Miniemulsion polymerisation of a bifunctional macromonomer
2001
Hafsah M. G. | Daniels, E. S. | Klein, A. | El-Aasser, M. S.
Evaluation of the miniemulsion polymerisation of a hydmphobic bifunctional macromonomer was undertaken. The rate of polymerisation of the macromonomer was faster when the reaction was carried out using a water-soluble initiator, potassium persulphate, KPS, than when an oil-soluble initiator, 2,2’-azobis(isobutyronitrile), AIBN, was used. Unsaturation peaks were no longer observable in the 1H NMR spectrum of the reacted macromonomer when the gel content was -50%. In both cases, depending on the reaction time, cross-linked products were obtained. For the KPS-initiated homopolymerisation, 50% - 60% gel content was already obtained by (he first hour of reaction, while similar gel development in the macromonomer was only observed after 6 h ~ 12 h of polymerisation when AIBN was used. The polymerised macromonomer (using AIBN as initiator) exhibited a distinct physical change when water was removed, only when (he gel content was -50%, which- corresponded to a substantial loss of unsaturation peaks in the 1H NMR spectrum. The gel content remained low (< 10%) earlier in the polymerisation despite the steady increase in the reaction of the double bonds of the macromonomer.
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