高膨胀倍率低温热膨胀微球的制备

Preparation of Thermal Expansion Microspheres with High Expansion Rate and Low Expansion Temperature

采用悬浮聚合法,以低沸点异戊烷为发泡剂,丙烯腈(AN)、甲基丙烯酸甲酯(MMA)、甲基丙烯酸丁酯(BMA)、甲基丙烯酸羟乙酯(HEMA)为共聚单体,氢氧化镁为分散剂,制备了低起始发泡温度的低温热膨胀微球。通过动态光散射激光粒度仪、光学显微镜、扫描电子显微镜、热机械分析等表征方法对热膨胀微球的形貌及热膨胀性能进行对比分析,最终确定了影响微球发泡性能的主要因素为发泡剂用量、交联剂种类及聚合物组成。结果表明,当m(AN)∶m(MMA)∶m(BMA)∶m(HEMA)=2∶5∶1∶2、引发剂过氧化过氧化苯甲酰(BPO)质量分数为0.5%、交联剂邻苯二甲酸二丙烯酯(DAP)质量分数为0.3%、异戊烷质量分数为30%、聚合转速为400 r/min时,可制备出发泡温度为62.3~144.1℃,膨胀直径倍率为3.75的高膨胀倍率低温热膨胀微球。

Thermal expansion microspheres with low initial foaming temperature were prepared by suspension polymerization using isopentane as foaming agent,acrylonitrile(AN),methyl methacrylate(MMA),butyl methacrylate(BMA),hydroxyethyl methacrylate(HEMA)as comonomers,and magnesium hydroxide as dispersant.The morphology and thermal expansion properties of thermal expansion microspheres were compared and analyzed through the dynamic light scattering laser particle size analyzer,optical microscope,scanning electron microscope,thermal mechanical analysis and other characterization methods.The results show that thermal expansion microspheres with high expansion diameter ratio and low expansion temperature are prepared when m(AN)∶m(MMA)∶m(BMA)∶m(HEMA)=2∶5∶1∶2,the initiator BPO is 0.5%,the crosslinking agent DAP is 0.3%,isopentane is 30%,and the polymerization rotating speed is 400 r/min.The maximum expansion diameter ratio and the foaming temperature are 3.75 and 62.3~144.1℃,respectively.