Structure and mechanism of functional isotactic polypropylene via in situ chlorination graft copolymerization

This paper discusses the structure and mechanism of maleic anhydride (MAH) grafted onto isotactic polypropylene (iPP) via in situ chlorination graft copolymerization (ISCGC). The molecular structure of the grafted iPP was characterized using (1)H NMR and (13)C NMR spectroscopy, viscosity-average molecular weight and gel content. The structure of un-grafted MAH present in the reaction system was investigated using Fourier transform infrared spectroscopy in order to explore the grafting of MAH on iPP. The main side-reactions, including iPP chain scission and crosslinking, during the grafting reaction were explored. From the experimental results obtained, the reason for controlled macromolecular chain degradation and crosslinking of grafted iPP in ISCGC is proposed. Based on the structural characterization of the grafted polymer, the mechanism of grafting onto iPP obtained via ISCGC was deduced. Mechanical properties, both static and dynamic, of grafted iPP were also investigated and the results showed that the properties of the material changed due to grafted MAH. (C) 2011 Society of Chemical Industr