Effect of fiber loading and surface treatment on flexural strength of polyester matrix reinforced with oil palm frond fiber wastes

Abstract

Natural fibers are abundantly available and potentially valuable biomass that is under-exploited. Regardless of many advantages, one shortcoming of use of natural fiber is the deformation after being formed into composite structure which is caused essentially by poor adhesion at the interface with the polymer matrix. In this study, processed oil palm frond fiber was surface - treated with phenylsilane and used in tangled mass and random orientation of varying lengths and diameters in the production of composites by hand lay-up technique with 10% to 70% fiber content in polyester matrix. The ‘as natural’ (untreated) and treated oil palm frond fiber composites were characterized with emphasis on the effect of fiber content and surface treatment on the flexural strength properties. As expected, the results show that the flexural strength properties of composites of treated oil palm frond fiber decreased with increasing fiber content of 69.65MPa at 10% fiber content to 52.98 MPa at 70% fiber content, unlike the ‘as natural’ (untreated) counterpart that exhibited virtually no change with increasing fiber content. The flexural modulus of treated oil palm frond fiber reinforced polyester composites increased with increasing fiber content as reported by other researchers. The non-correlation coefficient values between the untreated and treated oil palm frond fiber composites showed the non-stable characteristics of the material similar to most other natural plant fibers. The scanning electron microscopy result showed that the surface-treated oil palm frond fiber systems exhibited gradual but consistent failure pattern indicating improved bonding between the fiber surface and polyester matrix. In principle, the result showed that the prediction of failure behavior of oil palm frond fiber reinforced polyester composite will interest material selection designers especially in the replacement of wooden panels and in areas of less structural application that often find the use of more expensive glass fiber reinforced composites.