采用阴离子开环聚合法制备超支化聚缩水甘油(HPG),基于“巯基-烯基”点击反应,以十二烷基硫醇(DS)修饰超支化聚缩水甘油(HPG)分子以获得超支化分子配体DSHPG,以DSHPG为稳定剂和表面修饰剂制备亲油性纳米银(Ag@DSHPG)。通过核磁共振(NMR)和傅里叶红外光谱(FT-IR)对DSHPG分子结构进行表征,采用透射电镜(TEM)、X射线衍射(XRD)和热重分析(TG)等手段对Ag@DSHPG进行表征。结果表明:50℃制备的纳米银平均粒径为3.94nm,粒径分布均匀。通过紫外-可见吸收光谱法(UV-Vis)研究纳米银在不同极性溶剂中的分散性和银纳米流体的稳定性。结果表明,DSHPG修饰的纳米银颗粒在非极性溶剂十氢萘中分散稳定性最好,以此为基液制备的银纳米流体在常温下可稳定储存30天以上,其热稳定性随受热温度的升高而逐渐降低,在100℃时纳米银可在基液中稳定分散超过8h。
The hyperbranched polyglycerol (HPG) was prepared by anionic ring-opening polymerization.HPG was modified with dodecanethiol (DS) based on the “decyl-alkenyl” click reaction to obtain the product DSHPG.Hydrophobic silver nanoparticles(Ag@DSHPG)were prepared with DSHPG as surface modifier.The molecular structures of DSHPG samples were characterized by nuclear magnetic resonance (NMR),and fourier transform infrared spectrometry (FT-IR).The Ag@DSHPG was characterized by transmission electron microscopy (TEM),X-ray diffractometry (XRD),and thermogravimetry (TGA).The Ag@DSHPG with an average size of 3.94nm prepared at 50℃ had uniform particle size.The dispersion ability in different fluids and the stability of Ag@DSHPG were characterized by ultraviolet-visible spectroscopic analyses (UV-Vis).It was shown that the DSHPG given the ability of silver nanoparticles to be well dispersed in decahydronaphthalene for more than 30 day at room temperature,and the thermal stability of the silver nanofluid decreased gradually with the rise of temperature.The silver nanoparticles can be dispersed in the base fluid for more than 8 hours at 100℃.
[1] Tringides M C,Jałochowski M,Bauer E.Quantum size effects in metallic nanostructures[J].Physics Today,2007,60(4):50-54.
[2] 翟秀静,张楠.纳米金属材料的研究进展[J].材料导报,1999,13(6):22-24.
[3] Zhang T Y,Xu W H.Surface effects on nanoindentation[J].Journal of Materials Research,2002,17(7):1715-1720.
[4] Wang J Q,Gu H W.Novel metal nanomaterials and their catalytic applications[J].Molecules,2015,20(9):17070-17092.
[5] Dai Y,Yu P,Zhang X,et al.Gold nanoparticles stabilized by amphiphilic hyperbranched polymers for catalytic reduction of 4-nitrophenol[J].Journal of Catalysis,2016,337:65-71.
[6] Singh M R.Application of metallic nanomaterials in nanomedicine[J].Advances in Experimental Medicine and Biology,2018,1052:83-102.
[7] 陈桂芳,梁志强,李根喜.纳米材料用于构建新型电化学生物传感器的研究进展[J].生物物理学报,2010,26(8):711-725.
[8] Shen Y,He G,Guo Y,et al.Modified hyperbranched polyglycerol as dispersant for size control and stabilization of gold nanoparticles in hydrocarbons[J].Nanoscale Research Letters,2017,12(1):525.
[9] 余娟,常桥稳,谢娇,等.贵金属纳米粒子的常见合成方法及应用[J].贵金属,2013,34(s1):155-160.
[10] 徐国园,李爱香,陈复强,等.聚合物包覆金属纳米粒子的制备研究进展[J].功能材料,2016,47(12):12029-12037.
[11] 陈志军,王雪兆,尹甲兴,等.硫醇链长对Au纳米粒子稳定性的影响[J].轻工学报,2013,28(2):40-43.
[12] Khoee S,Kavand A.A new procedure for preparation of polyethylene glycol-grafted magnetic iron oxide nanoparticles[J].Journal of Nanostructure in Chemistry,2014,4(3):111.
[13] Gao C,Yan D.Hyperbranched polymers:from synthesis to applications[J].Progress In Polymer Science,2004,29(3):183-275.
[14] 伊凤强,赵雄燕,孙占英.超支化聚合物的研究进展[J].塑料,2015,44(2):96-98.
[15] Sun F,Luo X,Kang L,et al.Synthesis of hyperbranched polymers and their applications in analytical chemistry[J].Polymer Chemistry,2015,6(8):1214-1225.
[16] 李爱香,李秋红,吕滋建,等.聚合物刷保护的贵金属纳米粒子的制备进展[J].高分子材料科学与工程,2015,31(3):185-190.
[17] Lowe A B.Thiol-ene “click” reactions and recent applications in polymer and materials synthesis:a first update[J].Polymer Chemistry,2014,5(17):4820-4870.
[18] Arslan M,Tasdelen M.Polymer nanocomposites via click chemistry reactions[J].Polymers,2017,9(10):499.
[19] Kainthan R K,Muliawan E B,Hatzikiriakos S G,et al.Synthesis,characterization,and viscoelastic properties of high molecular weight hyperbranched polyglycerols[J].Macromolecules,2006,39(22):7708-7717.
基金资助
国家自然科学基金(21603193);河南省科技攻关计划项目(172102210546);郑州轻工业学院博士启动基金(2015BSJJ045)