Renewable cellulose is an outstanding candidate to prepare biomass-based optical management films with tunable transparency and haze. Micro-scale and nano-scale cellulose derived from the parenchyma cells (PC) and bamboo fibers (BF) of Dendrocalamus sinicus was first separated and then subjected to succinic esterification and mechanical defibrillation using three different methods: ultrasonication, high-speed blending, and microfluidization. Sustainable multiscale optical management films with tunable haze were obtained by changing the weight ratios of micro/nanoscale cellulose. The PC-based micro/nano cellulose (MNC) films obtained by microfluidization with the highest content of nanoscale cellulose (96.5 %) displayed the highest light transmittance (89.4 %) and tensile strength (164.3 MPa) but the lowest haze (32.0 %) and anti-glare ability. The BF-based MNC films obtained by ultrasonication with the lowest content of nanoscale cellulose (20.4 %) but the highest content of microscale cellulose (79.6 %) showed the highest haze (96.7 %), a medium light transmittance (81.3 %), and the outstanding anti-glare effects. The MNC films with both high in transparency (84.8–87.5 %) and haze (81.5–88.4 %) along with good strength and flexibility can be obtained by tuning the bamboo components and mechanical defibrillation methods. This study provides a green and facile way to fabricate sustainable optical management films.
Abstract High (14.9%), medium (2.4%) and low (0.1%) lignin-containing cellulosic fibers were processed through a micro-grinding method to mechanically produce lignocellulose nanofibrils (LCNFs). Effects of residual lignin on the mechanical defibrillation process were investigated in terms of the nanofibrils yields, the diameters of resultant LCNFs and the micro-grinding energy consumption. The results showed that the residual lignin delayed the initial defibrillation of cellulosic fibers due to its physical barrier. However, the residual lignin eventually facilitated the defibrillation and improved the maximum nanofibrils yields by 17.9–30.8%, and greatly reduced the diameters of the resultant LCNFs from 32.9 ± 7.7 to 9.2 ± 3.3 nm. The effects of lignin on counteracting the recombination reactions between the highly reactive cellulose radicals and hindering the aggregation of defibrillated fibrils through reducing the inter-fibrillar hydrogen bonding presumably resulted in the better eventual defibrillation of cellulosic fibrils. Graphical abstract
危险品化学品经营许可证（带存储）