“ Effect of Alkali Lignin on Heat of Fusion, Crystallinity and Melting Points of Low Density polyethylene(LDPE), Meduim Density polyethylene(MDPE) and High Density polyethylene(HDPE)”. 2010. University of Thi-Qar Journal of Science 2 (2): 89-95. http://jsci.utq.edu.iq/index.php/main/article/view/354.