Effect of surface modified rice husk (RH) on the flexural properties of recycled HDPE/RH composite

Abstract

The hydrophilic nature of rice husks (RH) is incompatible with hydrophobic polymer matrix and has a tendency to form aggregates Therefore, surface modification plays a major role in order to improve and develop natural fiber reinforced polymer composites with better mechanical properties. In this study, modification of RH surfaces by alkali, acid and ultraviolet-ozonolysis (UV/O₃) treatment were carried out. The untreated and treated RH was characterised by FTIR, TGA and SEM. The composites of treated and untreated RH containing 30 wt% of RH fibers were then prepared by extrusion and comparative study is being done. Flexural strength of untreated RH, alkali-treated RH, acid-treated RH and UV/O₃-treated RH composites are 27.97, 31.25, 30.22 and 30.87 MPa respectively. All surface treated RH composites was found to improve its adhesion with polymer matrix. Flexural strength of composites filled with UV/O₃-treated RH shows similar results compared to alkali treatment. Therefore, UV/O₃ treatment can be used as an alternative method to modify RH surface in order to improve the adhesion between hydrophilic RH fibre and hydrophobic rHDPE polymer matrix.

Keywords:

• Surface modification
• rice husks
• flexural strength
• UV/O₃

Acknowledgement

The authors would like to gratefully acknowledge Kementerian Pengajian Tinggi Malaysia for the financial support under Long Term Research Grant Scheme (LRGS/TD/2012/USM-UKM/PT/05).