| 簡 介： |
Isophorone diisocyanate was reacted with bis(3-(1-methoxy-2- hydroxypropoxy) propyl) terminated polysiloxanes (PMTS) to input cyanate group in polysiloxanes molecular chains. Polypropylene and dimethylol propanic acid were then added to
get polysiloxane modified polyurethane (PSU) prepolymer. Dihydroxyl glyceryl methacrylate was then used as coupling agent to react with PSU prepolymers to introduce vinyl groups with objective to conduct graft-polymerization with acrylics in a subsequent step, and so that to get polysiloxane acrylic modified polyurethane (PSU-AC) latexes. The results showed that the particle size, surface tension and viscosity of the PSU-AC latexes were kept constant with increase in PMTS content, while contact angle of
PSU-AC film with water increased. When PMTS was less than 10% (based on PSU), PSU-AC loss tanδ exhibited two peaks with varying temperature. When PMTS content was higher than 10%, the loss tanδ exhibited just one peak, but it was much wider than the two observed with PMTS below 10%. Without PMTS, acrylics polyurethane film became white after it was immerged in water for 11 h, and this whitening effect was observed upon 36 h immersion in water when 2.5% and 5.0% of PMTS were incorporated in PSU-AC. While when PMTS was more than 7.5%, PSU-AC film showed no visible change after immersion in water for 15 days. |
