Preparation, characterisation and application of biodegradable coarse wool-poly(lactic acid) sandwich composite

The presented study outlines the development and characterisation of a sandwich composite comprising coarse wool and polylactic acid (PLA). The PLA granules were placed in between two coarse wool fabrics and the sandwich model composite was prepared through hot pressing. The morphological, thermal, physico-mechanical and aging properties of the composite were systematically analysed. Additionally, as a part of product development, an acoustic panel was fabricated with the developed composites. The composite exhibited high stiffness, displaying a modulus of 964 MPa. The XRD analysis indicated that the wool-PLA composite is amorphous in nature. In the water diffusion test, the wool-PLA composite demonstrated permeability to water, resulting in 31% gain upon saturation. The accelerated UV aging did not mark significant changes in the tensile strength of the composite. However, the thermal aging led to a drastic reduction in tensile strength. During the soil burial test for 120 days, the composite lost 20% of its weight. The acoustic panel developed from the wool-PLA composite exhibited an impressive noise reduction coefficient of 0.97 and excellent thermal resistance (0.055 m² W/K). The newly developed wool-PLA composite could find potential applications in biodegradable secondary ceilings, partition boards, thermal and acoustic panels.