Physiochemical treatments such as ultrasonic wave or microwave were applied to the plant fiber materials to obtain high efficiency in virtue of intensification of heat and mass transfer (Lu et al., 2013). By using microwave assisted technique, it will generate heat by direct conversion of electromagnetic energy which will help in reducing energy consuming and reaction time compared to conventional heating (Lu et al., 2013). While by using ultrasonic wave, a strong mechanical oscillating energy will be produced and effectively breakdown interaction force between cellulose (Karim et al., 2015).
Figure 1.1 Schematic diagram for tree hierarchical structure (Moon et al., 2011)
Numerous preparations methods had been evaluated to obtain stable and usable material for NCC. Based on previous work, nano-crystalline cellulose was prepared by sulphuric acid hydrolysis of cellulose raw materials in aqueous solution, and then freeze-dried (Yu et al., 2013). During acid hydrolysis, amorphous regions are removed leaving only crystalline cellulose (Jasmani & Adnan, 2017). In general, the sulphate group will be attached to the surface of the NCC during the hydrolysis that will bring a decrease in thermal stability. NCC dominates more advantages than cellulose fibers. Such as high surface area, specific strength and modulus and having unique optical properties (Peng et al., 2011). NCC has great strength because of its dense and ordered crystalline structure while its elasticity for the perfect crystal of native cellulose had been estimated between 130 and 250 GPa and tensile strength between 0.8 and 10 GPa (Kos et al., 2014).
Demand of products that made from renewable and sustainable resources had been increasingly needed by consumers industry and government. For the past thousand years, our society had been used natural cellulose as based materials and it is still on going. They develop functionality, flexibility and high mechanical strength by
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