Synthesis & characterization of benzaldehyde modified acetoacetylated polyesters for polyurethane/urea coatings

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• 作者：Shaik Allauddin ; Kishore K. Jena ; Aswini K. Mishra ; K.R. Radhika ; Ramanuj Narayan ; K.V.S.N. Raju ; ^{drkvsnraju@gmail.com} ; ^{kvsnraju@iict.res.in}
• 关键词：Acetoacetylated polyester ; Polyurethane ; Benzaldehyde ; FTIR ; TGA ; DMTA
• 刊名：Progress in Organic Coatings
• 出版年：2012
• 期刊代码：70_03009440
• 类别：ce
• 出版时间：September-October, 2012
• 卷：75
• 期：1-2
• 页码：131-138
• 文件大小：1383 K

摘要

The present work describes the synthesis and characterization of high solid polyurethane (PU) coatings prepared from acetoacetylated polyester (EAA-PE), 4,4鈥?methylene diisocyanate (MDI) and benzaldehyde (BNZ). For this initially, the hydroxyl terminated polyester polyol (PE) was prepared and was further modified by ethyl acetoacetate to prepare the EAA-PE. In the next step, part of the CH₂ groups of the EAA-PE (10%, 20%, and 30%) was modified with benzaldehyde to get the different benzaldehyde modified acetoacetylated polyesters (BNZ-EAA-PEs). Finally, the different PU and BNZ modified PU coatings were prepared by reacting the EAA-PEs and BNZ-EAA-PEs with MDI at CH₂/NCO eq. ratio of 1:1.4. The molecular structure of the EAA-PEs and BNZ-EAA-PEs were confirmed by ¹H, ¹³C NMR and FTIR spectroscopy. The molecular weight and glass transition temperatures of different EAA-PEs were determined by GPC and DSC instruments respectively. The benzaldehyde crosslinked polyurethane coatings properties were studied by FTIR, TGA, DMTA, UTM, DSC, SEM and contact angle methods. These results suggest that thermal stability, tensile strength and contact angle of the BNZ modified PU is higher than the unmodified ones and also increase with increasing BNZ concentration.