Relationship between the structure and mechanical properties of polypropylene: Effects of the molecular weight and shear‐induced structure

摘要: A series of homopolymer polypropylenes (PPs), within a weight-average molecular weight (Mw) range 100-1600 kg/mol, were manufactured as dumbbell microspecimens. The effects the and shear-induced crystallization on mechanical properties morphology studied to gain better understanding structure-property relationship. results showed that crystallinity decreased from 50 41% lamellar thickness increased Mw increased. Tensile tests demonstrated stiffness especially tensile strength rose extremely high values (Young's modulus = 2400 N/mm2, stress at 30% strain 120 N/mm2). Furthermore, hardening effect was strongly affected by highly oriented superstructures. Dynamic analysis mobility chains depended thickness. In addition, viscoelastic unannealed annealed samples indicated further existence shish-kebab structures caused during injection molding.