干燥法制备聚丙烯腈初生纤维样品的研究

Study on the preparation of PAN nascent fibers specimen by drying

采用湿法纺丝得到聚丙烯腈(PAN)初生纤维,干燥后得到PAN初生纤维样品。利用电阻法确定初生纤维的共晶温度;获得初生纤维的冻干曲线;通过压汞法对初生纤维孔结构进行表征,并对比考察了鼓风干燥、自然风干和冷冻干燥对样品截面形貌的影响。结果表明:初生纤维的共晶温度为-55℃;鼓风干燥会使样品收缩,纤维间发生粘连,原有形貌被破坏;自然风干使样品的截面积和周长分别收缩了20.66%、10.67%,形状系数变化率为3.52%。而冷冻干燥时样品的截面积和周长仅收缩了1.21%、1.15%,形状系数变化率为1.13%。冷冻干燥有效地保留了PAN初生纤维的固有原始结构,可用于制备各种分析的样品。

The sample of PAN nascent fibers was prepared by wet-spinning and drying technology. The co-crystal temperature of PAN nascent fibers was measured by electri-resistivity method. The freeze drying curve was obtained, The pore structure of PAN nascent fibers was measured by mercury porosimetry and the effect of air drying, natural drying and freeze drying on the section pattern of PAN nascent fibers was discussed. The results indicate that the co-crystal temperature of PAN nascent fibers specimen was -55℃. Air dried samples had shrinkage and became bound together because of adhesion. The inherent structure of PAN nascent fibers was destroyed. The sectional area, perimeter and shape coefficient were reduced by 20.66, 10. 67 and 3.52 percent during natural drying, respectively, while reduced by 1. 21, 1.15 and 1.13 percent during freeze drying. The inherent structure of PAN nascent fibers was preserved during freeze drying. It was prepared for PAN nascent fibers specimen by freeze-drying technology.