ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The copolymerization of styrene (St) with acrylonitrile (AN) initiated with 2-methyl-2-undecanethiol (RSH) was investigated. Kinetic studies revealed that the initial rate of the copolymerization, which does not occur spontaneously in the absence of RSH, obeys the following expression: Rp ∝ [RSH]x, where x is 0,5 when [RSH] ranges from 3,4.10-4 to 3,4.10-3 mol/l and 0 when [RSH] is larger than 3,4.10-3 mol/l. The initial copolymerization rate, Rp, increases with increasing percentage of AN in the monomer feed. From the slope of ln Rp vs. 1/T, the apparent activation energy, Eapp, was calculated to be 17 kJ/mol in the temperature range of 30°C to 50°C. RSH is the only initiating species, and it also plays a role as chain-transfer agent. The value of Mw/Mn, which varies from 1,5 to 2,0, is typical of a free-radical poymerization. The reactivity ratios were calculated to be rSt = 0,42 ± 0,04 and rAN = 0,02 ± 0,03. It seems to be unnecessary to introduce a penultimate effect for explaining the experimental data.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1989.021900929
Permalink
