The use of high resolution 13C CP/MAS solid-state NMR spectroscopy in the investigation of chain mobility in PP-NBR blends

Blends of polypropylene (PP) and acrylonitrile rubber (NBR) were prepared in a Haake Rheocord Mixer model 9000, coupled with a mixer chamber (earn rotors), in a proportion of 60:40/PP:NBR. These blends were processed in the presence of either the phenolic resin SP-1045 ora derivative from cashew nut shell liquid (CNSL), in a concentration of 10%. Solid state C-13-NMR data using the cross-polarization mode, with magic-angle spinning (CP/MAS) and delayed contact time technique, was used to evaluate both the influence of the different phenolic resins and the addition technique on molecular mobility in the blends. Substantial differences have been observed concerning flexibility by changing the nature of the resin and the way it is introduced in the mixture. (C) 2001 Elsevier Science Ltd. All rights reserved.