Reactive melt blending of low-density polyethylene with poly (acrylic acid)

Reactive melt blending of low-density polyethylene LDPE with a low molecular weight poly (acrylic acid) PAA in the presence of benzoyl peroxide (BPO) free radical initiator was studied by means of a HAAKE torque rheometer and a capillary rheometer FTIR spectroscopy and was used to characterize the structure of LDPE/PAA blends. The rheological behavior of blends has been investigated at different temperatures (170, 190, 210 and 230 °C) and shear rates (5.43, 18.1, 54.3, 181 and 543 S−1). With a rise of temperature and increasing shear rates the shear stress of blends increases nonlinearly. The melt viscosity increases with the increase in the PAA proportion but decreases with the increasing shear rate and shear stress. The melts of all the blends are pseudoplastic in nature. The flow behavior index (n) of the blends decreases with the increase in the PAA proportion and with the increase in the temperature. The temperature sensitivity of the flow behavior of the blends is studied using Arrhenius plots. The system exhibits relatively low activation energy which means less sensitivity to temperature with an increase in the PAA ratio.