Distribution of end groups and comonomer of the acrylonitrile-vinyl acetate copolymer

✍ Scribed by Seiichi Ito; Chiharu Okada; Kensuke Kamada

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 364 KB
• Volume: 32
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1986.070320317

✦ Synopsis

The number average molecular weight and strong acid end groups (SAG) of fractionated polymers were measured for the acrylonitrile-vinyl acetate copolymers (93:7 in weight), which were prepared by continuous polymerization in aqueous medium with the persulfate-bisulfiteion redox system. Average number of SAG per polymer molecule was nearly 1 for fractionated portions of the polymers prepared under the polymerization conditions of water/monomer ratio in the range 4.0-2.5 in weight. No marked difference existed in comonomer content in fractions of these polymers. For unfractionated polymers prepared under the conditions of water/monomer ratio varied from 4.0 to 1.75, average number of SAG was roughly 0.8-1. The proportion of sulfoxy end groups to SAG was estimated to be roughly from 0.5 to 0.6 and increased slightly with increased bisulfite/persulfate ratio. Based on the above results, disproportionation and transfer to bisulfite-ion are considered to be the main processes of termination of polymer radicals in the studied range of polymerization conditions.