Abstract
Mechanisms of micro- and nano-defibrillation of hemp fibers are studied and discussed. The results, generated from subjecting hemp fibers to mechanical shearing (MS), combined MS-heating (MSH), and combined MSH-chemical processes, confirmed that the micro/nano-architecture of cell wall of hemp fibers facilitated the defibrillation during nano process and the different fibril construction and chemical constituents between cell wall layers (i.e., lamella, primary and secondary layers) determined the nature of process and processing parameters to be applied while enabling processes to be tailored for various end products. A low fibril concentration within lamella and primary layers made the regions vulnerable to decompose when wet and heated, and led to the breakdown of cell walls to the secondary layers and consequently microfibril of S2-layer. Inherent and processing macro- and micro-defects of hemp fibers could be the first accessible points for processing agents and initiating mechanical decomposition when the nano process took place. Nano processing parameters, e.g., heat and chemical agents, were significant contributors to the defibrillation of cellular micro/nano particles and hence the efficacy and productivity of nano process due to the different sensibility of chemical compounds within various layers of cell walls.