Environmentally friendly green materials from plant-based resources: Modification of soy protein using gellan and micro/nano-fibrillated cellulose

Fully biodegradable micro/nano-composite resins were prepared by reinforcing soy protein concentrate (SPC) with micro/nano-fibrillated cellulose (MFC) and then blending with gellan. The composite resins showed excellent mechanical and physical properties under testing conditions. Due to the high aspect ratio of MFC, excellent mechanical properties of MFC and MFC/SPC interfacial properties, the SPC (100 parts) reinforced with glycerol (1.5 parts) and MFC (40 parts) showed fracture stress of 88.2 MPa and Young's modulus of about 4.1 GPa, which are higher than those of many conventional petroleum-based plastics. MFC reinforced SPC composite resins were then further modified by blending with gellan to obtain further improvement in fracture stress and Young's modulus. SPC resin containing glycerol (1.5 parts), gellan (40 parts) and MFC (40 parts) had fracture stress of over 122 MPa and Young's modulus of about 5.8 GPa. Although the moisture sensitivity of the specimens was high, they have the potential to replace petroleum-based materials in many fields, particularly for indoor applications.