Solid-state organization of poly(methylmethacrylate)–poly(methylphenylsiloxane) based interpenetrating networks

Three interpenetrating networks based on polymethylphenylsiloxane (PMPS) and polymethylmethacrylate (PMMA) with different compositions were prepared. They were investigated using differential scanning calorimetry (DSC) and high-resolution solid-state 13C NMR techniques, in order to study the heterogeneous character of the domains involved in these materials at the nanoscopic scale. DSC observed broad glass transitions of the PMPS chains. 13C cross-polarization (CP) experiments clearly showed that the aromatic PMPS carbons have a rate of CP which is composition dependent, indicating that PMPS and PMMA chains are interpenetrating at a very low spatial scale. These results were supported by T1ρ(1H) and 13C line width measurements as a function of temperature. Moreover, T1ρ(1H) measurements indicated that PMMA chains are rather homogeneously distributed whereas PMPS chains belong either to interpenetrating domains or to PMPS-rich domains.