聚硅氧烷改性苯丙乳液──Ⅰ共混改性

Styrene-butylacrylate Copolymer Emulsion Modified by polysiloxane Ⅰ.Blending Modification

聚合物乳液的共混改性可以得到一些独特的性能，改性的效果取决于共混聚合物的相容性及其形态结构，也取决于共混乳液的稳定性。本文研究了聚硅氧烷改性苯丙乳液的稳定性，聚硅氧烷改性橡胶膜的形态结构、两相间相容性，及其对改性橡胶膜力学性能的影响。ＥＳＣＡ和ＳＥＭ结果表明改性橡胶膜中存在明显的相分离，聚硅氧烷在膜的表面富集；通过接枝共聚使苯丙乳液粒子中含有部分聚硅氧烷，或聚硅氧烷乳液粒子中含有部分苯丙共聚物，两者都能降低两相间的界面张力，改善两相间的相容性，从而明显提高改性橡胶膜的力学强度，但只有当聚硅氧烷分子链与苯丙分子链通过接枝和机械缠结，才能明显抑制有机硅分子链向膜的表面迁移。

Special properties may arise from blending of polymer emulsions,depending on the morphology and compatibility of the resulted blend,and on the stability of the blend dispersions.In this paper the stability of the emulsion blends of styrene-butylacrylate copolymer emulsions rnodified by polysiloxane emulsion, the morphology of the resulted rubber films and the compatibility of the two phases and the effect of modification on the mechanical properties of the rubber film were studied.The results of ESCA and SEM measurements showed an obvious phase separation and diffusion of the polysiloxane species towards the surface of the samples; it was shown that the compatibility of the two phases could be enhanced by lowering the interfacial tension between the two phases by grafting silane onto the styrene-butylacrylate copolymer emulsion particles or styrene-butylacrylate onto the polysiloxane emulsion particles,and the tensile strength of the resulted film increased.However,diffusion of the polysiloxane chains towards the surface of the films could only be significantly restricted by decreasing the molecular mobility of the polysiloxane phase by grafting and mechanically entangling.