Microfibrillated cellulose from sweet sorghum (Shorghum Bicolor (L.) Moench) fiber by twin screw extruder and its charateristics on polylactic acid biocomposites

High tensile strength and modulus could be obtained by microfibrillated cellulose (MFC) addition into PLA matric. MFC production from sweet sorghum fiber with twin screw extruder (TSE) could be an effective mechanical treatment. The objective of this research is to study the effectivity of twin screw extruders for MFC production from sweet sorghum fiber and to analyze its effect on PLA biocomposites properties. Sorghum fiber was firstly delignificated with alkaline treatments and bleached with sodium peroxide solution to produce high cellulose content of fiber. Bleached sorghum fiber was then passed through into TSE for 1, 3, and 5 passes. Afterward, PLA biocomposites with MFC from TSE process were produced by the solvent casting method. Twin screw extruder with co-rotating intermeshing flow is effective for defibrillation and size reduction of cellulose fibers which could achieve 1-10 μm in diameter and millimeters in length.. The tensile strength of PLAM_TSE5 increase 4.54% in 50.60 Mpa and modulus of elasticity increase 40.36% in 2.82 Gpa. Storage modulus of PLAM_TSE5 also increases 10.64% in 3.088 Mpa compare to pure PLA.