Optimization of mechanical and moisture resistance of polyethylene wood plastic composites reinforced with nanocrystalline cellulose

Abstract

The addition of nanoparticles in polymers reinforced with wood fiber has been considered as one of the most effective way to improve the mechanical and physical properties of woodplastic composites. In this framework, the objective of this study was to investigate the effect of incorporation of nanocrystalline cellulose (NCC) on the mechanical properties and water absorption of wood-plastic composite made from high density polyethylene (HDPE) and wood flour. The first phase of this project involved the reinforcement of HDPE matrix with NCC using internal mixer. The effect of processing conditions, NCC content (0%, 3% and 10% wt.) and compatibilizing agent on the mechanical properties, water absorption rate and dispersion of NCC was analyzed. In the second phase, the best compounding conditions of HDPE/NCC nanocomposite, obtained from the first step, was used for the preparation of hybrid wood plastic composite. Mechanical properties (flexural and tensile) and water uptake were carried out to evaluate the performance of the composite. Mechanical results showed that the increase of NCC content until 10wt. % lead to the increase of flexural and tensile properties of HDPE/NCC nanocomposite. However, the SEM analysis of NCC dispersion showed the presence of big agglomerations. For Hybrid HDPE/NCC/WF composite, a partial replacement of wood flour with 10% NCC did not show any improvement in the flexural and tensile properties. This is due to the poor dispersion of NCC. In contrast a slight decrease of water absorption was detected in hybrid composite which can be caused by differences of hydrophilicity between wood flour and NCC. In further work, more tests with surface modification and liquid feeding of NCC should be done for successful development of hybrid wood nanocomposite. Also, the effect of different NCC concentration can be realized to identify the percolation threshold of composite reinforcement.

Date	4 Nov 2015
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Nicole R. Demarquette (Supervisor) & Anh Dung Ngô (Co-supervisor)