| Abstrakt: |
Without any type of surfactant or dispersing agent, precipitation polymerization has great superiorities in both polymer synthesis and applications. In the present work, the polymerization of vinyl chloride (VC), n-butyl acrylate (BA), and vinyl acetate (VAc) are conducted in the precipitation polymerization system and series of their random terpolymers poly(vinyl chloride-co-n-butyl acrylate-co-vinyl acetate) (PCBV) are synthesized successfully. The effects of various polymerization conditions, including solvent polarity, temperature, initiator concentration, and monomer feed ratios on the polymerization kinetics, number-average molecular weight (Mn), and terpolymer composition are investigated systematically. The solvent and the monomer feed ratio are crucial factors not only for the polymer morphology, but also for the reaction kinetic. In the non-polar solvent such as n-hexane, the PCBV displays particle morphology when the composition of BA ratio lower than 10 wt%. Otherwise, the PCBV forms a uniform polymer phase and precipitates out from the mixture. In the polar solvent, e.g., dimethyl carbonate (DMC) and ethanol, the PCBV polymer maintains a slurry state either in low or in high monomer feed ratio. Impressively, VC based ternary copolymer that obtained in n-hexane has much lower Mn (<20 kDa) and much higher BA units mass fraction (>40 wt%) compared with emulsion and suspension polymerization. Additionally, the terpolymer can be easily separated by simple centrifugation. [ABSTRACT FROM AUTHOR] |
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