高强度聚偏氟乙烯纤维的熔融纺丝法制备

为得到高拉伸强度的聚偏氟乙烯(PVDF)纤维，通过正交实验和单因素实验，研究了熔融纺丝法制备PVDF纤维的工艺条件，并利用热分析(DSC)、红外光谱法(FT-IR)、X射线衍射(XRD)和拉伸试验研究了纤维的晶体结构、晶区取向和力学性能。研究结果表明：纺丝过程中影响纤维拉伸强度的因素主次顺序为卷绕速率>喷头温度>喷嘴直径>入水距离，最优条件为卷绕速率10.2 m/min，喷头温度240 °C，喷嘴直径2.0 mm，入水距离40 cm；初生纤维既含有α晶型，也有β晶型，冷拉伸使得纤维发生α→β晶型转变，总体结晶度和取向度均有提高，拉伸强度明显提高，并在最大拉伸倍数6.5倍左右达到最大值591 MPa。

Melt spinning of poly(vinylidene fluoride) fibers with high strength

In order to obtain poly(vinylidene fluoride) (PVDF) fibers with high tensile strength, orthogonal test and single factor test were designed to explore the best process parameters of melt spinning of PVDF fibers. Thermal analysis (DSC) , infrared spectrum (FTIR), X- ray diffraction (XRD), and tensile test were carried out toanalyze the crystalline structure, crystal orientation and mechanical properties of the fibers. The results showed that: the important order of relevant factors on tensile strength was: winding speed > spineret temperature > spineret size > air gap, optimal winding speed was 10.2 m/min, optimal spineret temperature was 240 °C, optimal spineret size was 2.0 mm, optimal air gap was 40 cm;α-phase crystalline andβ-phase crystalline was co-exist in as-spun fibers; by cold drawing,α-phase crystalline could be transformed into theβ-phase, the crystallinity and orientation tactor were increased with the increase of draw ratio, which was hilpful to the improvement of mechanical properties, and the tensile strength reached 591 MPa when cold drawing ratio was 6.5.