بررسي اثر نسبت فاز آلي به آبي و نوع آغازگر بر پليمرشدن امولسيوني كوپليمر وينيل استات -اتيلن

The Effect of Aqueous/Organic Phase Ratio and Type of Initiator on Emulsion Polymerization of Vinyl Acetate-ethylene Copolymer

Batch emulsion polymerization of vinyl acetate-ethylene in a pressurized gas-liquid system was performed. The effect of the initiator type (redox and thermal) and aqueous phase-to-organic phase ratio (A/O) was investigated. By replacing redox initiator with a thermal type of initiator, vinyl acetate conversion was increased while ethylene content of the copolymers showed a decreasing trend. Using three different A/O ratios of 30, 40 and 50 weight percent of vinyl acetate it was found that reaction conditions at 40 wt% produce copolymers with adequate conversion and ethylene content. This observation was attributed to the higher viscosity in higher monomer content and lower rate of polymerization with lowest monomer weight percent. The relationship between the ethylene content and intrinsic viscosity of the copolymers and their influence on the glass transition temperature of the synthesized copolymers is investigated.