Summary: A series of NBC/phenolic resin composites, containing 0, 1, 3, 5 or 7 wt.‐% of a powdered phenolic resin of different particle diameter, was prepared by the reaction injection molding (RIM) process. It was determined by SEM analysis that there exists a strong interaction between particles and matrix and that such interaction occurs through hydrogen‐type bonds as determined by FTIR analysis. According to the results it is thought that the glass transition temperature of the NBC/phenolic resin composites depends on two competing factors: the rigidity promoted by the hard solid filler and the flexibility imparted by the nylon 6 amorphous phase, whose proportion becomes more important with increasing amounts of phenolic resin particles. The elastic and flexural moduli of the NBC were improved by the addition of phenolic resin confirming the reinforcing effect of this filler. On the contrary, the impact strength diminishes with increasing amounts of phenolic resin, although this property is strongly dependent on the particle diameter.
SEM micrograph of the nylon 6‐polyesteramide block copolymer (80/20).
