以旋转竖直铜针为收集器静电纺制备PVP螺旋型纤维绳

PREPARATION OF PVP HELICAL FIBER BY ELECTROSPINNING WITH SINGLE COLLECTION UPRIGHT COPPER NEEDLE

以竖直旋转的细铜针为接收器,聚乙烯基吡咯烷酮(PVP)/无水乙醇质量分数为10%,电压25 kV,在不同的旋转速度下纺出了PVP螺旋纤维绳.当竖直细铜针固定不转时,纺丝纤维呈松散线状结构;竖直细铜针旋转速度加快,纤维形态由松散的螺旋缠绕向紧密缠绕的趋势变化,PVP纤维在纺丝针头和接收铜丝间静电库仑引力(垂直方向),纺出纤维间的库仑斥力(水平方向),以及铜针高速旋转力(切线方向)的三重作用下,最终制得PVP螺旋微米纤维绳.用扫描电子显微镜(SEM)对其进行表征.实验结果表明,接收器旋转速度和接收距离对多螺旋结构纤维的形貌有显著影响.讨论了螺旋纤维的形成机理.

A convenient method was developed to fabricated helical nano-fiber yarn in one step and with high efficiency. Poly（vinyl pyrrolidone） （PVP） sol （M, = 1.3 × 10^6, 10% in ethanol） was electrospun at the voltage of 25 kV,using a thin upright copper needle as a collector with the rotation speed of 0 - 1200 r/min. In this setup, centimeters-long precursor fibers are spontaneously electrospun on the tip of the upright needle target parallel to the electric field. The electrospinning process is mainly controlled by the electrostatic forces. Thus, when a grounded needle is close to the splaying jet, the splaying jet will be converged and then deposed on the needle. The yarn was formed between the needle and the spinneret, and the jet will be folded and aligned to form a self-bundling yarn. The morphologies of helical fiber were observed by scanning electron microscopy （SEM） . The morphologies of PVP fibers were changed from non-helical, dispersed-helical to tight-helical fibers forming a multi-filament yarn in the various rotating speeds. The Coulomb attracting force （in the vertical direction due to the static fields between the jet and the copper thread）, the Coulomb excluding force between the spinning fibers （in the horizontal direction） and the shear force （in the tangential direction due to the high rotation speed by copper needle） are the three main factors to form the helical fibers. The main advantages of producing PVP fiber yarns by this technique are the minimum polymer degradation and forming the multi-filament yarns having a high tenacity.