Birefringence Distribution in Gas Assisted Tubular Injection Moldings
Average birefringence and radial distribution of birefringence ?n and n??-nrr in polystyrene spiral tubular articles prepared by gas assisted injection molding were measured. The molded articles were obtained under various processing conditions. The results show that the birefringence ?n attains a maximum value near the outer wall in both the sprue and tubular molding. This maximum value decreases along the sprue length, is almost constant in the region of primary gas penetration and decays significantly in the region where the gas did not penetrate. The effect of flow rate, gas pressure, shot size, melt temperature and gas delay time was elucidated.
Isayev, Avraam, "Birefringence Distribution in Gas Assisted Tubular Injection Moldings" (2006). Polymer Engineering Faculty Research. 136.