超支化聚缩水甘油修饰亲油性纳米银的制备及稳定性研究

Preparation and stability of hyperbranched polyglycidol modified lipophilic silver nanoparticle

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 3.94 nm prepared at50℃ 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℃.