九州大学学術情報リポジトリ
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バイオポリマー/イモゴライトナノクレイ複合材料の 設計と特性評価
李, 林林
https://doi.org/10.15017/4060124
出版情報：Kyushu University, 2019, 博士（工学）, 課程博士 バージョン：
権利関係：
（様式２）
氏 名 ： 李 林林
論 文 名 ：
Design and Characterization of Hybrid Materials of Biopolymer/Imogolite Nanoclay
（バイオポリマー/イモゴライトナノクレイ複合材料の設計と 特性評価）
区 分 ：甲
論 文 内 容 の 要 旨
Owing to the increasing awareness of environment-protection, hybrid materials that are pollution-free are desirable. Under this background, in this thesis, natural biopolymers and natural aluminum silicate nanoclay were used to study the interactions and properties of hybrid materials. Specially, cellulose nanocrystal (CNC), sacran and cellulose fibers (CFs) are adopted to prepare hybrid films with imogolite due to their excellent properties such as good mechanical performance and transparency. The main objective of the study is to fabricate stable and pollution-free hybrid materials.
We focused on nanocelluose/imogolite, sacran/imogolite hybrid materials and fabricated them by facile methods, including solvent casting and layer-by-layer assembly. We mainly studied the structures and properties of the hybrid materials. We hope this study could provide one of the options of fabricating biopolymer hybrid materials, knowing more about their properties for better usage of these materials.
Chapter 2 describes phosphorylated cellulose nanocrystal (P-CNC)/imogolite nanotube hybrid thin film that was fabricated by spin-assisted LBL assembly. The first step is phosphorylation of CNC to introduce phosphate groups on CNC surface for the enhanced interaction with imogolite. Structure of the P-CNC/imogolite thin film was characterized by atomic force microscopy, scanning electron microscopy, X-ray diffraction and grazing incidence wide angle X-ray diffraction. The result revealed that thickness of hybrid film increased linearly with the increment of the P-CNC/imogolite bilayer. Benefitting from the strong affinity between the phosphate group of P-CNC and the Al-OH group of imogolite, the thin films were quite stable in water within a wide range of pH values, compared with the deterioration of the CNC/imogolite film under the same soaking conditions.
Chapter 3 describes a hybrid free-standing film obtained by alternative LBL assembly of sacran and imogolite. Same with P-CNC/imogolite film, thickness of sacran/imogolite film increased linearly with the increment of bilayers owing to the negatively charged surface of sacran, and the positively charged external surface of imogolite. Moreover, thickness of each bilayer is much larger than that of P-CNC/imogolite bilayer. UV-vis test indicated that this LBL film has better transparency than the sacran/imogolite blend film. Surface morphology of the
sacran/imogolite LBL film showed that the thin film was uniform in macro-meter scale, and plenty of imogolite nanotubes were absorbed onto a sacran layer. The structure and the mechanical property of the films were also investigated. The mechanical performance of the sacran/imogolite LBL film is superior to that of neat sacran film, and sacran/imogolite blend film.
Chapter 4 describes hybrid materials composed of cellulose fibers (CFs) and imogolite nanotubes. The structure, density and properties of the hybrid materials were mainly studied.
For that, the hybrid materials were characterized by SEM, AFM, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), rheological test, and wideangle X-ray diffraction (WAXD). The tensile test demonstrated that the mechanical properties of the hybrid films were considerably improved by the addition of imogolite up to 1 wt%; meanwhile, the thermal-mechanical properties of the hybrid film were also enhanced.
Chapter 5 gives a summary of the whole thesis work, and the outlook of the biopolymers/clay hybrid materials.
