【摘要】 合成了以Upy(2-ureido-4[1H]-pyrimidone)封端的超支化聚合物并研究其涂层材料性能.首先在哌嗪与三羟甲基丙烷三丙烯酸酯摩尔比2.25∶1条件下,合成了端仲胺基超支化聚(酯-胺)(HPEA),进而在仲胺基/异氰酸酯基官能团比1∶0.3、1∶0.4和1∶0.5下,通过HPEA与单异氰酸酯基甲基异胞嘧啶反应,合成了一系列带有Upy基元的改性超支化聚合物.由于Upy基元间形成了自识别四重氢键,改性聚合物比HPEA具有更高的玻璃化转变温度和热分解温度,并且改性聚合物涂层具有优良的力学性能,这表明分子间强氢键相互作用可有效改善超支化聚合物的性能.更多还原

【Abstract】 2-ureido-4[1H]-pyrimidone(Upy)telechelic hyperbranched polymers were prepared and their coating performances were investigated.First,a secondary amine terminated hyperbranched poly(ester-amine)(HPEA)was prepared from piperazine and trimethylolpropanetriacrylate at secondary amine/acrylate group ratio of 2.25/1.At secondary amine/isocyanate stoichiometric ratios of 1∶0.3,1∶0.4 and 1∶0.5,HPEA was further reacted with monoisocyanato methylisocytosine to give three modified hyperbranched polymers bearing terminal Upy units.Based on the 1H-NMR spectra of the modified polymers,the degree of modification was calculated,which agreed well with the feeding composition of the components.Due to the formation of self-complementary quadruple hydrogen bonding of Upy groups,the Upy modified polymers possessed improved glass transition temperature(T_g)and decomposing temperature(T_d)compared to HPEA.The coating materials of the modified polymers displayed good mechanical properties.The T_g,T_d and coating hardness became higher as increasing the Upy content.All the coatings possessed impact strength of 0.5 kg·m and flexibility of grade 7.This investigation demonstrated that hyperbranched polymers with improved performances could be obtained via incorporating strong hydrogen bonding,which is helpful for designing new dynamic materials.更多还原