Surlyn®/silicate hybrid materials. I. Polymer in situ sol–gel process and structure characterization

We report the creation of a new organic/inorganic hybrid material that results from sol–gel reactions for tetraethylorthosilicate (TEOS) within poly[ethylene‐co‐methacrylic acid], as well as within a Zn⁺² partially neutralized form of this copolymer (Surlyn®). FTIR and ²⁹Si solid‐state NMR spectroscopic probes yield information regarding molecular connectivity within the in situ grown silicate structures. FTIR analyses of Surlyn® matrix bands suggest that strong molecular level interactions between the organic and inorganic phases are not present, although there is other evidence that these phases are mechanically coupled on a larger dimensional scale. The ²⁹Si solid‐state NMR analyses indicate mainly Q₃ and Q₄ coordination states about the SiO₄ substructures, regardless of silicate content, which is in general agreement with the interpretation of the FTIR results that show incomplete condensation. Environmental scanning electron microscopy and energy dispersive X‐ray analysis results reinforce the conclusion that a significant silicate component is incorporated deep within TEOS‐treated films. Differential scanning calorimetry studies of Surlyn®‐Zn⁺²/silicate hybrids suggest that silicate incorporation essentially does not disrupt crystallinity. Thermogravimetric analyses show practically no change in the degradation onset temperature, which is consistent with organic/inorganic phase separation. The general conclusion is that a silicate phase can indeed be incorporated within this acid copolymer, as well as its Zn⁺² ionomeric form, via in situ sol–gel processes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2832–2844, 2000