Compatibilizing effect of styrene-maleic anhydride copolymer on the properties of polyamide-6/liquid crystalline copolyester composites

Liquid crystalline polymer-polyamide-6 (LCP/PA6) composites containing 20 w t % LCP content were compatibilized by a random styrene-maleic anhydride co polymer (RSMA). The blending was performed via extrusion followed by inject ion molding. The LCP employed was a commercial copolyester, Vectra A950. Th e dynamic mechanical (DMA), rheological, thermal, and mechanical properties as well as the morphology of the composites were studied. The DMA and rheo logical results showed that RSMA. is an effective compatibilizer for LCP/PA 6 blends. The mechanical measurements showed that the stiffness, tensile st rength, and toughness of the in situ composites are generally improved with increasing RSMA content. However, these mechanical properties deteriorated considerably when RSMA content was above 10 wt; %. The drop-weight dart im pact test was also applied to analyze the toughening behavior of these comp osites. The results show that the maximum impact force (F-max) and crack-in itiation energy (E-init) tend to increase with increasing RSMA content. Fro m these results, it appeared that RSMA prolongs the crack-initiation time a nd increases the energies for crack initiation and impact fracture, thereby leading to toughening of LCP/PA6 in situ composites. Finally, the correlat ion between the mechanical properties and morphology of the blends is discu ssed. (C) 2000 John Wiley & Sons, inc. J Appl Polym Sci 77: 1964-1974, 2000 .