【摘要】 采用3种加料方式【间歇法、滴加苯乙烯（St）法及滴加预乳化液法】合成乙酸乙烯酯（VAc）/St乳液共聚物。考察了共聚合方式对VAc/St乳液共聚物相对分子质量及其组成分布的影响,间歇法所得乳液共聚物相对分子质量较大,分布较宽;而滴加预乳化液法较小,分布也较窄;滴加St法居中。m（VAc）/m（St）为7:3的乳液共聚物在30℃的四氢呋哺溶剂中Mark-Houwink常数为1.24×10^-3mL/g,扩张因子为0.86。更多还原

【Abstract】 The authors synthesized a kind of emulsion copolymer from vinyl acetate （VAc） and styrene （St） with 3 feeding procedures,i.e.adding initiator in batchwise,adding styrene dropwise and adding pre-emulsion drop- wise.The effects of copolymerization mode on molecular mass and composition distribution of the VAc/St latex were explored.The results reveal that the VAc/St latex synthesized by adding initiator in batchwise has the highest relative molecular mass and the widest distribution,whereas the VAc/St latex prepared by adding pre-emulsion dropwise has the lowest corresponding values among the three emulsion copolymers.The VAc/ St latex made by adding styrene dropwise possesses the intermediate values between the two.The VAc/St latex （mass ratio 7:3） in tetrahydrofuran at 30℃ has the Mark-Houwink constant of 1.24×10^-3mL/g and expan- sion factor of 0.86.更多还原