乙烯基单体改性蓖麻油基水性聚氨酯的研究

Study on Vinyl Monomer Modified Waterborne Polyurethane Based on Castor Oil

采用改性蓖麻油合成了软段中含不饱和双键的阴离子聚氨酯水分散液(MCPU),将其作为可聚合乳化剂和种子成分,分别与甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、苯乙烯(St)单体进行共聚,制得了PUA复合乳液MCPUA-MMA、MCPUA-BA和MCPUA-St。利用TEM、FT-IR、TG、DSC、XRD等手段考察了乳液及成膜的微观结构和性能。结果表明:MCPUA-MMA粒子形态不规整,MCPUA-BA和MCPUA-St粒子具有较清晰的核壳结构;红外谱图中3 300～3 350 cm-1处氢键化—NH吸收峰位置显示由MCPU到MCPUA-St、MCPUA-BA、MCPUA-MMA依次向低波移动;DSC研究表明PUA的Tg1相对于MCPU升高,MCPUA-BA和MCPUA-St的Tg2对应于MCPU下降,而MCPUA-MMA的Tg2相对MCPU升高;PUA胶膜的Tmax2相对MCPU均明显移向高温,膜的热稳定性提高;XRD表明合成的复合乳液膜均呈现出无定形形态。

A kind of anionic polyurethane dispersion （MCPU） containing unsaturated double bonds in the soft segments was synthesized with modified castor oil, and it was treated as polymerisable emulsifier and seed composition for emulsion eopolymerization of MCPU and different vinyl monomers, such as methyl methacrylate （MMA）, butyl acrylate（BA） and styrene （St） to prepare MCPUA- MMA, MCPUA-BA and MCPUA-St hybrid emulsions. Then TEM, laser particle size distribution analyzer, FF - IR, TG, DSC and XRD were used to characterize the morphology and properties of the emulsions and films. The results showed that MCPUA - MMA had irregular particle form, while MCPUA -BA and MCPUA -St showed clear core -shell structures. The position of hydrogen bonded --NH absorptions at 3 300 -3 350 cm-1 decreased at a sequence of MCPU, MCPUA - St, MCPUA - BA and MCPUA - MMA. The DSC tests indicated that Tg1of PUA increased compared with MCPU, Tg2 of MCPUA -BA and MCPUA -St decreased compared with MCPU, but Tg2 of MCPUA - MMA increased. Tmax2 of all the PUA films moved to the high temperature compared with MCPU, the heat sta- bility of al the PUA films increased. XRD results showed that all the films were amorphous.