双辊混炼实现低缠结超高分子量聚乙烯熔融加工及高性能化

Melt Processing and Performance-enhanced of Ultra High Molecular Weight Polyethylene via Calendar Rolling

以低缠结超高分子量聚乙烯(dis-UHMWPE)和常规高度缠结超高分子量聚乙烯(c-UHMWPE)为原料,利用双辊混炼提供的复合力场,实现了纯超高分子量聚乙烯(UHMWPE)的熔融加工,并制备了高性能的UHMWPE片材。力学性能测试表明,dis-UHMWPE力学强度由模压成型的56 MPa提高到了159 MPa,断裂伸长率为247%,综合性能优异。而c-UHMWPE力学强度无明显变化。差示扫描量热法(DSC)、X射线广角衍射(WAXD)、X射线小角散射(SAXS)和密度测试表明,在经过双辊混炼之后,dis-UHMWPE和c-UHMWPE片材的结晶度、取向度和密度无明显差别。而扫描电镜(SEM)表明dis-UHMWPE在双辊混炼后缺陷较少,形成结构均一的制品,而c-UHMWPE存在较多缺陷。因此,UHMWPE加工制品内部的结构均匀性是决定力学性能的关键因素。为制备高性能的UHMWPE片材提供了新思路。

Taking disentangled ultra-high molecular weight polyethylene(dis-UHMWPE)and commercial ultra-high molecular weight polyethylene(c-UHMWPE)as raw material,high performance ultra-high molecular weight polyethylene(UHMWPE)tapes was prepared by the double roller mixing compound force field.The mechanical properties tests show that the mechanical strength of dis-UHMWPE could increase from 56 MPa to 159 MPa and elongation at break is 247%.However,the mechanical strength of c-UHMWPE does not increase significantly.Differential scanning calorimetry(DSC),X-ray wide-angle diffraction(WAXD),X-ray small-angle scattering(SAXS)and density test show that the crystallinity,orientation and density of tapes could not change significantly after calendar rolling.Scanning electron microscopy(SEM)shows that dis-UHMWPE has fewer defects after calendar rolling and forms a uniform structure.c-UHMWPE has many defects.Therefore,the internal structure uniformity of UHMWPE processed products is the key factor to determine the mechanical properties.This provides a new strategy for the preparation of high-performance UHMWPE tapes.