Investigation of possibility of using Cellulose – based Nanofibers for reinforcement of polymer composites

Abstract

This thesis focuses on the use of cellulose-based natural fiber on the example of date palm midribs in form of nano particles as reinforcement to Epoxy and Polyester resins. Date palm midribs were first roughly broken to lengths in macro scale and further milled down to nano scale, using a self-designed and constructed planetary ball mill, resulting in particles sizes ranging between 67 to 276.5 nm. Nanocomposites were prepared using a casting technique, where compounds of varying compositions (0.5 up to 5 wt% nanofiber reinforcement) were poured into rubber molds of requested shape. The mechanical performance of the composites was evaluated in terms of tensile, flexural and impact properties in addition to hardness. Micrographic analysis was performed to further draw correlations between composite structure and mechanical behaviour. Analysis of variance (ANOVA) was conducted to make clear statements about the significance of the effect of filler content on the various properties. Mechanical testing shows that there is a positive effect of nano-reinforcement on impact strength and hardness. However, regarding tensile properties, no positive effect was recorded. Bending properties were proved to slightly improve through the nano-reinforcement of polyester composites, whereas the incorporation of nano filler in epoxy lead to deteriorated properties. SEM micrograph analysis shows that there is good dispersion of nano date palm midrib fibres at contents of up to 1 wt%. With increasing contents, however, agglomeration of nano particles as well as voids could be observed. This explains the deteriorated mechanical properties of both epoxy- and polyester- based nano date palm fibre composites at increased reinforcement content.

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