ISSN:
0887-624X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The effect of alkyl substituents on cationic polymerization of styrene with p-methoxybenzyldialkysulfonium salts was studied. p-Methoxybenzyl tetramethylene (1), dimethyl (2), diethyl (3), dibuty (4), and diisopropylsulfonium salts (5) were synthesized by the reaction of p-methoxybenzyl bromide with the corresponding sulfides, followed by exchange of the counter anion Br- with SbF-6. These sulfonium salts served as potent cationic thermal initiators of which activity was estimated by the bulk and solution polymerizations of styrene. The bulk polymerizations with 1-4 (0.1 mol %) for 30 min gradually proceeded at 30-50°C, but the exothermic polymerization occurred vigorously at 40-60°C. The Polymerization with 5 took place exothermically even at room temperature. Temperature-conversion curves of the polymerizations for 30 and 5 min revealed that the activity of the sulfonium salts was in the following order: 5 〉 4 〉 3 〉 2 ≈ 1. This order was explained by the order of the bulkiness of the alkyl substituents on the sulfur atom. Number-average molecular weight (M̄n) of polystyrene obtained by the polymerization undergoing no exothermic process was in a range of 6600-16000, which depended on the structure of the alkyl substituents: the more bulky the substituent was, the higher M̄n was.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pola.1991.080290802
