Polymer / Sio <sub> 2 </ Sub> In Situ Composites Prepared By Materials And Inorganic Particle Growth Process,

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.