Polymer, Vol.54, No.21, 6026-6035, 2013
Novel approach to tune mechanics of beta-nucleation agent nucleated polypropylene: Role of oriented beta spherulite
In this study, a novel approach has been developed to introduce orientation to bundle-like beta spherulite in iPP samples. The addition of UHMWPE phase, which plays the role of maintaining orientation of iPP chains, into beta-nucleation agent nucleated iPP samples leads to the formation of oriented beta spherulite in the inner region of injection molded samples. Accordingly, both the tensile strength and impact strength of the sample have been improved. It proves that the arrangement of crystallites is another important factor to determine the toughness in addition to beta-crystal content, especially when the content is relatively high. Based on the investigated results, a schematic model about the formation of orientated beta crystals via the addition of UHMWPE is proposed. It's the first time that oriented beta spherulite is observed and investigated. Our study suggested an alternative approach to achieve good mechanics in polypropylene via introducing orientation to beta spherulite. (C) 2013 Elsevier Ltd. All rights reserved.