聚合物/SiO₂材料的原位复合法制备及无机粒子生长过程研究

【作者】 冯庆；

【导师】 潘春跃；

【作者基本信息】 中南大学 ， 有机化学， 2007， 硕士

【摘要】 本文首先以原位复合法制备复合固态聚合物电解质中无机粒子生长过程为研究对象，重点研究聚合物与锂盐对TEOS水解反应与SiO₂粒子生长的影响。采用激光粒度分布仪、高分辨透射电镜（HTEM）、扫描电镜（SEM）、热重（TG）、红外（IR）、X-射线衍射（XRD）、紫外-可见光分光光度计等手段，对原位复合法所得样品进行了表征与分析，并探讨了原位生成SiO₂的机理。SEM、HTEM和粒径分析结果表明，加入高分子聚合物（PEG和PEO）后，聚合物包覆在了SiO₂粒子的表面，限制了SiO₂粒子的长大。酸催化下，SiO₂粒子形状不甚规则，粒径约为100nm；碱催化下，SiO₂粒子呈球状，粒径为50nm左右；从XRD结果可知，在PEO中添加SiO₂后，体系的结晶度由原来的66.05％降低到了12.76％；加入锂盐，有利于SiO₂的结晶。其次，采用IR、TEM、AFM、TG、XPS和透光率测试对原位复合法制备的PMMA／SiO₂，P（MMA-MPTMS）／SiO₂杂化材料的结构、粒子分布、形貌、热稳定性能、表面化学组成和光学性能进行了分析。IR分析表明，P（MMA-MPTMS）／SiO₂中形成SiO₂无机网络，其中的C=O与无机网络中未完全缩合的Si-OH之间形成了氢键作用。从TEM和AFM可知，P（MMA-MPTMS）／SiO₂中两相问比较模糊，未出现明显相分离，粒子间没有明显的团聚，比较均匀地分散于P（MMA-MPTMS）基体，且样品表面十分平整光滑，SiO₂的粒径小于10nm。TG分析表明，偶联剂MPTMS的加入，提高了P（MMA-MPTMS）／SiO₂的热稳定性能。透光性测试表明，偶联剂MPTMS共聚改性后的杂化材料透光性明显高于PMMA／SiO₂，透光率可达95％。从XPS分析可知，P（MMA-MPTMS）／SiO₂样品中存在SiO₂无机网络结构。最后采用原位复合法制备了PMMA／LiClO₄／SiO₂和P（MMA-MPTMS）／LiClO₄／SiO₂复合聚合物电解质，通过TG、XPS、交流阻抗等技术对所制备的CSPE材料的结构和性能进行了表征与分析，探讨了原位复合无机粒子和MPTMS共聚改性PMMA对CSPE材料导电性能的增强机制。TG分析表明，添加无机粒子SiO₂和MPTMS可以提高聚合物电解质的热稳定性。XPS分析表明，聚合物电解质中存在SiO₂无机网络结构。当O／Li=8时，PMMA／LiCl₄／SiO₂电导率达到最大值。添加SiO₂能够提高PMMA基聚合物电解质的离子电导率，且电导率随着SiO₂含量的增加先不断增大，当SiO₂含量达到10wt％时，两体系的电导率均达到最大值，继续增加SiO₂含量，电导率反而减小。无论SiO₂含量的高低，MPTMS改性PMMA基聚电解质体系电导率都比未改性PMMA的要低。更多还原

【Abstract】 Firstly, In order to discuss the factors which affect the process ofSiO₂ particle growth in the composite polymer electrolyte, theinteraction between the polymer, the lithium salt, the catalyst areinspected for emphases. The growth of the nano-meter particle SiO₂ arestudied by laser particle-size distribution meter, transmission electronmicroscope （TEM）, scanning electron microscope （SEM）, X-Raydiffracts （XRD）, Ultraviolet-Visible light spectrophotometer and so on.SEM, TEM and the particle size analysis results indicate that, thepolymer chains enwraped SiO₂ particle surface, which limited the SiO₂partical coarsening after addition of the polymer （PEG and PEO）. In theacid catalysis, SiO₂ particles are not really regular and the size isapproximately 100nm. In the basic catalysis, the SiO₂ particles arespherically, the average particle size is about 50nm. It can be seen fromthe XRD result that the system crystallinity reduced from 66.05% to12.76% after adding SiO₂ into polymer.Secondly, the structure, morphology, particle sizes, thermalperformance and optical transparency of PMMA/SiO₂ andP（MMA-MPTMS）/SiO₂ hybrid material prepared through the blendingin-situ was examined by IR spectra, XPS, TEM, AFM, TG and UV-Visspectra.IR shows that the silica networks are composed of Si-O-Sibackbones. The formation of hydrogen bond between the silica and thecarbonyl of P（MMA-MPTMS） were observed. TEM and AFM show thatthe dimensions of the particles are much smaller than in the hybridwithout MPTMS, about 10nm, the interface between the SiO₂ particlesand the polymer matrix are very illegibility in P（MMA-MPTMS）/SiO₂.The P（MMA-MPTMS）/SiO₂ hybrids has a smoother surface and no phaseseparation is observed in it. TG shows that the thermal stability of hybridsis improved when adding MPTMS. The transmittance of theP（MMA-MPTMS）/SiO₂ was above 95%. The results of XPS show thatformation of the three-dimensional Si-O-Si network in the P（MMA-MPTMS）/SiO₂.Lastly, PMMA/LiClO₄/SiO₂ and P（MMA-MPTMS）/LiClO₄/SiO₂polymer electrolytes were prepared by the method of blending in-situ.The thermal performance, structure and ionic conductivity of the CSPEwere investigated by TG, XPS and A.C.impedance spectroscopy. Themechanism of conductivity enhancement was speculated on the basis ofexperiment results.TG shows that the thermal stability of polymer electrolyte isimproved when adding SiO₂ and MPTMS. The Si-O-Si networksstructure of SiO₂ is observed, the oxygen and carbon of binding energy ofthe polymer electrolyte have improved when the adding LiClO₄ fromXPS. A.C. impedance spectra of CSPE shows that the conductivity attainsthe maximum value, when O/Li is eight in the PMMA/LiClO₄/SiO₂, andis increased obviously by addition of SiO₂ at room temperature. Theconductivity of PMMA/LiClO₄/SiO₂ and P（MMA-MPTMS）/LiClO₄/SiO₂increases with increasing of the SiO₂ and attains a maximum value whenthe SiO₂ content is at 10wt%. Subsequently, the conductivity decreaseswith further increasing the SiO₂ content. The conductivity of polymerelectrolyte is decreased after the addition of MPTMS.更多还原