Nanoclay assisted ultra-drawing of polypropylene tapes

Abstract

Isotactic polypropylene (i-PP)–montmorillonite (MMT) nanocomposite films were prepared by melt-compounding and hot-pressing. The influence of organoclays on the mechanical properties and drawability of these isotropic composite films was investigated. Ultimate properties of solid-state drawn PP tapes incorporating 2.5 wt% MMT outperformed those of pure PP tapes. Interestingly, these improvements were found not to be the result of a mechanical reinforcement effect of the nanoclay platelets but merely the result of a more efficient ultra-drawing mechanism with MMT acting as a processing additive that altered initial polymer morphology and drawing behaviour. Hence, the introduction of MMT resulted in higher ultimate draw ratios and subsequently higher ultimate mechanical properties of the oriented nanocomposite tapes.