| As we know, organosilicone sealant has been widely applied ever since, but low surface tension and surface energy of organosilicon sealant makes it difficult to be painted, which restricted it's use badly. It is thus the purpose of present dissertation to improve surface paintability of silicone sealant through the investigations of filler surface treatment, promoters addition and main chain's modification.The effects of different types of calcium carbonate and surface treating agents on paintability of silicone sealants were compared following standard ASTM method. But no promising results were obtained due to CaCO3 sedimentation and the soft segments migration of polysiloxanes to the surface. However, the surface paintability could be partially increased by increasing the filler content, decreasing filler's specific gravity and average particle size.There different kind of promoters, namely Promoter SD, Promoter AN and Promoter US which contains respectively amido(CONH)and double band, cyano-group(CN) and mercapto(SH), were examed and its effect on paintability were analyzed. The results revealed that with incorporation of Promoter SD or DL-602, the surface paintability was improved effectively. Additionally, it was found that the surface paintability are much dependent on both the coating time and testingperiod. Generally speaking, the longer the testing period, the shorter the painting time, the better the final results.For the consideration of increasing coverage of coating and stability, the main component of sealants, polysiloxane, was further modified through the co-polymerization in the presence of cyclic oligmers (D4) and DL-602. The incorporated amino groups react with oleic acid, which gives rise to the formation of amido group. Testing outcome confirmed that by incorporating this modified polysiloxanes, the surface paintability was markedly improved both for the oil-based alkyd coating and the hydrophilic acrylic latex coating.
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