Effect of Maleated Compatibiliser (PBS-g-MA) Addition on the Flexural Properties and Water Absorption of Poly(butylene succinate)/Kenaf Bast Fibre Composites

Poly(butylene succinate) (PBS) composites with 30 wt.% loading of kenaf bast fibre (KBF) were compatibilised with 5 wt.% maleated PBS (PBS-g-MA). The maleic anhydride (MA) concentration in the compatibiliser was either 3, 5, 7 or 10 phr. In general, the compatibilised composites showed better flexural properties than the un-compatibilised composite. The highest increment in the flexural strength and modulus of 12.7 and 8.9%, respectively, were obtained with the addition of PBS-g-MA with MA concentration of 5 phr. Compatibilised and un-compatibilised PBS/KBF composites were immersed in distilled water for 90 days. The absorption of water by all the composites was observed to follow Fick’s law. The equilibrium moisture content, M m, of the composites with PBS-g-MA at 3, 5 and 7 phr of MA concentrations was lower than that of the un-compatibilised composite due to improved fiber-matrix interfacial adhesion and reduction of voids content. Both un-compatibilised and compatibilised composites showed dimensional instability after the water absorption. This was probably due to the degradation of the fibre-matrix interfacial adhesion and fibre integrity. The flexural properties of these composites decreased after the water absorption. After re-drying only some of the flexural properties were recovered from plasticizing effect of water.