ATRP法制备水溶性荧光温敏聚合物P(NIPAM-co-NBDAE)

以4-氯-7-硝基-2,1,3-苯并口恶唑(NBD-Cl)为原料,首先合成了荧光单体4-(2-丙烯酸胺乙基酯)-7-硝基-2,1,3-苯并口恶唑(NBDAE),然后以2-溴异丁酸乙酯(t-EBiB)为引发剂,CuCl/Me6TREN为催化剂,采用原子转移自由基聚合(ATRP),与温敏性单体N-异丙基丙烯酰胺(NIPAM)共聚,得到水溶性无规共聚物P(NIPAM-co-NBDAE)。对产物进行了1H-NMR,GPC,UV-Vis及荧光光谱仪(FL)表征。结果表明,成功制备了多分散系数小于1.20的窄分布荧光水溶性共聚物,并研究了该聚合物荧光强度随温度的变化。在PNIPAM的相变温度(30℃)以下,该聚合物在水溶液中荧光较弱;而在PNIPAM的相变温度(30℃)以上,该聚合物的荧光强度随PNIPAM疏水转变而显著增强。

The Preparation of Hydrophilic Temperature Sensitive Fluorescent Polymers P(NIPAM-co-NBDAE) by Atom Transfer Radical Polymerization

Firstly,A monomerized fluorescence molecular 4-(2-acryloyloxy-ethylamino)-7-nitro-2,1,3-benzoxadiazole(NBDAE) was prepared with NBD-Cl(4-Chloro7-nitro-2,1,3-benzoxadiazole) as raw material.Then,well-defined thermoresponsive water-soluble random copolymers,poly(N-isopropylacrylamide-co-NBDAE)(P(NIPAM-co-NBDAE)),were prepared by atom transfer radical polymerization (ATRP),with ethylbutyl-2-bromoiso-butyrate(t-EBiB) as initiator,and CuCl/Me6TREN as catalyst.The thermoresponsive copolymers were characterized by 1H-NMR,GPC,UV-Vis,and fluorescence measurement.The results indicate that the well-defined thermoresponsive hydrophilic copolymers are narrow molecular-weight distribution with the polydispersity index of less than 1.20.The copolymers possess good fluorescence performance.The phase transition temperature of PNIPAM is 30 ℃.At >30 ℃,The fluorescence emission of hydrophilic copolymers is weak.While at <30 ℃,the thermoresponsive hydrophilic copolymers exhibit 2.5 times increased fluorescence intensity.It is observed that temperature induce polymers collapse at elevated temperatures and can be employed as a novel temperature sensor.