An evaluation of polypropylene by dynamic mechanical tests

Abstract The loss factor ratio is dependent upon temperature and the rate of change of mechanical load or frequency of the oscillatory loading. The limit of linear viscoelastic response is another variable which occurs at the break in the stress‐strain curve. If storage modulus varies slightly, with magnitude of stress or strain, the data is considered linear viscoelastic. The only true test is in the limit of zero strain and independent modulus. Polypropylene's dynamic properties are most dependent on test temperature. The loss factor peak which can be controlled by temperature and pressure history during crystallization is an indication of the ductile‐brittle transition point.