| Agricultural biomass is a kind of abundant and renewable resource on the earth, which is often discarded and wasted a lot during manufacturing process. Agriculture biomass residue causes huge environmental pollution frequently due to improper disposal. As one of the ideal environmentally, friendly and clean materials, reuse of agriculture biomass is in accordance with the policy of green energy and low-carbon economy today. It is necessary to find perfect methods for high-value application of agricultural biomass. In this paper, bamboo shoot was selected as a representative of agricultural biomass and was prepared as cellulose-based hydrogel after a series of chemical treatments in Na OH/Urea system or ionic system. Next, the cellulose-based hydrogels were characterized, intending to analysis its microstructure, thermal properties, surface topography, chemical properties. In the aspect of application, swelling kinetics, enviromental response properties, mode molecule adsorption and release were also researched to reach the point of high-value use of agriculture biomass. The main content of this thesis is divided into three parts and main results as follows:(1) Novel hydrogel beads with cationic molecules adsorption abilities were prepared from bamboo carboxymethyl cellulose and κ-Carrageenan(κ-CN)by inverse suspension polymerization, using epichlorohydrin(ECH) as a crosslinking agent in alkaline surrounding. The structure of the prepared composite hydrogel was characterized(including FT-IR, TG, DSC, SEM) to understand its microstructure and properties. The hydrogel beads showed p H sensitive in swelling capacity due to its three-dimensional network structure and the electrostatic repulsion between negative charges from side chain groups. Swelling kinetics indicated that the hydrogel swelling behavior fitted to the Fickian diffusion model during the initial phase and complied with Schott Model during the whole swelling procedure. The hydrogel beads showed a high adsorption capacity for methylene blue(MB) in water and the adsorption capacity was affected by initial concentration and initial solution p H.(2)Bamboo carboxymethyl cellulose was extracted to prepare bamboo carboxymethyl cellulose/β-cyclodextrin hydrogel in Na OH/Urea system and cross-linked by epichlorohydrin(ECH), and characterization of this composite hydrogel(including FT-IR, TG, DSC, XRD, SEM) was performed in order to understand its microstructure and properties. The comprehensive swelling properties research of composite hydrogel in this chapter demonstrated that it possesses multiple environment response ability. Composite hydrogel showed sensitive to temperature because the intermolecular force between-COOH and-OH group on the polymer skeleton are changing according to environmental temperature. As a result of electrostatic repulsion from-COO- group varies in different p H buffers, composite hydrogel is sensitive to p H. Osmotic pressure differences in different salt solution are main reason that the composite hydrogel become ionic sensitive. Finally, the different polarity in organic solvent could cause different hydrogen bonding interaction with-OH group on cellulose skeleton. Sodium salicylate was used as the model drug to stimulate hydrogel adsorption and release experiment and results revealed the hydrogel could be used as enteric targeting drug delivery material.(3) The cationic etherifying agent CHPTAC(3-Chloro-2-hydroxypropyl trim-ethyl ammonium chloride) was used for cellulose modification and preparing quaternized cellulose(QC) in Na OH/IPA(Isopropyl alcohol) system. The DS(substitution degree) of QC with different molar ratio(CHPTAC to anhydroglucose unit) was determinate by elemental analysis range from 0.23 to 0.54, then the quaternized cellulose was characterized with FT-IR, 13C-NMR,TG, DSC, SEM and XRD methods to reveal structure and thermal properties. The quaternized cellulose(DS=0.54) was selected to blend with other polysaccharide to prepare hydrogel membrane in ionic liquic [Amim]Cl and [Bmim]Cl through technologies of film casting and freeze-thaw cycles. The hydrogel membrane was characterized and then its swelling properties was studied. The experiment revealed that the DS of the quaternized cellulose was changed according to molar ratio of CHPTAC to Cellulose-AGU; Quaternized cellulose in [Amim]Cl could be washed away after reaction and remained in [Bmim]Cl; It was found that QC may have hydrogen interactions with –OH group on hydrogel membrane, causing the absorption peak move to a lower position; The porogenic forming mechanism of hydrogel in Na OH/Urea system and hydrogel membrane in ionic system were found totally different, so the aperture of later was small(<0.2μm), limiting the swelling properties of hydrogel membrane. |
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