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采用半连续种子乳液聚合法,保持壳层玻璃化转变温度(Tg)不变的情况下制备了3种不同核层Tg(分别为57℃、67℃、77℃)的聚丙烯酸酯乳液。用旋转流变仪研究了核层Tg及填料CaCO3对塑溶胶流变及凝胶固化行为的影响并用动态光散射(DLS)、扫描电镜(SEM)分别对乳胶粒子的粒径大小及分布、粒子形貌和塑溶胶的胶膜表面进行表征。测试结果表明:增塑后体系黏度随着剪切速率的增大而减小,呈假塑性流体特性;壳层Tg不变的情况下,核层Tg越高增塑后体系对应的凝胶点温度越高;随着填料CaCO3添加量的增加,增塑后体系粘弹性都增大,但凝胶点温度不会发生改变。
Three kinds of polyacrylate emulsions with different core layers (57 ℃, 67 ℃, 77 ℃, respectively) were prepared by semi-continuous seed emulsion polymerization while keeping the shell glass transition temperature (Tg) unchanged. The influence of Tg and filler CaCO3 on the rheological and gelation behavior of plastisols was investigated by using a rotating rheometer. Particle size and distribution of the latex particles were measured by dynamic light scattering (DLS) and scanning electron microscopy (SEM) Morphology and plastisol film surface were characterized. The results show that the viscosity of plasticized system decreases with the increase of shear rate and exhibits pseudoplastic fluid properties. When the shell Tg is constant, the higher the Tg of the core layer is, the more the gel point With the increase of filler CaCO3, the viscoelasticity of the system increases after the plasticization, but the gel point temperature will not change.