乳聚天然胶乳IPN型热塑性弹性体的合成

Preparation of thermoplastic elastomer using latex interpenetrating network polymerization

以天然胶乳为种子乳液 ,苯乙烯 (St)、甲基丙烯酸甲酯 (MMA)、丙烯腈 (AN)、丙烯酸异冰片酯 (IBA)等单体或它们的共混物为互穿单体 ,油酸为稳定剂 ,二乙烯苯为交联剂 ,叔丁基过氧化氢 /四乙烯五胺为氧化还原引发体系 ,采用种子乳液聚合法制备出乳胶粒外壳呈硬聚合物梯度分布的复合乳液 ,经絮凝干燥得固体聚合物。考察了互穿单体的种类和用量、交联剂用量及溶胀时间等对材料力学性能的影响。结果表明 ,溶胀时间对聚合物力学性能没有影响 ;交联剂对应硬单体的摩尔分数为 1 0 %时 ,聚合物力学性能最佳 ;硬单体配伍及其用量明显影响互穿聚合物的力学性能 ,其中IBA +St+AN为硬单体组分且质量分数为 2 0 %时 ,材料的力学性能较好 ,其拉伸强度8 7MPa ,撕裂强度 32 6kN/m ,伸长率 30 0 %～ 60 0 %。聚合物可热塑性加工。

A new kind of core shell latex based on natural latex as “seed” with hard block gradient distribution was synthesized through two stage emulsion polymerization in order to prepare interpenetrating network(IPN). Styrene (St), methyl methacrylate (MMA), acrylonitrile (AN), isobornyl acrylate (IBA), one or two or three was selected as monomer for hard block and oleic acid as emulsifier, divinyl benzene as crosslinker, t butyl hydroperoxide/tetraethylene pentamine as Redox initiation system. The effects of monomers, crosslinker on mechanical properties were studied. The mechanical properties of the final product showed the tensile strength is 8 7 MPa and elongation 300%～600%. The resulting materials are able to be reprocessed like thermoplastic.