Highly transparent and flexible surface modified chitin nanofibers reinforced poly (methyl methacrylate) nanocomposites: Mechanical, thermal and optical studies

Abstract

Surface modified chitin nanofibers (SMCNFs) were easily prepared by reacting chitin powder with dodecenyl succinic anhydride (DDSA) and mechanical treatment. The resulted SMCNFs were homogenously dispersed in a series of organic solvents since more hydrophobic group was introduced on the surface of chitin nanofibers. Poly (methyl methacrylate) (PMMA)/SMCNFs nanocomposite films were prepared by simple solution casting method. The homogenous dispersion of the SMCNFs in the PMMA matrix was facilitated, due to the presence of hydrogen bonding and hydrophobic interactions between the nanofillers and the PMMA matrix. Thus, PMMA/SMCNFs nanocomposite films shown high optical transparency, which were nearly the same as the transmittance of the neat PMMA film. Tensile testing results revealed that, inclusion of SMCNFs in the PMMA matrix yielding a more fracture strain and tougher films than the neat PMMA film. Thermal analysis of the neat PMMA and nanocomposite films demonstrated that, the thermal stability of PMMA was significantly enhanced upon inclusion of SMCNFs. The remarkable reinforcement effect of SMCNFs in enhancing the mechanical and thermal properties of PMMA without altering its transparency was resulted from their crystallinity, high aspect ratio, and homogenous dispersibility in the DMF solvent and PMMA polymer matrix.