A Study Of Physical Chemical And Luminous Properties Of SBA-15 Composite Materials

SBA-15 molecular sieve has been successfully synthesized by a microwave-assisted hydrothermal synthesis(MAHS) method and hydrothermal synthesis method,using poly (ethylene glycol)-block-poly(propyl glycol)-block-poly(ethylene glycol)(EG20PG40EG20) as a template.The synthesis of SBA-15 molecular sieve by MAHS method only needs 125 min and synthesis is more than 34 times faster than that by the conventional hydrothermal synthesis method.Powder X-ray diffraction(XRD),Fourier transform infrared spectroscopy (FT-IR),nitrogen adsorption-desorption technique,transmission electron microscopy(TEM) and scanning electron microscopy(SEM) were used to characterize the materials.The powder X-ray diffraction results showed that the structures of the SBA-15 molecular sieves correspond to that by the hydrothermal method.The nitrogen adsorption-desorption results showed that the average pore diameter of the SBA-15 molecular sieve synthesized by MAHS method was 6.49 for microwave-assisted synthesis of SBA-15 molecular sieve in 5 min(FS) sample and 7.40 nm for microwave-assisted synthesis of SBA-15 molecular sieve in 30 min(TS) sample.The scanning electron microscopy results showed that the primary particles of the samples presented acicular crystals,crystals longness was 100μm for FS sample and 64μm for TS sample,crystals diameter was 4.5μm for FS sample and 3.6μm for TS sample,respectively.The use of microwave radiation can transfer energy uniformly and quickly,and complete the syntheses of SBA-15 molecular sieve within a short time.Lanthanum oxide was incorporated into SBA-15 mesoporous molecular sieve via liquid-phase grafting,thermal diffusion,and microwave-assisted synthesis methods.A series of characterizations including powder X-ray diffraction(XRD),chemical analysis,Fourier transform infrared spectroscopy(FT-IR),nitrogen adsorption-desorption technique, transmission electron microscopy(TEM),scanning electron microscopy(SEM),solid state diffuse reflection absorption spectra,fluorescence spectra and photoluminescence(PL) spectra were used to characterize the prepared materials.The results showed that in the prepared host-guest(SBA-15)-La₂O₃ materials the frameworks of the host molecular sieve kept intact and its structures were kept highly ordered.The incorporated lanthanum oxide located inside the pores of the SBA-15.The prepared host-guest composite materials showed the properties of luminescence.From the solid state diffuse reflection absorption spectra of the host-guest(SBA-15)-La2O₃ materials,the blue-shift phenomenon of the spectra can be ascribed to the stereoconfinement of the pores of the SBA-15 and quantum size effect is clearly associated with the nanosize of La₂O₃.The solid state diffuse reflectance absorption spectra prove that La₂O₃ has been successfully trapped in the channels of the SBA-15 molecular sieve.From the luminescence spectra of the materials,there are no phenomena of luminescence of the host SBA-15 molecular sieve.However,for the prepared (SBA-15)-La₂O₃ composite materials,the phenomena of luminescence appeared.The luminescent intensities of the(SBA-15)-La₂O₃ materials samples are about 2 times of bulk La₂O₃.They have the potentiality as luminescent materials.From the PL spectra of the samples,the luminescent intensities of SS(Solid thermal diffusion),MWSS(Microwave La₂O₃ diffusion),MWNS(Microwave La(NO₃)₃ diffusion) and LS(Liquid phase grafting) samples are much higher than those of bulk La₂O₃ and the mechanical mixture of SBA-15 and La₂O₃(5 wt%).For the peaks which locate near 532 nm,the luminescent intensities of SS sample is about 8 times of bulk La₂O₃ and 11 times of the mechanical mixture of SBA-15 and La₂O₃(5 wt%),the luminescent intensities of MWSS sample is about 6 times of bulk La₂O₃ and 8 times of the mechanical mixture of SBA-15 and La₂O₃(5 wt%),the luminescent intensities of MWNS sample is about 3 times of bulk La₂O₃ and 4 times of the mechanical mixture of SBA-15 and La₂O₃(5 wt%),the luminescent intensities of LS sample is about 5 times of bulk La₂O₃ and 7 times of the mechanical mixture of SBA-15 and La₂O₃ (5 wt%),respectively.In this study,mesoporous SBA-15 molecular sieve was prepared to evaluate its application as nimodipine drug delivery system.The nimodipine was doped inside the pores of SBA-15 by contacting a solution of the nimodipine in an appropriate solvent with the porous solid,and the drug release process from the matrix into a simulated body fluid(SBF) solution has been studied.The results showed that the release effect of nimodipine was 50% in 12 h～13 h,100%in 24 h²5 h,and followed by a very slow release pattern.The surface of SBA-15 was functionalized with phenyltrimethoxysilane or trimethylchlorosilane before calcination.Chemical analysis,powder X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR),nitrogen adsorption-desorption technique,transmission electron microscopy(TEM) and scanning electron microscopy(SEM) were used to characterize the materials.The approaches described in this thesis provide methods for carry of nimodipine and improve effect of nimodipine.