), a suspending agent (an acrylic acid/2-ethylhexylacrylate), sodium chloride and as expanding agent a mixture of n- and iso-pentane. The expandable polymer particles were screened, pre-expanded using steam, aged and then moulded into blocks using steam. |
