T. M. Malik, P. J. Carreau, H. P. Schreiber, A. Rudin, W. Tchir
May 27, 2013
The relationship between draw ability of high density polyethylene (HDPE) and entanglement density in the polymer has been studied by solution modifying the polymer. This involved precipitating the polyethylene from solutions in trichlorobenzene. Entanglement densities of solution modified and control (as received) HDPE were estimated from low-shear melt viscosity data. One and two stage drawing techniques at closely controlled temperatures were applied to form drawn film specimens. It was shown that solution modified versions of HDPE permitted drawing to much higher ratios than the control, and resulted in films with elastic moduli in the 40 GPa range. A relationship is thereby suggested linking polymer entanglement density with mechanical properties attained in the drawing process. Optimization of drawing performance appears to be attainable by controlling entanglement density, through appropriate choices of solvent and of initial polymer concentration in the solutions.