Preparation And Characterization Of A Novel Semirigid Thermoresponsive Random Copolymers

Due to reversible property changes in response to temperature, thermoresponsive polymers have attracted considerable research interests. However, the main-chains of these synthesized thennoresponsive polymers are mostly flexible and some of the thennoresponsive natural polymer and its derivatives segment with semi-rigid structure were difficult to molecular design and synthesis, all those hinder further research of these polymers.Mesogen-Jacketed Lliquid Crystal Polymer (MJLCP) is a typical semi-rigid synthesized polymer, but it is hardly water-solubled. Therefore, how to design and synthesize a novel polymer based on MJLCPs exhibited thennoresponsive property is very significance.Three novel thermoresponsive copolymers with the semi-rigid were synthesized via random copolymerization, and we focus on the body and solution properties.At first, synthesized random copolymer poly{{2.5-bis[(4-methoxyphenyl) oxycarbonyl]styrene}-co-bis-(N-hydroxyethylpyrrolidone)2-vinylterephthalate} (P(MPCS-co-NHEPVTA)), and investigated the body and solution properties of copolymers. The copolymers showed only one glass transition. And the results were consistent with our theory judgments:different MPCS content of copolymers have shown character of liquid crystalline. With the MPCS content increased copolymers the lower critical solution temperature (LCST) decreased evidently. The copolymers were almost insoluble in water when the content of MPCS more than 4%.Synthesized random copolymer poly{styrene-co-{2.5-bis[(4-methoxyphenyl) oxycarbonyl]styrene}(P(St-co-NHEPVTA)) and investigated the body and solution properties of copolymers. The copolymers showed only one glass transition. When the content of St more than 20%, the copolymer not showed liquid crystalline. With the St content increased copolymers LCST decreased evidently. The copolymers were almost insoluble in water When the content of PS more than 30%.Last, semi-rigid thennoresponsive copolymer poly{acrylamide-co-{2.5-bis [(4-methoxyphenyl)oxycarbonyl]styrene} (P(AM-co-NHEPVTA))have been successfully synthesized,and some properties in bulk were confirmed by GPC and DSC, at the same time, the thennoresponsive properties in solution were confirmed by visual observation. The results show that these polymers have the properties in bulk similar to MJLCPs, i.e., the just only one glass transition in these polymer. On the other hands, the liquid crystallinity didn't disappeared when the content of AM reached 70%. Moreover, with the increase in hydrophilic AM content, the LCST of copolymer would increase.All the experimential results show tha both liquid crystalline and thermoresponsive properties of the polymers could be contralled by adjusted the ratio of different hydrophilic and hydrophobic monomers. Furthermore, we would used these polymer to make some intelligent materials, and this work is under going.