PBD/PDMS共混物分散相的聚并捕获行为

Arrested Coalescence of Droplets in PBD/PDMS Blends

借助显微-剪切装置在线研究了低速剪切场下SiO2纳米粒子含量、分散相聚丁二烯(PBD)浓度和剪切速率对PBD/聚二甲基硅氧烷(PDMS)不相容体系中聚并捕获行为的影响.结果表明,聚并捕获所形成的液滴尺寸与形状规整度由粒子含量、分散相浓度和剪切速率等因素共同决定.在较低的SiO2纳米粒子含量或较高的分散相浓度下,PBD液滴在低剪切场下发生聚并捕获,形成尺寸较大、形状不规则的液滴.增加SiO2纳米粒子含量或减小分散相浓度,能够减小分散相的尺寸并提高分散相的规整度.增加剪切速率能有效地减小分散相的尺寸并提高分散相的规整度.

We investigated the effect of silica nanoparticle loading, dispersed phase fraction and shear rate on the arrested coalescence in immiscible blends of polybutadiene/polydimethylsiloxane（ PBD/PDMS） under sim-ple shear flow by an online optical-shear system. It was found that the size and regularity of the non-spherical PBD droplets resulted from arrested coalescence were determined by SiO2 nanoparticles loading, dispersed phase fraction and shear rate. At low SiO2 nanoparticle loading or high dispersed phase fractions, the coales-cence of PBD droplets induced at low shear rate can be arrested by the nanoparticles at the interface, leading to the formation of large and irregular droplets. Increasing SiO2 nanoparticles loading, decreasing dispersed phase fraction or increasing shear rate can greatly decrease the size of the PBD droplets and improve their regu-larity. The results should be closely related to SiO2 nanoparticles coverage at the interface of the PBD droplets.