Plastic is a synthetic polymer that is difficult to decompose in nature, taking hundreds of years to decompose. The increase in plastic use is inversely proportional to the time it takes to decompose, so the impact of the accumulation of plastic waste on the environment is very serious. This research analyzes the hardness and microstructure of HDPE, PP and coconut fiber plastic waste with temperature variations. This research aims to determine the hardness test value, as well as the micro and macro structural characteristics of the material being tested. Testing was carried out using the Rockwell method. The results of the research showed that the highest results for 100% HDPE hardness testing were at a temperature of 280°C with HRB 90. The highest results for 100% PP plastic at a temperature of 280°C were HRB 88.3 and the highest results for a mixture of 60% HDPE : 20% PP : 20% coconut fiber at temperature 280°C with HRB 59.6. The results of the research showed that the lowest result of 100% HDPE hardness testing was at a temperature of 240°C with HRB 62. The lowest result for 100% PP plastic at a temperature of 240°C was HRB 66.3 and the lowest result was a mixture of 60% HDPE : 20% PP : 20% coconut fiber at a temperature of 240°C with an HRB of 46. By making composites made from HDPE, PP and coconut fiber plastic, plastic waste can be reduced.
Keywords: Plastic Waste, Hardness, Temperature Variations.