超细NaHCO_3的制备及在聚丙烯微孔发泡材料中的应用

Preparation of Ultrafined NaHCO_3 and Used in PP Microcellular

选用价廉无毒的碳酸氢钠(NaHCO_3)作为发泡剂,利用反溶剂重结晶法进行细化,成功地制备出超细NaHCO_3粒子。最佳制备条件为:使用10%质量分数的NaHCO_3,蒸馏水与无水乙醇体积比1∶14,搅拌速度1100 r/min,制备温度-5℃,入料速度1 m L/min。纳米粒度分析仪测试表明NaHCO_3平均尺寸为143.2 nm,尺寸分布非常窄。将超细NaHCO_3添加到聚丙烯(PP)中进行微孔发泡,使用扫描电镜观察并使用Nano Measurer分析泡孔尺寸,表明当NaHCO_3用量为4.5 phr时,其泡孔平均尺寸低至0.47μm,泡孔尺寸标准方差仅为0.16μm,低于任何文献报道值。力学性能较优,其中拉伸强度下降了9.6%,而冲击强度提高了47.8%,弯曲强度提高了20.2%。这种使用普通注塑机获得高质量低成本的微孔发泡材料,对微孔材料的制备和应用有一定的意义。

Cheap and nontoxic sodium bicarbonate （NaHCO3） was chosen as blowing agent, and ultrafined NaHCO3 particles were successfully prepared by anti-solvent recrystallization method. When the mass concentration of NaHCO3 is 10%, the volume ratio of water and ethanol is 1：14, the speed of stirring is 1100 r/min, the preparation temperature is - 5 ℃, the feed rate is 1 mL/min, the optimal preparation conditions are determined. The average particles size of ultrafined NaHCO3 is 143.2 nm along with a narrow size distribution which was measured by laser particle size analyzer. The ultrafined NaHCO3 was mixed with PP to prepare microcellular PP, and SEM was used to observe these microcellulars and Nano Measurer software was applied to analyze these cells size. The results show that when the NaHCO3 amount is 4.5 phr, the average size is 0.47μm, the cell size standard deviation is only 0.16 μm, lower than any reported literature. The microcellular PP remains excellent mechanical properties than the unfoamed, the impact strength and the flexural modulus enhances 47.8% and 20.2% respectively, whereras the tensile strength slightly drops 9.6 %. Excellent cell structure, good properties and cheap microcellular PP was successfully prepared by ordinary injection molding machine, which has a significant effect on the development and application of microcellular in the future.