Mechanical properties of polyethylene mixtures crystallized under high pressure

摘要

The mechanical properties of a medium molecular weight polyethylene (MMW-PE) and an ultrahigh molecular weight PE (UHMW-PE) binary mixture with different weight fractions crystallized from the melt at 0.1 and 450 MPa were studied. The tensile modulus, yield stress, and strain were obtained as a function of the weight fractions in the PE mixtures at 25 and 85degreesC. The tensile modulus in the sample crystallized at 0.1 MPa decreased from 1.5 GPa of pure MMW-PE to about 0.4 GPa of pure UHMW-PE with the UHMW-PE content but it did not decrease with the UHMW-PE in the sample crystallized at 450 MPa in testing at 25degreesC. A decreasing rate of the storage modulus E' of UHMW-PE in a dynamic measurement for the sample crystallized at 0.1 MPa with the temperature is larger than that of the sample crystallized at 450 MPa. These experimental facts are interpreted in relation to the molecular motion and crystallinity of the sample. (C) 2003 Wiley Periodicals, Inc. [References: 22]