以单分散P(DC-TMPTA)聚合物微球为Pickering乳液稳定剂制备石蜡乳液和石蜡微球

Preparation of Pickering Emulsion of Paraffin Wax and Microspheres Using Polymer Particles as Pickering Stabilizer

以三羟甲基丙烷三丙烯酸酯(TMPTA)和1-十二烯(DC)为单体,不使用任何乳化剂或分散稳定剂,通过沉淀聚合制备了高度单分散P(DC-TMPTA)的聚合物微球颗粒.以此聚合物微粒为Pickering稳定剂,不添加任何化学助剂,以乙醇-水混合介质在70℃下通过恒速振荡制得了单分散石蜡Pickering乳液.将该体系迅速降温至石蜡熔点之下,制得了窄分布的固体石蜡微球.研究了连续相水含量、振荡频率及稳定粒子尺寸对Pickering乳液及石蜡微球的影响,优化了石蜡乳液和微球的制备条件.利用扫描电子显微镜对石蜡微球的表面和内部形貌进行了表征,结果表明P(DC-TMPTA)微球全部聚集在石蜡液滴和固化后的石蜡微球表面.基于石蜡微球和聚合物稳定粒子的尺寸,计算了不同条件下石蜡微球表面聚合物粒子的数量.通过聚合物粒子在石蜡-乙醇和水混合溶液界面的三相接触角以及石蜡-乙醇和水混合溶液界面张力的测定,计算了聚合物粒子在石蜡-乙醇和水混合溶液界面吸附能,为解释该体系Pickering乳液的稳定性提供了理论支持.

Polymer particles were prepared through precipitation polymerization of trihydroxymethyl propane triacrylate（ TMPTA） with 1-dodecene（ DC） in binary solvent of ethanol-water（ Et OH-H2 O） without any surfactant and stabilizer. The particles of P（ DC-TMPTA） were used to prepare Pickering emulsion of paraffin wax in a mixture of Et OH-H2 O by simple shaking at 70 ℃,above the melting point of the wax. By rapidly cooling down the system to temperature far below the melting point of the wax,wax microspheres with narrow size distribution were obtained. The process was optimized with regard to the composition of Et OH-H2 O,shaking rate and the size of P（ DC-TMPTA） particles. Morphology of the wax microspheres was examined by SEM,showing the wax spheres were covered by a layer of P（ DC-TMPTA） particles. The size of the wax spheres was easily adjustable,from about 50 μm to 480 μm,by changing the shaking rate or the amount and the size of the polymer particles. This process is featured by the absence of any additives except the free radical initiator in the preparation of P（ DC-TMPTA） particles. This work provides therefore a novel pathway to the fabrication of uniform and clean wax microspheres.