关键词: 种子聚合, 胶粒形态, 胶膜结构, 丙烯酸丁酯, 醋酸乙烯酯

Abstract: Homopolymer latexes of polyvinyl acetate (PVA) and polybutyl acrylate(PBA)and their seeded latexes using respectively PVA and PBA as seed were prepared by emulsion polymerization. In order to investigate particle morphologies of various seeded latexes, a selective staining technique using phosphotungstic acid(PTA) under transmission electron microscopy (TEM) observation as well as particle surface property characterization by soap titration were used. It was shown that latex particles of type PBA-PVA core-shell could be well formed by pouring VAmonomer into PBAseed latex, and that while BAwas added into PVA seed latex and initiated, PVA-PBA core-shell latex could not be obtained. This is attributed to the fact that PVAis more hydrophilic than PBA. By putting drops of water on the surface of the latex films prepared from above latexes at 40℃, water-resistance of the films was experimentally measured by reading "turbidity time" of the transparent films. Results showed that PVA films had a much shorter "turbidity time" than PBAdue to its larger hydrophilicity. It is observed that water-resistance of the seeded latex film of PBA-PVA (PBA as seed) was very similar to that of PVA, and that of PVA-PBA(PVA as seed) was significantly different from those of PVA and PBA. It is concluded that particle morphology was unchanged during film formation under the present experimental conditions.

Key words: Seeded polymerization, Particle morphology, Film structure, Butyl acrylate, Vinyl acetate