A nanostructured cellulose-based interphase layer to enhance the mechanical performance of glass fibre-reinforced polymer composites

In this study, we report the effect of sizing glass fibres (GFs) with tetramethylpiperidine-1-oxyl (TEMPO)-mediated cellulose nanocrystals (t-CNC) to improve the interfacial mechanical performance of glass fibre reinforced polymer composites (GFRP). These nanoparticles are introduced at different concentrations to yield a coating of t-CNCs which are (1) sparsely deposited at low concentrations, and (2) uniformly self-assembled over the glass fibre at a higher concentration. The mechanical, morphological and interphase results show that self-assembled CNC coating around a fibre provides better strengthening than sparsely deposited CNCs. Experimental results confirmed that GFs coated with self-assembled t-CNCs yielded a ~30% increase in the interlaminar shear strength (ILSS), 43% increase in flexural strength and 40% increase in flexural modulus of the GFRP composite. Strong nanoscale interactions between the t-CNC and GF, coupled with the formation of a high modulus gradient interphase layer, contributed to the significant improvement in the mechanical performance of t-CNC/GFRP composites.