Abstract
A simple blend (i.e., blend without curative) of 60/40 rubber/nylon‐12 with three different types of natural rubber (i.e., air‐dried sheet natural rubber (ADS) and epoxidized natural rubbers (ENR) with 25 and 50 mol% epoxide) was prepared by the melt‐mixing process. Influence of different types of rubbers and the level of epoxide groups in ENR molecules on the properties of the blends were investigated. It was found that all the blends exhibited a co‐continuous phase morphology. Furthermore, the ENR/nylon‐12 blends exhibited superior mechanical properties, stress relaxation behavior, thermal and rheological properties, and a finer grain morphology than that of the ADS/nylon‐12 blend. This may be attributed to the higher interfacial adhesion between the ENR and nylon‐12 phases via a chemical interaction of epoxide groups in ENR molecules and polar functional groups in the nylon‐12 molecules. Temperature scanning stress relaxation (TSSR) measurement was also performed. Improvement in stress relaxation and thermal resistance of the blends with ENR was observed. Moreover, the higher temperature coefficient and lower glass transition temperature (T~g~) of the nylon‐12 phase in the ENR‐50/nylon‐12 blends were found. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 32: 118–129, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20243