A linear low-density polyethylene (LLDPE) with hexyl branches has been blended with high-density polyethylene (HDPE) and a comparison has been made of the effects of three methods of blending on the quality of the blends produced. A twin-screw extruder, roll mills and solution precipitation have been compared for their effectiveness in producing a uniform blend. Compositional variations have been measured by Fourier-transform infra-red spectroscopy, crystallization and melting characteristics have been studied using differential scanning calorimetry, and the morphology has been examined by wide-angle X-ray scattering and scanning electron microscopy. In general, it is concluded that in the melt the two grades of PE are compatible and co-crystallize on quenching. The most uniform product is produced by the twin-screw extruder, since the blends have higher melting points, crystallinity, yield stress and elongation at break. The solution-blended product crystallizes at a lower temperature than the others, consistent with a reduction in heterogeneous nucleation
Посилання на статтю:
The effect of mixing on the properties of polyethylene blends / J. N. Hay* and Xiao-Qi Zhou // Polymer. – 1993. – Vol 34. – P. 2282-2288.