Reinforcing Linear Low-Density Polyethylene with Surfactant-Treated Microfibrillated Cellulose

Abstract

Due to its excellent mechanical properties and reinforcement abilities, cellulose has become a promising candidate for developing nanocomposites. However, cellulose agglomeration is an issue that must be solved. In this study, we treated microfibrillated cellulose (MFC) with a mixture of the non-ionic surfactants Span80 and Tween80 (ratio of 1:1) in order to prevent the intermolecular hydrogen bond aggregation of MFC during the process of MFC drying. We used a conical twin-screw extruder to melt compounds for the surfactant-treated MFC and powdered LLDPE. Furthermore, the extruded mixture was hot-pressed into a film, and we also tested the properties of the composite film. We can conclude that there was no agglomeration in the composite film according to microscopic observations and light transmittance test results. Furthermore, the dispersion of the surfactant-treated MFC (STMFC) was uniform until the STMFC filler increased to 10 wt%. The mechanical test results show that when the content of STMFC filler was 10 wt%, the mechanical properties of the composite were optimal. Compared to LLDPE, the STMFC/LLDPE composite film had an increase of 41.03% in tensile strength and an increase of 106.35% in Young’s modulus. Under this system, the DSC results show that the melting point of LLDPE increased from 125 to 131 °C. X-ray diffraction (XRD) results showed that the addition of STMFC did not change the crystallinity of the STMFC/LDPE composites, although the crystallite size increased.