Strength of thermoplastic elastomers from rubber-polyolefin blends

The strength of different thermoplastic elastomers of varying compositions and interactions has been examined over a wide range of rates and temperatures and for a wide variety of test configurations. Fracture energy was calculated from various test specimens and found to be similar, and independent of the test configuration. Fracture energy values lie between 0.8 and 120kJm_–2. The behaviour could be compared with that of rubbers. However, for a trouser-tear test piece, the fracture energy increases with increasing thickness of the torn path in the very small thickness region, as for the fracture of polyethylene. The fracture surface morphology of various composites indicates different mechanisms of crack propagation. The tensile rupture data over a wide range of rates and temperatures could be represented by a single parabolic curve — the failure envelope. The maximum elongation at break and tensile strength of the composites are related to the modulus.