Preparation and properties of dynamically vulcanised blends of isobutylene–isoprene rubber and isotactic polypropylene

Abstract

Dynamic vulcanisation was employed to prepare blends of isobutylene–isoprene rubber (IIR) and isotactic polypropylene (iPP) with superior properties. The preparation technology, the effects of the presence of IIR on the crystallisation properties of iPP and the mechanical properties of the IIR/iPP thermoplastic vulcanisates (TPVs) were investigated. It was revealed that, under regular shearing at 180°C, dynamic vulcanisation for 10 min produced IIR/iPP TPVs of excellent properties; while degradation occurred when the duration of vulcanisation was extended to 15 min. Incorporation of IIR into iPP dramatically reduced the size of the iPP spherulites, and thus decreased the melting temperature and the degree of crystallinity of the iPP. When the IIR content was 50 wt-%, maximally balanced mechanical properties of IIR/iPP TPVs were obtained with a Charpy impact strength of 53·6 kJ m−2 and a tensile strength of 31·3 MPa.