Abstract:
Applying thermal insulation material in the wall is a major means of improving building energy
conservation. However, traditional building insulation materials have defects in varying
degrees, including, water absorption, low strength and not environment-friendly. To solve this
problem, a novel thermal insulation bio-composite composed of spent brewery diatomite earth,
sawdust and HDPE waste plastic-based composite materials were manufactured by the melt mixing method followed by compression molding. The effect of HDPE, DE and, SW weight
proportion and mold compression load (CL) on composite properties were investigated to
evaluate their physical (water absorption, density, morphological properties), thermal (thermal
conductivity, thermal diffusivity, specific heat capacity and thermal stability) and mechanical
(compressive and flexural strength) tests. A D-optimality design was employed to determine the
optimum preparation condition of the thermal insulation bio-composites, to obtain the lowest
thermal conductivity and water absorption value and the highest compressive strength. It was
found that composites were best fit by a linear * quadratic regression model with high coefficient
of determination (R2
) value (0.9995, 0.9988, and 0.9998) for WA, CS, and TC respectively. The
selected optimum condition was 72.13 wt.% HDPE, 25wt.% DE, 2.87 wt.% SW, and 10 MPa
mold compression load (CL), leading to a desirability of 75.6 %. Under the optimum condition,
the thermal conductivity, water absorption, and compressive strength of the bio-composites were
0.023 W/(m.k), 0.603 %, and 87.579 MPa, respectively. Those selected optimum parameter
formulation was also gave the maximum flexural strength ~94.2 MPa. The thermal conductivity,
thermal diffusivity and bulk density of the samples decreased as filler (DE/SW) contents were
increased and mold compression load (CL) decreased. In addition, the thermal stability of the
samples increase with DE weight proportion and mold compression load (CL). The compressive
and flexural strength of the TIDSPCs were higher than those the commonly used insulating
materials and comparable to those of construction materials (52.47 - 87.579 MPa) and (50.8 -
94.2 MPa), respectively. The characteristic of the TIDSPCs indicate that they are stable
composites with promising insulation and construction capacity. The developed materials may
be used in the handle of kitchen utensils and other materials that required thermal insulation.
