Thermal and mechanical properties of extruded LLDPE/wax blends

The thermal and mechanical properties of linear low-density polyethylene (LLDPE)/wax blends, prepared in an extruder, were investigated, using differential scanning calorimetry (DSC) and tensile testing. DSC measurements indicated that blends consisting of 10 and 20% of wax are probably miscible in the crystalline phase. For 30% and more wax, phase separation of the two components were observed. The DSC curves of both pure LLDPE and blends show, beside the main exothermic peak, another small peak at about 70 degreesC. Since this peak was observed for both pure LLDPE and the blends, it is probable that its origin is partly in the LLDPE structure, but it is also influenced by wax crystallization. An increase in Young's modulus with an increase in wax content was observed. An increase in wax content causes a decrease in elongation at yield. A small increase in yield stress was observed for blends consisting of 10 and 20% of wax. For blends consisting of 30% and more wax, no yield point, but brittle rupture, was observed. (C) 2001 Elsevier Science Ltd. All rights reserved.