Characterization of polypropylene/poly(2,6-dimethyl-1,4-phenylene oxide) blends with improved thermal stability

In this article, the morphological, mechanical and thermal properties of melt blended of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polypropylene (PP) have been studied. The solubility parameters for the molecular structure of the PP and PPO polymers were calculated using the Hoftyzer-Van k. and Hoy methods. The theoretical calculations reveal that the blend of PP and PPO polymers is immiscible. The miscibility of the PP/PPO blends containing different weight content of PPO (ranging from 5 to 20 wt%) was also evaluated by the scanning electron microscopy. The matrix-dispersed particle structure of the PP/PPO blends confirms the immiscibility of the blends. The flexural stress-strain curves were plotted for the PP and PP/PPO blends. A further improvement has appeared in the values of the bending modulus and strength of the blends comparing with that of the neat PP. The crystallization and melting temperatures of the PP/PPO blend have been evaluated using differential scanning calorimetry. The crystallization temperatures of the PP/PPO blend were shifted toward higher values with the addition of the PPO. One can see that the PPO affected the crystallinity behavior of the PP. Moreover, a significant reduction in thermal degradation rate of the PP/PPO blend was observed with the addition of PPO polymer into the host PP matrix.