Polyurea/polysiloxane ceramer coatings

Tetraethylorthosilicate (TEOS) oligomers were prepared through the hydrolys is and condensation of TEOS with water. The mixture of TEOS oligomers was c haracterized by FT-IR, Si-29 NMR and electrospray ionization-mass spectrome try (ESI-MS). The ESI-MS and 29Si NMR data show molecular weight ranges fro m 400 to 2000 g/mol and many cyclic species exist in addition to linear oli gomers. The mechanical and tensile properties were evaluated as functions o f TEOS oligomer concentration and silane-functionalized isocyanurate concen tration. In addition, viscoelastic properties, thermal properties and morph ology of the ceramer coatings were investigated using dynamical mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and scanni ng electron microscopy (SEM) with energy dispersion X-ray analysis (EDAX). The data showed that ceramer coating properties were affected by both TEOS oligomer content and silane-functionalized isocyanurate content. Also, the adhesion was enhanced by incorporating the TEOS oligomers into the polyurea /polysiloxane coatings. (C) 2000 Elsevier Science S.A. All rights reserved.