The effect of γ-Irradiation and reactive extrusion on the structure and properties of polycarbonate and starch blends: A work oriented to the recycling of thermoplastic wastes

摘要

Polymer materials with improved properties can be obtained through polymer blends. As a polymer mixture is generally immiscible and incompatible, it is necessary to develop new methods to improve the interfacial adhesion. In this study, polycarbonate-based extruded thermoplastic were developed by blending polycarbonate with thermoplastic starch using extensive process engineering based on structure-property correlations. Starch was destructurized and plasticized followed by melt-blending with polycarbonate. The optimal conditions for processing of the thermoplastics blends were found to be 230°C, 2 min of processing time, and 3-6 wt % of glycerol. The effect of γ-irradiation on the fabrication of the blend was studied. Changes in structure, morphology, and properties resulting from γ-exposure in the range 0-150 kGy were investigated. Electron spin resonance results revealed that numerous radicals remained trapped in the materials after irradiation even after a long time enabling reactions between starch and polycarbonate. Results obtained from tensile test, differential scanning calorimetry, and dynamic mechanical analysis revealed the relatively good affinity between the two components after blending in a micro-extruder. Irradiated blends are thermally more stable than those non-irradiated. Mechanical tests also showed that the efficiency of the irradiation depended greatly on the dose applied to the initial materials.