Surface Hydrophobization of Micro- and Nanofibrillated Cellulose and Blending Property in PLA Nanocomposites

摘要

In this research, we have investigated the influence of differet fiber morphologies including microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) on the uniformity of mixing and extrusion properties with a bio- based poly (lactic acid) or PLA polymer matrix. The polar nature of PLA was also expected to result in enhanced interfacial bonding with the MFC, but the highest polarity of microfibrillated cellulose compare to polarity of PLA leads to agglomeration of MFC in polymer matrix phase. At present, its aggregation and flocculation problem has restricted the use of these reinforcements in polymer matrix. The mixing of MFC/NFC fibers with PLA has been improved by an in-situ surface modification of the cellulose fibers, resulting in the deposition of poly(styrene-co- maleimide) or SMI nanoparticles on the fiber surface. By controlling the MFC consistency and its surface properties during the production phase in a microfluidizer, the degree of dispersion could be varied in order to reach dispersive and distributive mixing. Depending on the number of homogenization steps and in-situ surface modification of the MFC, the degree of defibrillation and surface charges on the cellulose fibers could be varied. The further optimization of the MFC/PLA compositions has been based on rheometrical testing to evaluate the concentration ranges for mixing MFC as a filler into PLA composites.