The Influence of Pulping Process and Energy Consumption on Properties of Nanofibrillated Lignocellulose (NFLC) Films Isolated from Wheat Straw

The present research has primarily focused on the production of nanofibrillated lignocellulose (NFLC) instead of nanofibrillated cellulose (NFC), which could be produced with less energy and is expected to have similar uses as NFC, especially in the sectors where the transparency is not important. Furthermore, the effect of energy consumption needed for NFLC production and also the influence of pulping methods on the produced NFLC properties has been surveyed. Through mechanical refining and different passes in microfluidizer, the results showed the average diameter of NFLC declined from around 19000 nm to 36 nm. Soda-NFLC films had higher calliper and lower roughness, compared to those of MEA at given energy consumption in refiner and microfluidizer. For both kinds of pulps, the optimum level of energy consumption to reach the best tensile index of NFLC films was 258 kWh/t, with three passes through microfluidizer. More increase in the number of passes and pressure only resulted in increasing of energy consumption without any positive effect on improving the tensile index. The maximum tensile indices of NFLC films obtained from soda and MEA pulping processes were 113.5 and 119.86 N·m/g, respectively. The burst index of 8.5 kP·m2/g and the energy consumption of 458 kWh/t were obtained for five passes through microfluidizer. With the increase of the number of passes of soda and MEA samples through microfluidizer, the opacity decreased but transparency increased.