扩链型光固化聚氨酯丙烯酸酯水性体系研究

CHAIN-EXTENDED UV-CURABLE WATERBORNE POLYURETHANE-ACRYLATE

由甲苯二异氰酸酯、聚乙二醇、二羟甲基丙酸及甲基丙烯酸 -β-羟乙酯合成了非扩链型和扩链型光固化聚氨酯丙烯酸酯 ( PUA) ,产物经叔胺中和后可以自乳化形式分散于水中。考察了聚乙二醇分子量PUA中羧基含量等因素对 PUA分散液表面张力及流变性的影响 ,扩链型 PUA具有较大的触变性 ,光聚合转化率明显高于非扩链型 PUA,羧基含量增加对光聚合有一定阻碍作用。高分子量 PEG促进 PUA固化膜中软、硬段相区的分离 ,扩链有助于抑制相分离。

Conventional and chain-extended UV-curable waterborne polyurethane-acrylate (PUA) ionomer were prepared from diisocyanate,polyethylene glycol(PEG) ,dimethylol- propionic acid(DMPA) ,hydroxyethyl methacrylate(HEMA) . The two kinds of PUA prepolymer could be easily dispersed in water in the form of self-emulsified latex after the carboxyl group at- taching to the backbone of PUA was neutralized with tertiary amine.The effects of M n of PEG, carboxyl content on the interfacial tension and rheological behavior of PUA dispersions were in- vestigated. The chain-extended PUA prepolymer could photopolymerize to a greater extent than conventional one as indicated by differential photocalorimetry.The differential scanning calorime- try(DSC) analysis for photocured films from PUA dispersions suggested that higher M n of PEG would provoke phase separation phase mixing between soft and hard segment phases.