Number of crosslinked monomer units per weight-average primary chain at the gel point in the emulsion polymerization of 1,3-dienes
✍ Scribed by Dannals, L. E.
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1970
- Tongue
- English
- Weight
- 976 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0449-296X
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✦ Synopsis
Abstract
Without new assumptions, it is demonstrated that at the gel point in mercaptanregulated, 1,3‐diene emulsion polymerizations, the number of crosslinked monomer units per weight‐average primary chain is larger than one. The divergence of this number from one increases as the nonrandomness of the crosslinked monomer units distribution and the heterogeneity of primary chain size increase. According to the available experimental data, this number ranges from 1.11 to 1.29. Crosslink density values and rate constants of crosslinking to propagation, which were calculated assuming this number to be one, are consequently increased. It is also demonstrated, for postulated systems, that this number may be larger or smaller than one, depending on the type of nonrandomness of the crosslinked monomer units distribution. In either case, the divergence of this number from one also increases as the nonrandomness of the crosslinked monomer units distribution and the heterogeneity of primary chain size increase.