Toward Reactive Processing of Polyamide 6 Based Blends with Polyethylene Grafted with Maleic Anhydride and Acrylic Acid: Effect of Functionalization Degree

The reactivity of different polyethylene modifiers based on acrylic acid (AA) and maleic anhydride (MA) with polyamide 6 (PA6) is investigated, using several degrees of functionalization. The polymer blends are processed in an internal mixer and injection molded. Mechanical, rheological, infrared spectroscopy, thermal, thermomechanical properties, and morphology are evaluated. The torque rheometry results show that higher functionalization degrees favored a high reactivity with PA6. As a consequence, there is an increase in the viscosity of the polymer blends, which is reflected in the reduction of the melt flow index (MFI), compared to PA6. High impact strength and elongation at break properties confirm the blends' compatibility. The elastic modulus and the tensile strength maintain high values, suggesting a balance of mechanical properties. In addition, the polymer blends' heat deflection temperature (HDT) and thermal stability properties are comparable to neat PA6. The morphology obtained by scanning electron microscopy show dispersed and refined particles in the PA6 matrix, indicating stabilization at the interface. Incorporating only 10% of high-density polyethylene grafted with acrylic-acid (HDPE-g-AA) is very efficient in optimizing the properties of PA6, contributing to broadening the range of applications for the processing industry.