Rubber toughening of nylon 6 with epoxidized natural rubber

This paper focuses on the use of epoxidized natural rubber (ENR) as a toughening agent for nylon 6 (PA6). Natural rubber (NR) was used to compare with ENR. Polymer blends were prepared by using a twin-screw extruder and pressing as a sheet in a compression molding machine. It was found that NR and ENR decreased yield stress and tensile strength but slightly increased elongation at break of PA6. NR slightly decreased impact strength of PA6, whereas this property increased up to sixfold by blending with ENR. This phenomenon could be explained in terms of blend morphology. Too large a particle diameter of NR was a cause of the premature failure. The impact strength of the blends increased with increasing ENR content. Rubber particle diameter also increased but was still much smaller than natural rubber particles. Phenolic resin was employed for crosslinking ENR. Compounded ENR increased tensile properties but decreased impact strength of the blends. This was because the morphology of ENR was changed from small particles to large patches of rubber after vulcanization.