Chapter 9. Polymer Blends, Nanocomposites, Rubbers and π-Conjugated Polymers

This chapter presents the solid-state NMR investigations of polymer mixture materials, such as polymer blends and composites with inorganic fillers, rubbers and synthetic functional π-conjugate polymers. They are poly(metacrylic acid)/poly(vinyl acetate) (PMAA/PVAc) blends, polyketone/polyamide (PK/PA) alloys, polyurethane/silk fibroin (PU/SF) blends, poly(vinyl alcohol)/clay (PVA/clay) nanocomposites, nylon-6/montmorillonite-clay (nylon-6/MMT) nanocomposites, polystyrene-poly(ethylene oxide) block copolymer/hectorite-clay (PS-PEO/HCT) nanocomposites, styrene-butadiene rubbers (SBR), acrylonitrile-butadiene rubbers (NBR), natural rubbers (NR) and π-conjugated microporous polymers (CMP). Quantitative analyses of inter-polymer hydrogen bonding, which makes 13C chemical shifts move toward the lower field, the humidity effect on 13C NMR spectra, the blending effect on the stability of the crystalline phase and the effect of 1H spin diffusion on 1H spin–lattice relaxation are introduced. The interaction between polymer chains and inorganic clay layers is also exhibited. Heteronuclear correlation NMR spectroscopy shows a proof of existence of the interactions between polymers and clay layers. Stability of the organic modifier treated on the clay surface is described. The paramagnetic source naturally contained in clay layers is useful to evaluate the stability of organic modifiers. For rubbers, it is introduced that the molecular motion and the chain direction are significantly affected by fast magic-angle spinning (MAS). The degradation of rubber seals is also discussed with 1H spin–spin relaxation. Finally, the structural analysis of two kinds of CMPs by 19F–13C CPMAS NMR experiments is touched upon briefly.