NMR Spin Relaxation, Self-Diffusion and Viscosity Studies of Poly(dimethylsiloxane)s Blended with Silicate Nanoparticles

摘要

Nuclear magnetic resonance spin-spin relaxation and self-diffusion measurements were used to investigate the mobility of poly(dimethylsiloxane) (PDMS) polymers when mixed with trimethylsilyl-treated silicate nanoparticles. The silicate can either solvate or reinforce the composite depending on the size of the particle. The smaller nanoparticle solvated all the polymer samples studied. The larger nanoparticle reinforced the two lowest molecular weight polymers at any concentration. When mixed with the higher molecular weight PDMS, the larger polysilicate caused a dramatic reduction in the mobility of the polymer chains above a critical concentration; however, an increase in mobility was observed below this critical concentration. This apparent increase in the mobility of the polymer chains was also manifested by a decrease in the zero-shear-rate viscosity of the mixture.