滑石粉对微孔发泡木粉/聚丙烯复合材料结晶行为及泡孔结构的影响

以滑石粉为成核剂,超临界CO_2为发泡剂,采用间歇釜式方法制备微孔发泡木粉/聚丙烯复合材料。采用DSC、XRD和SEM对微孔发泡木粉/聚丙烯复合材料的结晶行为与泡孔结构进行了测定与分析。结果表明:滑石粉的添加能够提高微孔发泡木粉/聚丙烯复合材料的结晶温度,诱导产生不完善的α晶型;能够提高聚合物基体的熔体黏度,减小泡孔尺寸,增加泡孔密度,促使泡孔尺寸分布更均匀,最终能够形成泡孔密度为1.0×10~9个/cm~3、平均泡孔半径为16.4μm、发泡倍率为18倍、表观密度约为0.055g/cm~3的微孔发泡木粉/聚丙烯复合材料。

Influence of talc on crystallization behavior and cellular structure of microcellular foamed wood flour/PP composites

The microcellular foamed wood flour/polypropylene composites were prepared by a microcellular batch foaming process using talc as the nucleating agent and supercritical CO2 fluid as foaming agent.The crystallization behavior and microcellular structure of impact fractured of microcellular foamed composite were investigated by differential scanning calorimeter (DSC),X-ray diffractometer (XRD) and scanning electron microscopy (SEM).The results indicate that talc increases the crystallization rate and temperature of microcellular foamed wood flour/poly-propylene composites and induces imperfect α crystal.The addition of talc improves the melt viscosity of the polymer matrix.The talc also decreases the size of the cellular,inhibit the formation of big cellular,cellular coalescence and collapse.The cellular density of wood flour/polypropylene composites can be up to 1.0× 109/cm3,the average radius is 16.4 μm,and the expansion ratio can reach 18,the apparent density is 0.055 g/cm3.