A one-pot method for the preparation of latices of telechelic oligomers, by ozonolysis of latices of polymers containing main-chain unsaturation
✍ Scribed by J. R. Ebdon; S. Rimmer
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 175 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Poly(methyl methacrylate-co-butadiene), Poly(butyl methacrylate-co-butadiene) and Poly(methyl methacrylate-co-2,3-dimethyl butadiene) latices (a.k.a. latexes) were prepared by monomer-starved emulsion polymerization. The polymerizations were followed by GPC. It was found that the molecular-weight distribution did not alter significantly with conversion if the polymerizations were carried out at a feed rate of 0.03 cm 3 s 01 per 1000 cm 3 of reaction medium and a temperature of 70ЊC. Slower rates of monomer addition led to broadening of the molecular-weight distribution. The resultant latices were swollen with varying amounts of toluene. Ozonolysis of the swollen and nonswollen latices yielded latices of polymer ozonides. Oxidation, with selenium oxide/hydrogen peroxide reagent, converted the ozonides to latices of carboxylic acid or methyl ketone ended telechelic oligomers. It was found that the molecular weights of the oligomers were a function of toluene concentration. Colloidal stability was found to be a function of end-group structure. Thus, carboxylic acid end groups impart extra stability to the colloid while methyl ketone end groups do not.