Influence of Thermocompression Conditions on the Properties and Chemical Composition of Bio-Based Materials Derived from Lignocellulosic Biomass

Abstract

The aim of this study was to assess the influence of thermocompression conditions on lignocellulosic biomasses such as sugarcane bagasse (SCB) in the production of 100% binderless bio-based materials. Five parameters were investigated: pressure applied (7–102 MPa), molding temperature (60–240 °C), molding time (5–30 min), fiber/fine-particle ratio (0/100–100/0) and moisture content (0–20%). These parameters affected the properties and chemical composition of the materials. The density ranged from 1198 to 1507 kg/m3, the flexural modulus from 0.9 to 6.9 GPa and the flexural strength at breaking point from 6.1 to 43.6 MPa. Water absorption (WA) and thickness swelling (TS) values ranged from 21% to 240% and from 9% to 208%, respectively. Higher mechanical properties were obtained using SCB with fine particles, low moisture content (4–10%) and high temperature (≥200 °C) and pressure (≥68 MPa), while water resistance was improved using more severe thermocompression conditions with the highest temperature (240 °C) and time (30 min) or a higher moisture content (≥12.5%). Correlations were noted between the mechanical properties and density, and the material obtained with only fine particles had the highest mechanical properties and density. Material obtained with a 30 min molding time had the lowest WA and TS due to internal chemical reorganization followed by hemicellulose hydrolysis into water-soluble extractables.