含羧基纤维素衍生物/稀土金属离子纳米复合物的性质

Properties of Carboxyl-Containing Cellulose Derivatives/Rare Earth Ions Nanocomposites

制备了CMC/Eu(Ⅲ)、CMC/Tb(Ⅲ)、HPCMC/Eu(Ⅲ)、HPCMC/Tb(Ⅲ)纳米复合物,通过XPS、UV-Vis、流变学检测及TG-DSC研究了产物的"天线效应"、荧光性质、静态/动态流变性质以及热性质.XPS结果表明,Eu^(3+)、Tb^(3+)与CMC、HPCMC均生成Ln(Ⅲ)—O,而且产物的紫外吸收与其激发光谱有重叠,证明纤维素衍生物所吸收的能量可以成功地转移到稀土金属,使之发光;流变学性能研究结果表明,前述4种纳米复合物溶液均为假塑性流体,黏流活化能分别为1.5964、2.5193、1.6047和1.4218 k J/mol,其黏度对温度具有依赖性;溶液的储能模量和损耗模量均随角频率的增大而增大;纳米复合物与CMC-Na、HPCMC-Na有相似的热性质,且HPCMC侧链更易与水通过氢键结合.

CMC/Eu（ Ⅲ）,CMC/Tb（ Ⅲ）,HPCMC/Eu（ Ⅲ）,HPCMC/Tb（ Ⅲ） nanocomplexes were prepared,and the ＂antenna effect＂,fluorescence properties,static and dynamic rheological properties and thermal properties of the products were investigated by means of XPS,UV-Vis,rheological detection and TG-DSC. XPS results show that Ln（ Ⅲ） —O is formed in all the products of Eu^（3＋）and Tb^（3＋）reacting with CMC and HPCMC,and the UV absorption of the products overlaps its excitation spectrum,which proves that the energy absorbed by cellulose derivatives can be successfully transferred to a rare earth metal to make it light. The results of the rheological properties of the nanocomplexes show that the solutions of all nanocomplexes are pseudo-complex,and the flow activation energy of the four kinds of nanocomplexes are 1. 596 4,2. 519 3,1. 604 7 and 1. 421 8 k J/mol respectively,suggesting that the viscosity is dependent on temperature. In addition,the storage modulus and loss modulus of the solution grow up with an increase of the angular frequency; the thermal properties of the nanocomplexes are similar to those of CMC-Na and HPCMC-Na,and the side chains on HPCMC are more readily associated with water through hydrogen bonding.