| 摘要 |
1,243,197. Polymerizing styrene. BRITISH PETROLEUM CO. Ltd. 9 Jan., 1969 [18 Jan., 1968], No. 2704/68. Heading C3P. Styrene is polymerized, in the absence of an alkyl methacrylate, using an initiator system having at least three components under a continuously increasing programmed temperature cycle in the range 50-150‹ C., the first component having a half life of 1-15 hours at 70‹ C. and less than 1 hour at 100‹ C., the second having a half life of 1-15 hours at 100‹ C. and 1-4 hours at 115‹ C. and the third having a half life of 15-30 hours at 100‹ C. 0À1-10 hours at 130‹ C. Examples of the three components are (1) lauroyl or octanoyl peroxides, p - chlorobenzoyl peroxide, 2,4 - dichlorobenzoyl peroxide, benzoyl peroxide or di-isopropyl peroxy-dicarbonate (2) 1,1-di-tbutyl peroxy-3,5,5 trimethyl cyclohexane, tbutyl - peracetate, cyclohexanone peroxide or t-butyl peroxyisopropyl carbonate (3) t-butyl perbenzoate, dicumyl peroxide, di-t-butyl peroxide or di-t-butyl perphthalate. The process can also be applied to the copolymerization of styrene with divinylbenzene. The process can be carried out in an aqueous suspension the suspending agent being polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl starch a styrene-maleic anhydride copolymer or polyvinyl pyrrolidone. The suspension may also contain a wetting agent e.g. sodium caproate or oleate, long chain alkyl sulphate or sulphonate, sodium salt of an alkyl phosphate or the reaction product of tertiary butyl hydroperoxide and sodium formaldehyde sulphoxylate. |
