Electron-Microscopy Investigations of the Warping Effect in Pigmented High Density Polyethylene

Abstract

The warping effect of high-density polyethylene (HDPE) articles produced by organic pigmentation has been studied by scanning electron microscopy. A warping pigment and its warp-free analogue obtained by surface treatment have been observed and compared to an inorganic warp-free pigment. The results indicate that the generally accepted nucleation theory is not sufficient to describe fully the warping effect. An attempt is made to describe this effect in terms of pigment-polymer compatibility.