Morphology and dynamic mechanical properties of long glass fiber-reinforced polyamide 6 composites

Long glass fiber-reinforced polyamide 6 (LGF–PA6) composites were prepared by using self-designed impregnation device. Polypropylene grafted with maleic anhydride (PP-g-MAH) and polyolefin elastomer grafted with maleic anhydride (POE-g-MAH) were chosen as compatibilizers. Dynamic mechanical properties of LGF–PA6 composites were investigated by using dynamic mechanical analysis (DMA). The DMA measurement results showed that test frequency, long glass fiber content and compatibilizers had an influence on dynamic mechanical properties and glass transition temperature ( T g ) of LGF–PA6 composites. The frequency had a complex influence on storage modulus ( E ′), loss modulus ( E ″) and loss tangent (tan δ ). The T g of the composites is shifted to high temperature with the increasing of test frequency and was affected insignificantly by the glass fiber content. Storage modulus and loss modulus ( E ″) increased with the increasing fiber content, while the tan δ decreased. The effect of the addition of PP-g-MAH and POE-g-MAH on the dynamic mechanical properties of LGF–PA6 composites was complex. Scanning electron microscopy (SEM) was used to investigate the morphology of the fractured composites surface. The SEM results suggested that the PP-g-MAH and POE-g-MAH both improved the fiber/matrix interface adhesion, which was consistent with the DMA measurement results.