A new kind of beta nucleating agent, multi-wall carbon nanotube (MWCNT)-supported calcium pimelate was introduced into polyamide 6 (PA 6)/isotactic polypropylene (iPP; 10/90 by weight) blend and the thermal properties, morphology, and mechanical properties were investigated. The results showed that beta-iPP appeared at low content of MWCNT-supported calcium pimelate which surmounted the a-nucleating effect of PA 6 for iPP, and the content of beta-iPP increased with increasing content of MWCNT-supported calcium pimelate. The impact strength, elongation at break, and flexural modulus were improved with increasing content of MWCNT-supported calcium pimelate without significantly deteriorating the tensile strength. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012