辐射活性接枝聚合制备双重响应性还原氧化石墨烯材料  

Dual-responsive reduced graphene oxides prepared by radiation-initiated living radical grafting polymerization

作　　者：翁汉钦 张宝莹 王璇 肖鑫 山下真一 汪谟贞[2] 葛学武[2] WENG Hanqin;ZHANG Baoying;WANG Xuan;XIAO Xin;YAMASHITA Shinichi;WANG Mozhen;GE Xuewu(Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-sen University,Zhuhai 519082,China;Key Laboratory of Precision and Intelligent Chemistry,Department of Polymer Science and Engineering,University of Science and Technology of China,Hefei 230026,China;Nuclear Professional School,School of Engineering,The University of Tokyo,2-22 Shirakata-shirane,Tokai-mura,Naka-gun,Ibaraki 319-1188,Japan)

机构地区：[1]中山大学中法核工程与技术学院,珠海519082 [2]精准智能化学重点实验室中国科学技术大学高分子科学与工程系,合肥230026 [3]日本东京大学工学院,茨城319-1188

出　　处：《辐射研究与辐射工艺学报》2024年第6期93-103,共11页Journal of Radiation Research and Radiation Processing

基　　金：国家自然科学基金(51803205);中国国家留学基金委(201906345006)。

摘　　要：本研究通过辐射可逆加成?断裂链转移聚合在氧化石墨烯(GO)表面接枝了具有温度响应性的聚(N-异丙基丙烯酰胺)(PNIPAAm)。Raman光谱和X射线光电子能谱分析表明,GO在水溶液中共辐射接枝时会被同步还原。吸收剂量为1.8~14.4 kGy时,接枝了PNIPAAm的还原氧化石墨烯(rGO-g-PNIPAAm)还原程度和接枝率均随吸收剂量而增加。脉冲辐解研究证明,NIPAAm与水辐解产生的水合电子(e_(aq)^(-))和羟基自由基(OH)均会反应,反应速率常数分别为1.0×10^(10)L/(mol·s)和(4.3±0.2)×10^(9) L/(mol·s)。NIPAAm与OH反应在不饱和双键位置形成自由基,引发单体自由基加成聚合。而NIPAAm与e_(aq)^(-)的反应,不仅消耗了强还原性的e_(aq)^(-),还生成了还原性较弱的阴离子自由基中间产物,从而降低了r GO的还原程度。低还原程度的rGO表面残余羧基等含氧基团,赋予了rGO-g-PNIPAAm良好的p H响应性。辐射接枝的吸收剂量为3.6 kGy时,所制备的rGO-g-PNIPAAm具有优异的光热转换性能,较未接枝改性的GO提升30%。本工作为制备具有pH和温度双重响应性的光热转换材料提供了便捷、可控的方法。Temperature-responsive poly(N-isopropylacrylamide)(PNIPAAm)was grafted onto the surface of graphene oxide(GO)via reversible addition-fragmentation chain transfer polymerization initiated byγ-ray radiation.Raman spectroscopy and X-ray photoelectron spectroscopy analyses indicated that GO was reduced synchronously upon the radiation grafting polymerization of NIPAAm in an aqueous solution.A pulse radiolysis study demonstrated that NIPAAm reacted with both hydrated electrons(e_(aq)^(-))and hydroxyl radicals(OH)produced by water radiolysis of which the reaction rate constants were 1.0×10^(10) L/(mol∙s)and(4.3±0.2)×10^(9) L/(mol∙s),respectively.The addition reaction between NIPAAm and OH produces a radical at the unsaturated double bond of NIPAAm,which initiates the free radical polymerization of the monomers.Meanwhile,the reaction between NIPAAm and e_(aq)^(-)not only consumes strongly reductive e_(aq)^(-)but also produces weakly reductive radical anion intermediates,which decreases the reduction degree of rGO.The residual oxygen-containing groups on the surface of rGO with a low degree of reduction degree,such as carboxyl groups,endowed rGO-g-PNIPAAm with good pH responsiveness.Compared to pristine GO without PNIPAAm grafting,rGO-g-PNIPAAm which prepared with an absorbed dose of 3.6 kGy for radiation grafting polymerization exhibited a 30%higher photothermal conversion efficiency under near-infrared LASER irradiation.This study provides a convenient and controllable method for preparing photothermal conversion materials with pH and temperature dual responsiveness.

关 键 词：辐射接枝聚合 可逆加成-断裂链转移聚合 氧化石墨烯 N-异丙基丙烯酰胺 脉冲辐解 

分 类 号：TL13[核科学技术—核能科学]