Studies of L-ascorbic acid addition to styrene miniemulsion polymerizations.

摘要

Stable Free Radical Polymerization (SFRP) employs a nitroxyl, such as TEMPO, to prepare "living" polymers with controlled molecular weight and macromolecular structure. The addition of nitroxides adds complexity to emulsion kinetics and therefore in order to examine the effect of certain variables a more simplified system is preferred. The effects of surfactant type, specifically Sodium dodecylbenzenesulfonate (SDBS) and DOWFAX 8390, and the addition of L-ascorbic acid were investigated within emulsions and miniemulsions initiated solely by styrene thermal polymerization, with the primary goal of applying the knowledge gained to SFRP. Differences in surfactant performance were observed and investigated. For example, while in miniemulsion higher polymerization rates were obtained using SDBS as the surfactant when compared to DOWFAX 8390, in emulsion similar rates were obtained. Surface tension analysis revealed that while SDBS is more effective at reducing the surface/interfacial tension, DOWFAX 8390 is more efficient at stabilizing polymer particles. (Abstract shortened by UMI.)