Study Of The Properties And Preparation Of PDMS Coating Material

Coating materials can be divided two parts: inorganic coatings(metal coatings) and organic coatings. Inorganic coatings include protecting coatings and functional coatings. Organic thermal-protective coating is special coating material applied in many areas including aerospace, electron and electricity, textile, construction and so on. The most matrixes used in aerospace-plane and missile are epoxy resin, chlorosulphonated polyethylene, phenolic aldehyde, EP-polyurethane, polysulphide-EP and so on. But they have most demerits including high price, poor combination properties and high-temperature molding. PDMS has special merits including oxidation resistance, broad high and low temperature shift, frost resisting, resistance to ozone, electrical insulating, senseless physiology, corrosion resistance and damp resistance, and with no heat pressing equipment. Those merites cause researchers much interesting.Nowadays abroad studiers gradually focus on study of PDMS on solid engine shell. But domestic researchers are studying PDMS as thermal-protective coating material for no long time. In this paper, with different fillers and assistant agents, PDMS as the matrix of heat resistance coating material are studied.(1) The influence of PDMS matrix to tensile strength are studied. The results show that with the increasing of visicosity, that is, the molecular weight, the tensile strength of coating increase gradually and the summit of it is 1.7MPa. But the increasing of matrix visicosity make two shortcoming: firstly, the quatities of solution and other assistants will increase and subsequently the cost will rise; secondly, that cause the moulding prosess complex.(2) SiO₂ can reinforce the PDMS that it crosslinks with PDMS by physical or chemical mode. But most researchers omit the negatively thermal influence of SiO₂ for PDMS. In this paper, through TGA-DSC and SEM, the coating materials with SiO₂ was compared with pure PDMS coating material. The results showed that the temperature difference of weight loss 5% is reaching 133℃ and that of weight loss 10% is reaching 167℃. From the above analyzed, the study of thermal stability of...