A comparison of degree of properties enhancement produced by thermal annealing between polyethylene and calcium carbonate-polyethylene composites

The annealing of unfilled and filled composites was carried out to assess the effect on property changes in both types of materials. By employing DSC and tensile testing, it was found that increasing annealed temperature increases melting temperature, crystallinity, modulus and tensile strength, while yield strain remained constant throughout the test. The increase in thermal and mechanical properties was associated with the change in morphology and thickness of lamellae of polyethylene fraction in the materials. In general, the degree of change in properties was independent of filler content. However, the increase in tensile strength was found to depend upon filler incorporation. All compositions of filled polyethylene exhibited a similar degree of strength increase, but less than the increase seen in unfilled polyethylene. This is due to the premature failure of composites due to interfacial debonding in filled polyethylene. (C) 2000 Elsevier Science Ltd. All rights reserved.