Study on properties of rigid polyurethane foam as a thermal building insulator at varied mixing conditions

The concept of zero-energy building is one of the promising ways to improve energy efficiency, resulting in the reduction of greenhouse gas emissions. The use of rigid polyurethane foam (RPUF) has been widely used as insulation material in building panels because of its excellent properties including light-weight, durability, and lower thermal conductivity. This study aimed to determine the effect of mixing conditions on the production of RPUF at varied mixing speeds (300, 500, 1000 rpm) corresponding to its density, mechanical, and insulation properties. It was observed that the well-defined physical structure of RPUF was obtained at the minimum mixing speed of 500 rpm. The foam density changed with the increasing mixing speed, from 39.8 kg/m³ at 500 rpm to 51.30 kg/m³ at 1000 rpm. This might be because of the possible loss of the blowing agent due to excessive mixing speed as noted by the constrained foam expansion and the shorter time for the free-rise process. The thermal insulation property of obtained RPUF was significantly lower than that of conventional building materials like concrete. This research is one of the key technologies to reduce the energy consumption for heating-cooling buildings and thus create a potential strategy for climate change mitigation.