Modification of Low Density Polyethylene with 2-Hydroxyethyl Acrylate by a Swollen-Phase Grafting Method

Abstract

ABSTRACTLow-density polyethylene (LDPE) was modified with 2-hydroxyethyl acrylate (HEA) by a swollen phase grafting method with azobisiso-butyronitrile (AIBN) as initiator and xylene as a swelling agent. Fourier transform infrared spectroscopy (FTIR) and 1H-nuclear magnetic resonance (1H-NMR) showed that the HEA was grafted onto the PE molecular chains and the copolymer (LDPE-g-PHEA) was formed. The rheological data illustrated that the content of long chain branches (LCB) in LDPE-g-PHEA was higher than in LDPE. Melt flow index (MFI) measurements indicated that the LDPE backbone was degraded slightly when the HEA content was small in the process of grafting. X-ray diffraction (XRD) and water contact angle measurements demo-nstrated that the grafting degree had an influence on the crystallinity and polarity of the graft polymer. A staining analysis indicated that the dyeing of the product was improved continuously with increasing of the grafting degree. Polyvinylpyrrolidone (PVP), NaCl, and ultrasound were shown to contribute to the staining, with ultrasound being the most productive. The probable grafting reaction mechanism is pro-posed. The results of the influence of monomer concentration on the grafting reaction revealed that the grafting ratio and gel content of the product increased with increasing of HEA amount.