Abstract
Nylon 6 short fibre was used to prepare composites based on blends of 85/15 Polystyrene (PS)/Natural rubber (NR) to study the effects of surface modification of the fibres and a compatibiliser based on PS. Initially, the loading of fibre, cut to 6 mm length, was varied from 0 to 3 wt.% in a 85/15 PS/NR blend. The composites were prepared on a Thermo Haake Rheocord mixer at 170 °C and sheeted out on a two-roll mill. Tensile, flexural and impact test samples were punched out from sheets and tested to study the mechanical and dynamic mechanical properties. It was found that the tensile properties, flexural properties and impact strength increased with the fibre content up to 1 wt.%, above which there was a significant deterioration in the properties. The fibre surface was further modified by alkali treatment and a reactive compatibiliser based on maleic anhydride-grafted-polystyrene (MA-g-PS) was used in an effort to improve the performance of the composites. The treated Nylon fibre in conjunction with the compatibiliser improved the tensile properties, flexural properties and impact strength. Dynamic mechanical analysis showed that by using the modified fibre and the compatibiliser, the storage modulus of the composite could be significantly improved. The fibre-matrix morphology was studied by SEM analysis of the tensile fractured specimens. Examination of the fibre extracted from the treated fibre composites revealed that some fraction of the matrix was bonded to the fibre surface. These results suggest that a combination of hydrolysed fibre and MA-g-PS increases the interfacial adhesion between the fibre and the matrix.