纳米纤维用PP/CAB共混母粒中分散相尺寸的影响因素研究

Affect Factors of Dispersed Phase Size in PP/CAB Blends for Preparing Nanofibers

利用相分离的方法制备热塑性聚丙烯(PP)纳米纤维,将不相容的PP和醋酸丁酸纤维素(CAB)两种聚合物在双螺杆挤出机中共混,制备出合适的母粒用于熔融静电纺丝。通过不同条件下的实验,研究了影响PP分散相粒子尺寸大小的因素,利用扫描电子显微镜观察了共混物的形态,并通过旋转流变仪测量了共混物在不同温度和不同剪切速率下的流变行为。结果表明,PP含量和熔融温度对分散相粒子尺寸的影响最为显著,其次为共混时间,螺杆转速的影响最小;当PP质量分数为20%,熔融温度为210℃,螺杆转速为25 r/min,共混时间为4 min时,可得到尺寸较小的PP分散相粒子。将上述条件下制备的母粒通过熔融静电纺丝技术制备PP/CAB纤维,经丙酮处理除去CAB,得到的PP纳米纤维的平均直径为320 nm左右,与直接熔融静电纺丝制备的PP纤维(平均直径为3.5μm左右)相比,纤维的直径降低了一个数量级,使得纤维细化。

Thermoplastic polypropylene（PP） nanofibers was produced by utilizing phase separation method, PP and cellulose acetate butyrate （CAB） immiscible blends were prepared in a twin-screw extruder for melt-electrospinning. The factors which could affect the size of dispersed PP phase in the blends were studied under different conditions. The morphology of the blends was observed by SEM and the rheological behaviors of the blends were measured by rotary rheometer under different temperature and shear rate. The results show that the effects of PP content and melting temperature on the dispersed phase size are most significant , followed by blending time, the effect of the screw rotating speed is minimal. When the mass fraction of PP is 20%, melting temperature is 210%, screw rotating speed is 25 r/min, blending time is four minutes, the dispersed PP phase with smaller size can be obtained. PP/CAB fibers were manufactured by melt-electrospinning through using the PP/CAB blends by the conditions mentioned above, after removing CAB by acetone, the PP nanofibers with average diameter being about 320 nm were got. Compared with direct melt-electrospinning fibers （about 3.5μm）, the diameter of the nanofiber is reduced by an order of magnitude, which makes the fiber fine.