Improvement of compatibility in glass-reinforced PA6/PP blends

This article deals with the study of the properties of glass-reinforced (30% in weight) compatibilized blends of polypropylene (PP) and polyamide (PA6). Reological properties (melt flow index and melt stability) and mechanical properties (tensile strength, flexural strength, and impact) of PA6/PP blends were investigated. The influence of potential compatibilizators 4,4'-diphenylmethane carbodiimide (OCDI), 4,4'-diphenylmethane bismaleimide (BMI), and 2,2'-(1,4-phenylene)-bisoxazoline (BOX) on mechanical properties and thermostability of initial and glass-reinforced polymer blends was investigated too. We tried to study the structure of glass-reinforced composites by mercury-intrusion porosimetry. The influence of compatibilizators on the molecular weight of PA6 was studied by gel permeation chromatography; that on the chemical structure of blends was investigated by nuclear magnetic resonance and infrared spectroscopy. The addition of OCDI and BOX (chain extenders) preserves the product formation as they react with the active and carbonyl groups of PA6. BMI has lower reactivity. Grafting of BMI to PP chains improves compatibility in the PA6/PP blend and increases PP adhesion to glass fiber.