Preparation And Properties Of β-Cyclodextrin Polymer-Titanium/Zirconium Dioxide Inorganic-organic Hybrid Materials

In recent years, the inorganic-organic hybrid materials are used widely in electricity, magnetics, and optics fields and so on, because of its interesting optical, magnetic, catalytic and thermal steady properties. One of the most versatile methods for preparation of hybrid material is sol-gel processing which allows the formation of the organic entities easily controlled starting from molecular precursors in the normal temperature and simple reactivity condition. Cyclodextrin (CD) as an organic substance with particular function can selectively form inclusion complexes with many organic, inorganic and biological molecules. The β-cyclodextrin polymer (β-CDP) has more superior capabilities to β-CD. The main applications of β-CDP are related to chromatographic techniques, catalysts, absorbents and environment protection. Titanium dioxide has become the favorite object for degradation of the organic contamination owing to its unique photocatalytic property. In addition, the zirconia is one of the most important ceramics, which has unique physical and chemical properties that allow it to be used as oxygen sensor, catalyst support, corrosive coating and as inclusion in composites for increasing toughness. So it can be expected to obtain better materials with high catalysis and stability from the hybrid material of β-cyclodextrin polymer and titania or zirconia. In this thesis, our research is mainly focused on the following three parts:1. The copolymer P(CD-co-AA) (I) was synthesized by β-CD, 3-bromoprop-1-ene and acrylic acid. Then, the hybrid materials P(CD-co-AA)/TiO₂, with existing the strong action between TiO₂ phase and the polymer matrix in the hybrids, were prepared by sol-gel process using Ti(OC₄H₉)₄ as the precursor. The content of cyclodextrin in the copolymer P(CD-co-AA) (I) was 92%, which was detected by the phenol-sulfuric acid method. According to the fluorescent analysis, the supermolecular behavior between P(CD-co-AA) (I) and naphthalene can be observed. The results of the solvent-extracted hybrid materials and FTIR analysis prove the evidence of the chemical bonds between TiO₂ and the polymer matrix in the hybrids. And also the hybrid materials were characterized by XRD, SEM and TGA, indicating that the TiO₂ phase and polymer matrix have been well dispersed evenly with each other. At the same time, it was found that the content of TiO₂ influenced on the structure and properties of the hybrid materials. The most excellent thermal stability and the intermolecular regularity hybridmaterials can be obtained when the content of TiO2 was 60% (w) in the hybrid.2. The photocatalytic properties of the hybrid, P(CD-co-AA)/TiO2, were studied using methyl orange as an organic contamination. The hybrid materials exhibit higher photocatalytic activity than T1O2 colloid. Taking the P(CD-co-AA) /TiC>2 (60%) as a example, we found that the several basic features influenced the photocatalytic activity of P(CD-co-AA)/TiO2, such as catalyst amount, initial concentration and pH value of the dye solution, based on the degradation of methyl orange under UV-light irradiation. The results show that the best photocatalytic activity of P(CD-co-AA)/TiO2 (60%) can be obtained when the amount of P(CD-co-AA)/TiC<2 (60%) is 0.04 g and the initial concentration and pH value of methyl orange are 4 mg/L and 2, respectively.3. The 6-O-allyl-/?-CD was synthesized by /?-CD and 3-bromoprop-l-ene, and the copolymer P(CD-co-AA) (II) was synthesized by copolymerization between 6-O-allyl-/?-CD and acrylic acid (AA). Then the hybrid materials, P(CD-co-AA)/ZrO2, which contain the chemical bond between ZrC>2 phase and the polymer matrix in the hybrids, were prepared by sol-gel process using Zr(OC4H9)4 as the precursor. The 6-O-allyl-/?-CD was characterized by FT-IR and 13C NMR spectra showing that the all 6-OHs of the CD were substituted by allyl. The content of cyclodextrin was 92% in the copolymer P(CD-co-AA) (II), which was detected by phenol-sulfuric acid method. The supermolecular behavior of the 6-O-allyl-/?-CD and the P(CD-co-AA) (II) was explored with fluorescent analysis preliminarily by including naphthalene. The results show that both of them form 1:1 inclusion complex and the including constants are K = 500 ± 15 mL/g and K = 1250 ± 50 mL/g, respectively. Furthermore, the study of P(CD-co-AA)/ZrC>2 by solvent extraction and FTIR analysis, shows that there is indeed evidence of the chemical bond between the ZrC>2 phase and the polymer matrix in the hybrids and displays that the ZrC>2 phase and polymer matrix were well dispersed evenly with each other when characterized by XRD, SEM and TGA. Meanwhile, it was found that the ZrC>2 content influenced the structure of the hybrid materials. The hybrid materials acquired more excellent the intermolecular regularity when the content of ZrO2 was 50% (w) in the hybrid.