Sustainable thermal insulation biocomposites from rice husk, wheat husk, wood fibers and textile waste fibers: Elaboration and performances evaluation

Building materials derived from agricultural and industrial waste are becoming more attractive in the civil engineering and architectural applications because of their sustainability and lower environmental impact. In addition, substantial value can be added to the wastes by producing value added products from them. Therefore, four different types of locally available by-products (rice husk, wheat husk, wood fibers and textile waste fibers) were used to produce composites with a biodegradable poly(butylene adipate-co-terephthalate)/poly(lactic acid) (PBAT/PLA) blend binder by hot pressing. The morphological analysis of the composites revealed that the PBAT/PLA binder had more affinity with wood and textile fibers than with wheat and rice husks. The prepared composites showed thermal stability until 250 °C. All the prepared biodegradable composites exhibited good compressive strength (11–40 MPa) and flexural strength (0.80–2.25 MPa). The observed mechanical properties allow easy handling without risk of breaking them when positioned in the buildings. The biodegradable composites were characterized for their thermal conductivity, diffusivity, effusivity and heat capacity. The density and thermal conductivity of the produced composite was in the range of 378–488 kg/m3 and 0.08-0.14 W/m.K, respectively. The least thermal conductivity i.e. 0.08 W/m.K was observed for the rice husk composite with a density of 378 kg/m3. A minimum water absorption (42%) was found in the rice husk composites after 24 h immersion in water. The composite samples were still cohesive after 24 h immersion in the water because of the water resistance nature of the binder. The prepared biodegradable composites meet most of the required properties for the indoor building insulation applications and show great potential to replace the conventional building material in current use.