Polyurea/polysiloxane ceramer coatings

Tetraethylorthosilicate (TEOS) oligomers were prepared through the hydrolysis and condensation of TEOS with water. The mixture of TEOS oligomers was characterized by FT-IR, Si-29 NMR and electrospray ionization-mass spectrometry (ESI-MS). The ESI-MS and 29Si NMR data show molecular weight ranges from 400 to 2000 g/mol and many cyclic species exist in addition to linear oligomers. The mechanical and tensile properties were evaluated as functions of TEOS oligomer concentration and silane-functionalized isocyanurate concentration. In addition, viscoelastic properties, thermal properties and morphology of the ceramer coatings were investigated using dynamical mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC) and scanning 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.