Manufacturing Polyurethane Slag from Composite using Polyol from Polyethylene Plastic Waste

This research aims to develop polyurethane foam using recycled PET (Polyethylene Terephthalate) and HDPE (High-Density Polyethylene) plastic bottles as substitutes for polyol. Waste PET bottles were recycled through a glycolysis process to produce BHET (bis(hydroxyethyl) terephthalate), utilized as a polyol substitute in polyurethane foam production. The foam was synthesized by reacting polyol with Methylene Diphenyl Diisocyanate (MDI), with variations in the composition of distilled water as a blowing agent, silicone as a surfactant, and steel slag (10%, 10%, 10%, and 60%) to enhance mechanical properties. Four polyurethane foam samples were tested, resulting in rigid, flexible, and semi-rigid foams, depending on the formulation. Sample 1 demonstrated a compressive strength of 0.225 MPa, Young's modulus of 0.0139 MPa, yield strength of 0.174 MPa, and density of 0.11 g/cm³. Sample 2 exhibited a compressive strength of 0.18 MPa, Young's modulus of 0.0109 MPa, yield strength of 0.117 MPa, and density of 0.06 g/cm³. Sample 3 had the lowest compressive strength (0.02 MPa), Young's modulus (0.00079 MPa), yield strength (0.0092 MPa), and density (0.09 g/cm³). Sample 4 recorded a compressive strength of 0.12 MPa, Young's modulus of 0.0116 MPa, yield strength of 0.0901 MPa, and density of 0.04 g/cm³. Sample 1 exhibited the highest mechanical performance, while Sample 3 showed the lowest. These results indicate that polyurethane foam with optimal compressive strength, Young's modulus, yield strength, density, and flexibility can be produced, meeting the requirements of SNI (Standar Nasional Indonesia) Standard 0111-2009 for shoe applications.