纤维素基纳米稀土发光复合材料的制备及发光性能研究

发布时间：2018-06-21 19:37

  本文选题：CMC/Tb纳米复合物 + HPCMC/Tb纳米复合物　； 参考：《华南理工大学》2015年硕士论文

【摘要】：稀土金属是宝贵的战略资源,而稀土纳米材料更具有广泛的工业应用。利用环境友好的生物质资源制备发光性能良好的稀土纳米发光材料,不但具有实现生物质资源高值化利用的意义,而且符合现代绿色化学的发展需求。本论文利用水浴和微波辅助两种不同的加热方式,使用环境友好的羧甲基纤维素(CMC)、羟丙基羧甲基纤维素(HPCMC)与Tb3+进行化学反应,通过设计和控制反应体系的实验条件,成功地合成发射较强荧光的CMC/Tb和HPCMC/Tb纳米复合物。通过傅里叶红外光谱(FT-IR)、X-射线光电子能谱(XPS)分析其分子化学结构;扫描电镜(SEM)分析其形貌结构;广角X射线衍射(WAXD)和透射电镜(TEM)分析其结晶结构;紫外吸收光谱(UV-Vis)和荧光光谱(PL)分析其对光的吸收能力及荧光性能;热重分析(TG-DSC)分析其热稳定性质,得出主要结论如下:1.水浴和微波辅助加热下,Tb3+与CMC、HPCMC分子链上的-COO-、-OH以及-COC中的O原子分别通过离子键和共价键键合形成CMC/Tb、HPCMC/Tb复合物,其粒子尺寸可达到纳米级。2.CMC、HPCMC作为主要的光能量吸收体,并能有效敏化Tb3+离子,使其具有窄的5D4→7F6(489 nm),5D4→7F5(545 nm),5D4→7F4(584 nm)和5D4→7F3(619 nm)电子轨道跃迁特征峰,其最强的5D4→7F5跃迁绿色荧光发射特征峰的半峰宽小于10 nm。3.CMC/Tb纳米复合物的结构和荧光性能均受到pH值、反应物比例和反应时间的影响。在本论文实验范围内,水浴加热时,最佳合成条件是:pH=8、反应物比例为CMC:Tb=5:1(wt:wt)、反应时间为30 min、反应温度为70℃。微波辅助加热时,最佳合成条件是:p H=8、反应物比例为CMC:Tb=1.65:1(wt:wt)、反应时间为10 min、反应温度为70℃。4 HPCMC/Tb纳米复合物的结构和荧光性能同样受到pH值和反应时间的影响。水浴加热时,最佳的合成条件是:pH=8、反应物比例为HPCMC:Tb=20:1(wt:wt)、反应时间为60 min、反应温度为70℃。微波辅助加热时,最佳的合成条件是:pH=7、反应物比例为HPCMC:Tb=20:1(wt:wt)、反应时间为15 min、反应温度为70℃。此条件下合成的CMC/Tb、HPCMC/Tb纳米复合物具有粒径小、分布均匀、荧光强度大、热稳定性高等特点。5.高pH值下,微波辅助比水浴加热方式更能提高CMC羧基与Tb3+反应能力,改变介观形貌结构,提高产物的荧光强度;HPCMC自身较长的侧链比CMC更容易与Tb3+反应,而且较强的结晶结构更能提高产物的荧光强度。
[Abstract]:Rare earth metals are valuable strategic resources, and rare earth nanomaterials are widely used in industry. The preparation of rare earth nano-luminescent materials with good luminescence performance by using environment-friendly biomass resources not only has the significance of realizing the high value utilization of biomass resources, but also meets the needs of the development of modern green chemistry. In this paper, water bath and microwave-assisted heating were used to react with Tb3 by using the environmentally friendly carboxymethyl cellulose (CMC) and hydroxypropyl carboxymethyl cellulose (HPCMC). The experimental conditions of the reaction system were designed and controlled. CMC / TB / HPCMC / TB nanocomposites with high fluorescence emission were successfully synthesized. Its molecular chemical structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and scanning electron microscopy (SEM), and its crystalline structure was analyzed by WAXD and TEM (TEM). UV absorption spectra and fluorescence spectra were used to analyze their absorption ability and fluorescence properties. TG-DSCs were used to analyze their thermal stability. The main conclusions were as follows: 1. In water bath and microwave assisted heating, the CMC / Tb3 / TB complex was formed by ionic bonding and covalent bonding with the -COO-OH-OH and O-COC atoms in the molecular chain of CMC / HPCMC, respectively. The particle size of the CMC / TbCHPCMC / TB complex can reach nanometer level. 2. CMCHPCMC is used as the main absorber of light energy. The Tb3 ion can be sensitized effectively and has the characteristic peaks of the electron orbital transition of 5D4 + 7F6O489nmmH4 / 7F5D4 / 545nm / 545Nm / 5D4 and 5D4 / 7F3 / 619nm), respectively, and can be used to sensitize the Tb3 ion effectively, so that it has the characteristic peaks of electron orbital transition. The structure and fluorescence properties of the strongest green fluorescence emission characteristic peak of 5D4 / 7F5 transition are affected by pH value, reactant ratio and reaction time. The half-width of the peak width is less than 10nm.3.CMC / TB nanocomposite. In this paper, when heated in water bath, the optimum synthesis conditions are: 1: pH8, CMC: Tb5: 1: wt1: wt1, reaction time 30 min, reaction temperature 70 鈩，

本文编号：2049781