Effect of Reaction Temperature on HDPE Functionalized Through Ultraviolet Irradiation

Abstract

Some oxygen-containing groups such as C˭O, C‒O and C(˭O)O were introduced onto the molecular chains of high-density polyethylene (HDPE) through ultraviolet irradiation at different environmental temperatures in air. The functionalization rate of HDPE was accelerated with increasing environmental temperature. After ultraviolet irradiation, the molecular weight, melting temperature, and water contact angle of HDPE decreased, whereas the degree of crystallinity increased, and their change increased with environmental temperature at the same irradiation time. The crystal shape of irradiated HDPE remained unchanged in an orthorthombic structure. The HDPE irradiated for 24 h at environmental temperature of 50°C was not crosslinked. However, gelation took place in the HDPE irradiated for 24 h at environmental temperature of 70°C and 90°C, and the gel content increased with increasing environmental temperature, The compatibilization of the functionalized HDPE in HDPE/PVA composites increased with environmental temperature under the same irradiation time.