Abstract:

In the presence of mercaptoethanol as chaintransfer agent, hydroxylterminated polyacrylate(PA) with a certain molecular mass was synthesized by solution freeradical polymerization of butyl acrylate(BA) and methyl methacrylate(MMA). The PA-PU-PA hybrid emulsion was obtained by reacting PA with polyurethane(PU) prepolymer in water. FTIR and ¹H NMR results of the copolymer chain structure show that when PU/PA mass ratio declined, the acrylic content in the copolymer increased and the role of hydrogen bonds between PU soft and hard segment weakened. The composite particles had homogeneous coreshell structure in TEM photograph. Waterproof and heat resistant performance of the modified latex film were improved with the decrease of PU/PA mass ratio. Water absorption of the modified film dropped from 25% to 5% and the maximum mass loss temperature was increased from 369 ℃ to 432 ℃.

Key words: polyacrylate, aqueous polyurethane, modifying, multi-block copolymerization