Nuclear magnetic resonance is ideally suited for the investigation of materials with low order such as polymers. In addition the high selectivity facilitates the investigation of both the polymer component and the filler. Steps of the modification of fillers performed to enhance the compatibility with polymers are followed in aluminium solid-state NMR which is via the quadrupole interaction particularly sensitive to the symmetry around the nucleus under study. Proton relaxation NMR gives insight into the polymer dynamics over a wide range of correlation times. In combination with line narrowing techniques this provides both chemical selectivity and sufficient sensitivity for thin polymer coatings on solid substrates which are used as model systems e.g to compare polymer brushes with bulk polymers. Dedicated experiments are developed for the selective study of the interface between the polymer and the filler. Magnetization generated in the filler selectively is transferred across the interface over a short distance to permit the acquisition of NMR spectra from the interface region for comparison with bulk spectra. The studies are complete with investigations of the dynamics in the polymer under external mechanical forces. Low-field NMR is combined with stress-strain experiments. Slowing down of the polymer dynamics as a result of external stress is observed and regain of the dynamics with time under constant load from mechanical stress relaxation. The influence of fillers in the melt is seen in rheological NMR in a Couette cell is seen in the reduced mobility in the presenc of teh filler. Shear in many cases leads to a loss of entanglements and thus enhanced chain dynamics as opposed to the expected reduction of mobility from shear-induced orientation.