Olefin polymerization in liquid sulfur dioxide initiated by m‐chloroperbenzoic acid. I. Homopolymerization of styrene and α‐methylstyrene

Abstract

Homopolymerizations of styrene (Sty) and α‐methylstyrene (AMS) in liquid sulfur dioxide were carried out in the temperature range from −10°C to −78°C, using m‐chloroperbenzoic acid as initiator. It is shown, through the effect of initiator concentration, temperature, and times of reaction on the conversion and molecular weight of the polymers, that AMS is more reactive than Sty because it requires a smaller amount of initiator for the same conversion to be reached, although the molecular weight of the resulting polymer is lower. A linear relationship has been observed for Sty between the degree of polymerization and the initiator concentration. Within the experimental conditions employed, the presence of polysulfones has been discarded by elemental analysis. The polymerization reactions are considered to be cationic in mechanism.

Relaxations of Poly(methyl methacrylate) Probed by Covalently Attached Anthryl Groups

“…The comonomer feed ratio was adjusted according to their reactivity ratios, which were determined through the Finemann-Ross and Kelen-Tudo ¨s methods, as described elsewhere. 27 After reacting for 24 h, the polymerization mixture was poured over 10 times the volume in methanol, and the precipitated material was filtered and dried overnight in a vacuum oven at 310 K.…”

“…The polymerization was carried out in toluene, typically 20% monomer/solvent (w/v) at 373−378 K. Benzoyl peroxide was used as initiator (1% peroxide/monomer w/w). The comonomer feed ratio was adjusted according to their reactivity ratios, which were determined through the Finemann−Ross and Kelen−Tudös methods, as described elsewhere . After reacting for 24 h, the polymerization mixture was poured over 10 times the volume in methanol, and the precipitated material was filtered and dried overnight in a vacuum oven at 310 K.…”

The preservation of �ankiri limestone in sulfur dioxide atmosphere byin situ polymerization of ethyl methacrylate

“…The SO 2 was freshly generated as the product of reaction between NaHSO 3 and H 2 SO 4 , dried over P 2 O 5 , and stored in steel cylinders. 8 The TBHP was obtained from Fluka Chemie AG. Ç ankiri limestone samples were cut in fixed dimensions of 5 ϫ 3 ϫ 2 cm 3 and dried in a furnace at 40°C until constant weight was reached.…”