New char-based insulation foam by mechanical mixing method and the impact of ingredient contents on its properties

Developing new technologies and innovative materials for alternative usage of coal are highly demanding for supporting the coal industry. The development of high-value eco-friendly building materials from coal-derived products has the potential to contribute to this purpose. This paper presents the development of a new char-based insulation foam (CIF) incorporating coal-derived byproduct pyrolysis char (PC) and pulp industry byproduct lignin. The CIF is produced by adopting the mixing method through manual stirring and mechanical stirring at different stages of the fabrication process. The investigation focuses on optimizing the recipe for the CIF by exploring different ingredient compositions, including PC, lignin, solvents, and foaming agents. The goal is to achieve lower thermal conductivity and density while increasing the foaming ratio and compressive strength of the CIF. The measured thermal conductivity, compressive strength, foaming ratio, and bulk density of CIF with 10 % PC are about 0.06 W/m.K, 1200 kPa, 4.2 and 170 kg/m3, respectively. These properties of CIF are comparable to or better than the other traditional building insulation products such as Polyurethane, fiber insulation, particle board, polymer composite, and ceramic glass foam. The characterization analyses show that the CIF exhibits higher thermal stability, indicating higher fire resistance than that of a pure polyurethane foam. This CIF has the potential to be used as a building insulation material for the building facade to improve energy efficiency.