Porosity, density and mechanical properties of the paper of steam exploded bamboo microfibers controlled by nanofibrillated cellulose

Abstract

This study focused on preparation of microfibers from bamboo culms using steam explosion with and without chemical treatments, and utilization of the isolated fibers in formation of bamboo paper fabricated with nanofibrillated cellulose (NFC). Compared with those obtained from the steam explosion alone (S), the bamboo microfibers isolated using the steam explosion followed by bleaching process (S/A) exhibited a significantly reduced fiber width of 7.5 μm and a markedly increased cellulose content of 97.85%. The S/A fiber showed an increased decomposition temperature, corresponding with lower contents of hemicellulose and lignin than those of the S fiber. The S/A microfibers were subsequently proceeded to paper formation. Physical and mechanical properties of the paper with an introduction of different NFC concentrations (0–50 wt%) were investigated. The linear relationship between the density, porosity and mechanical properties of the paper and NFC contents was observed. The more the NFC content, the greater the density and the lower the porosity the paper exhibited. At 50 wt% NFC, the paper density increased to 0.64 g cm−3, and the paper porosity decreased to 57.0% whereas the paper without NFC showed a density of 0.39 g cm−3 and porosity of 73.6%. Tensile strength and strain of the paper composed with 50 wt% NFC were 10-fold and 3-fold, respectively, greater than those of the paper without NFC. The addition of NFC could manifest paper mechanical properties and porosity within the paper structure, which would be useful for scaffold and membrane applications. Keywords: Bamboo, Mechanical properties, Paper, Nanofibrillated cellulose, Steam explosion, Microfibers, Nanofibers