Silicon‐29 solid‐state nuclear magnetic resonance spectroscopy of composite interfaces

Abstract The types of structures and bonds that are formed with silicons in the composite interface were studied using ²⁹Si cross‐polarization/magic angle sample spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR). The change in mobility of silane coupling agent bonded to silica, as compared with bulk hydrolyzed silane coupling agent, can be monitored by the change in line width and the shift of resonances to higher fields, as well as by the change in the silicon‐proton cross‐polarization time T_SiH. In the silane coupling agent‐matrix resin interface, the T_SiH values reflect the change in mobility as a function of the concentration and degree of hydrolysis of the silane coupling agent. It has been demonstrated that quantitative measurements of T_SiH can be used to investigate relative mobilities.