Crystallization, structure, and properties of polypropylene random copolymer (PPR) / high-density polyethylene/polypropylene grafted maleic anhydride((HDPE/PP)-g-MAH) blends

Polypropylene/Polyethylene (PP/PE) incompatibility is the key factor that restricts the use of PE to further improve the performance of Polypropylene Random (PPR). Although there are many studies on PP/PE blends have been compatibilized by adding Maleic Anhydride (MAH) as a solubilizer, how MAH affects the crystal structure of PPR/PE blends has not been systematically investigated. This study compares the thermodynamic and crystallization behavior that adding of PPR and PPR blended with MAH-grafted PP and High-density polyethylene (HDPE). The addition of a small amount of (EP1:1)-MAH (MAH grafted PP/HDPE 1:1 blend) considerably enhanced the crystallization temperature of the system. Small-Angle X-ray Scattering (SAXS) confirmed that (EP1:1)-MAH has reduced the order of the lamellae structure of the PPR blend system compared with the addition of EP1:1 (ungrafted PP/PE 1:1 blend). MAH-grafted PE (PE-g-MAH) and MAH-grafted PP (PP-g-MAH) are compatible with PPR, thus allowing easy entry of PE into the phase region of PP and vice versa. By clarifying the crystal structure modification of PE/PPR blends, this study highlights the application potential of modifying PPR with the MAH-grafted polymer.