Valorizing mixed plastic wastes from cardboard recycling by amendment with wood, cement and ash

Abstract

This project sought improved mechanical strength and thermal properties of mixed plastic rejects from cardboard recycling. The Wandel screen, a process unit, captures 75% of a facility’s total plastic output and consists of hot melt (∼37%), polypropylene (∼32%), polyethylene (∼17%) and polystyrene (∼9%). The mixed plastic was compounded with wood flour, cement, ash and maleated polyethylene. Wood flour and maleated polyethylene increased the tensile modulus by 65%, ash and cement increased moduli by 49% and 39%. Maleated polyethylene decreased crystallinity and compatibilized both mixed polymers and additives. Samples were characterized by differential scanning calorimetry and thermal gravimetric analysis. Additives decreased phase separation. Thermal gravimetric analysis showed wood flour, ash, cement and maleated polyethylene thermally stabilized the plastics. These improvements make this mixed plastic waste more attractive for reuse.