Maleic anhydride‐grafted linear low‐density polyethylene with low gel content

Abstract Maleic‐anhydride‐grafted linear low‐density polyethylene (LLDPE‐g‐MAH) with low gel content was synthesized by the solid‐phase grafting polymerization of low molecular weight linear low‐density polyethylene (LLDPE) with melt flow index of 49.4 g/10 min, its structure and properties were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, wide‐angle X‐ray diffraction, polarized optical microscopy, and capillary rheometer. At the experimental conditions, maleic anhydride is successfully grafted onto LLDPE with the grafting degree of 1.1–2.4% and the gel content less than 3.7% since the chain‐branching reaction is dominant side reaction. The melting temperature of LLDPE‐g‐MAH is higher than that of pristine LLDPE due to the increased molecular polarity, but its degree of crystallinity and crystallization rate decrease due to its chain‐branching structure. The apparent viscosity of LLDPE‐g‐MAH is higher than that of pristine LLDPE, and its shear‐sensitivity is weakened due to the chain branching and subsequent difficulty in disentanglement under shear force. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers