Study of plant and tunicate based nanocrystalline cellulose in hybrid polymeric nanocomposites

Nanocrystalline cellulose (NCC) is a sustainable and renewable nanomaterial which can be defined as the nanoscale crystalline region of cellulose fibrils. The present work describes polyvinyl alcohol (PVA) based nanocomposite materials containing reinforcing low aspect ratio NCC sourced from plants and high aspect ratio NCC from a local invasive tunicate species. The effect of size and surface chemistry of the NCC reinforcement on the mechanical, thermal and morphological properties of PVA based nanocomposites is studied. Hybrid nanocomposites which contain both plant and tunicate sourced NCC within the PVA matrix are also documented. To our best knowledge, this represents the first known study describing the effect of NCC with varying size and surface chemistry combined within PVA to form hybrid PVA–NCC nanocomposites. In all cases, increasing mechanical reinforcement is observed as NCC content is increased, which varies in magnitude with NCC aspect ratio and surface chemistry. A notable improvement in thermal stability is also observed in all nanocomposites when NCC content is increased. Precursor materials and the resulting nanocomposites are well characterized by transmission electron microscopy, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, elemental analysis and powder X-ray diffraction.