Crystallization behavior of hyperbranched polyethylenes with different degree of branching

Hyperbranched polyethylenes (HBPEs) with different degree of branching (DB) and similar M-n are used to investigate the effect of branch structure on their crystallization behaviors. The crystal structure, isothermal, and non-isothermal crystallization kinetics of HBPEs are studied by X-ray diffraction and differential scanning calorimetry. The isothermal crystallization process is analyzed by the Avrami equation while the non-isothermal crystallization process is analyzed through the Ozawa and Mo methods. The XRD results indicate that the crystallization ability of HBPEs is weakened with the introduction of branch structure, i.e., the crystallinity of HBPEs decreases with the increase of DB, and even tends to zero. The kinetics results of isothermal and non-isothermal crystallization verify the peculiar effects of DB on the crystallization process of HBPEs. In detail, a little of branch structure can accelerate the crystallization process of HBPEs, however a large number of branch can inhibit it. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44127.