An investigation into the relationship between the impact performance of rotationally molded polyethylene products and their dynamic mechanical properties

摘要

In this paper,a study of the relationship between the impact performance of rotationally molder polyethylenes and their dynamic mechanical properties is carrid out. A wide range of conventional liner low density polyethylene powders and metallocene catalyzed linear low density polyethylene powders were rotationally molded and tested. Instrumented falling weight impact tests were carried out over a temperature range of -60degC to 20degC. Dynamic Mechanical Thermal Anlaysis (DMTA)tests were also carrie dout between -100degC ad 90degC,at a frequency of 100Hz. Comparisons between the impact performance of metallocene catalyzed LLDPEs and Ziegler-Natta LLDPEs are made. The transitions evidnet in the DMTA rsults are related to changes in impact performance with temperature. The beta transition is found to fall in the tansition region between high impact performance at low temperatures and lower impact performance at ambient temperatures.