Abstract: In this study, flame-retardant composites were prepared with polyamide 66 (PA66) as a matrix, silicon rubber with core-shell structure as a toughening agent, glass fibers with round or flat cross-section as a reinforcing phase. The tensile properties, notched impact strength, and flame retardancy of the composites were characterized via universal test machine, Charpy impact tester, and UL 94 test system, respectively. It showed that the impact strength of the composites experienced a continuous increase with increasing rubber content. Moreover, the composites with flat glass fiber had better impact property than that with round glass fiber, regardless the rubber content. The composites demonstrated the best comprehensive performance when the rubber content was 6 wt.%: the notched impact strength increased by 10 % based on those without rubber at a cost of decrease in tensile properties only 15 %. More importantly, the composites passed UL 94 V-0 rating.

Key words: polyamide, core-shell structure silicon rubber, glass fiber, halogen-free flame-retardancy, toughening