Synthesis and Application of Organic-inorganic Composite as Retardant Coatings and Highly Hydrophobic Polyurethane Coatings

The study mainly divided into two parts, in the first part of this study, we produced the environmentally green coatings. We used two kinds of environmentally nontoxic inorganic fillers：Alumina trihydrate and mica, to blend with waterborne polyurethane resin. Relied on waterborne polyurethane resin, the inorganic fillers bound to the wooden substrate, producing green flame-retardant coatings which could sustain the good performance of weather ability during the climatic variation (Temperature：20 ℃ to 50 ℃、Related humidity：0% to 90%).Observed by the Scanning Electron Microscope (SEM), the mica was proven stacked layer by layer on the surface of the coatings with its sheet structure, which could increase the flame resistance and protect substrate effectively. Cone calorimeter was used to test the flame-retardant coatings, and we could reach the inflammable materials of Grade II.
In the second part of this study, by using colloidal silica as the precursor, we modified hydrocarbon structure on the surface by n-Octadecyltrimethoxysilane (ODTMS) which became a highly hydrophobic inorganic material. Fourier Transform Infrared Spectrometer (FT-IR) was used to assay the reaction. We focused on the different modified ratio of colloidal silica and the different blend ratio with polyurethane. Contact angle test was used to test its hydrophobicity, we could achieve the superhydrophobic contact angle 150.10o. The surface was observed by the Scanning Electron Microscope (SEM) to confirm rough surface with the increase of the modified ratio of colloidal silica. With the increase of the blended ratio of modified silica with the polyurethane, we also could obtain the rough surface, and increased its hydrophobicity.