Phenyl silane treatment and carding process to improve the mechanical, thermal, and water-absorption properties of regenerated cellulose lyocell/polylactic acid bio-composites

Abstract

We fabricated a new composite material with increased lyocell (a form of rayon that consists of cellulose fiber made from dissolving wood pulp) content through a surface hydrophobic treatment using phenyl silane and fiber carding/melt pressing. A matrix of polylactic acid (PLA) was used to enhance the environment-friendly properties of the composite and a carding process was used to orient the fibers in the composite. The lyocell content was controlled from 10% to 90%. Cross direction (CD) and machine direction (MD) samples were prepared to confirm the effect of the fiber directionality of the composite on its mechanical properties. The MD samples performed better than the CD samples. The tensile, flexural, and impact strengths of the composite were increased by approximately 85%, 155%, and 55%, respectively, after surface treatment. In the heat-resistance evaluation, confirmed by pyrolysis, surface treatment showed an average improvement of more than 10 °C. The water-absorption characteristics showed dramatic improvement, with enhanced surface-wetting properties and excellent initial moisture-absorption properties in the immersion test. Based on the comprehensive results, we conclude that the performance of the composite was satisfactory even when the content of lyocell was 50% or more.