The mechanical properties of recyclable cable insulation materials based on thermo-plastic polyolefin blends

Since 1960s cross-linked polyethylene (XLPE) has become one of the most important insulation materials for extruded cables based on its excellent comprehensive performances including electrical, mechanical and thermal properties. However, the disadvantages of high level energy consuming in manufacturing process and hard to recycle at the end of lifetime have been non-negligible economic and environmental problems. Therefore, developing new insulation materials which are recyclable and low energy consuming is imperative. In this work, we study the mechanical properties of the binary blend system which contains high density polyethylene (HDPE) and linear low density polyethylene (LLDPE). The samples with different proportions are blended with rheometer and shaped in the specific moulds with press vulcanizer. The large-stress properties have been characterized by tensile tests and cantilever beam impact tests. The results show that the 70wt%LLDPE-30wt%HDPE blend exhibits the optimal mechanical properties with relatively high mechanical strength of 31MPa in tensile strength and 829% in breaking elongation (higher than XLPE) and low modulus of 450MPa (higher than XLPE) in blending system. Furthermore, the small-stress property of 70wt% LLDPE-30wt% HDPE blend is measured by dynamic thermo-mechanical analysis (DMA). In addition, the creep property of 70wt% LLDPE-30wt% HDPE blend is even better than XLPE below 130?. Therefore such a blend exhibits good mechanical behaviors and may find its potential application as an insulation material.