Impact of thermomechanical pretreatment by twin-screw extrusion on the properties of bio-based materials from sugarcane bagasse obtained by thermocompression

[Display omitted] •Bio-based materials were produced by thermocompression from SCB extrudates.•Twin-screw extrusion facilitated fiber defibration and particle size reduction.•Materials from extrudate showed superior mechanical properties and water resistance.•High flexural properties achieved with 1.25 L/S ratio and restrictive screw profile.•Best water resistance observed with 0.4 L/S ratio and more shearing screw profile. The aim of this study was to produce binderless materials by thermocompression from lignocellulosic biomass pretreated using twin-screw extrusion. The impact of twin-screw extrusion pretreatment on sugarcane bagasse (SCB) was evaluated, along with the effects of two associated parameters: the liquid-to-solid (L/S) ratio and the screw profile, using three different mechanical shear rates. It was shown that twin-screw extrusion pretreatment resulted in materials with improved properties as compared to those obtained with untreated SCB. The mechanical properties and water resistance of materials obtained after pretreatment were mainly impacted by the screw profile. The flexural modulus increased from 5.3 to 6.1GPa and the flexural strength from 39.0 to 55.5 MPa. Water absorption (WA) from the thermocompressed materials ranged from 25 to 62 %, and thickness swelling (TS) from 24 to 67 %. Materials obtained with a 0.4 L/S ratio had lower flexural strength but the best water resistance. For the same L/S ratio, the use of a more shearing screw profile improved the material properties, especially the water resistance. The best material was produced with pretreated SCB using a 1.25 L/S ratio with the most restrictive screw profile, resulting in materials with a 5.6GPa flexural modulus, 55.5 MPa flexural strength, and WA and TS values of 44 % and 42 %, respectively.