应用于橡胶补强的活性纳米高岭土制备

Preparation of Activated Nano-sized Kaolin Clay as Styrene Butadiene Rubber Filler

采用化学插层-超细研磨-酸侵渍活化-干燥-表面改性的方法有效地制备了活性纳米高岭土。结果表明:通过化学插层与超细研磨的复合方法可制备70%的颗粒小于100 nm的高岭土,其片厚为10～30 nm。与单纯采用机械研磨的方法相比,该复合方法可以降低超细研磨所需的能耗。经酸侵渍活化处理可增大活性纳米高岭土的比表面积,但未破坏高岭土特有的层状结构。在活性纳米高岭土表面包覆十六烷基三甲基溴化铵和含氢硅油,可使其具有良好的亲油疏水性能。另外,对比喷雾干燥方法,经共沸蒸馏干燥的活性纳米高岭土粉体具有更好的分散性,制得的活性纳米高岭土作为丁苯橡胶的补强填料可明显提高其拉伸强度和伸长率,并缩短硫化时间。

An activated nano-sized kaolin clay was prepared via an effective process with various methods such as chemical pre-intercalation, ultra-fine grinding, acid etching, drying and surface modification with cetyltrimethyl ammonium bromide （CTAB） and hydrogen silicone. The results show that the micron-sized kaolin clay that is pre-intercalated with urea is ground in a high-energy density stirred bead mill to prepare the nano-sized particles with the fineness of 70% 〈 100 nm and the lamella thickness of 10-30 nm effectively. This hybrid method could reduce the energy consumption in the preparation of the nano-sized kaolin clay, compared to the single ultra-fine grinding method. The acid etching treatment increased the specific surface area of the activated nano-sized kaolin clay without the destruction of the layered structure. The particles coated with CTAB and hydrogen silicone oil appeared a superior hydrophobicity. The azeotropic distillation drying could produce the well-dispersive activated nano-sized kaolin clay, compared to the spray drying. In addition, the as-prepared activated nano-sized kaolin clay could be used as a styrene butadiene rubber filler to improve the tensile strength and rate, and reduce the vulcanizing time.