【作者】 王霆；

【导师】 李斌；

【作者基本信息】 东北林业大学 ， 林产化学加工工程， 2011， 博士

【摘要】 环糊精作为第二代超分子主体化合物,具有范围极广的各类客体,已在医疗、食品、环境、化学分子组装等领域向世人展现出广泛的应用前景。将环糊精键合天然高分子来制备环糊精聚合物,既保留了环糊精的独特性质,又兼具天然高分子材料的良好性质如化学可调性、稳定性、环境友好性、可再生性,这给环糊精的应用提供了更广阔的空间。另外,纤维素作为我国东北地区最为重要的林业生物质资源之一,贮量极为丰富,但其综合利用率却不高,关于纤维素相关领域的研究、开发和应用一直受到了林业科学家的广泛关注和高度重视,已逐步成为生物质资源高效利用的热点和重点。本文以纤维素为主要原料,利用机械离心原理制备纤维素微球,在其表面采用无甲醛交联剂多元羧酸交联功能主体分子环糊精,同时利用化学原位还原技术搭载纳米银位点,得到的纤维素微球搭载无机／超分子复合功能材料。对酚酞探针分子检测环糊精技术,纤维素微球的制备及表征,环糊精主体功能分子在微球表面的接枝,β-环糊精对功能抑菌分子碘的包合、释放及应用、β-环糊精对芳香功能分子丁香酚的包合、释放及应用、纳米银位点搭载环糊精接枝纤维素微球的制备、表征及应用等科学问题进行了详细的探讨,具体研究内容和结果如下：1.采用改进的紫外分光光度法测定不同温度下酚酞分子与β-环糊精、2-羟丙基-β-环糊精、2,6-二甲基-β-环糊精生成包合物的结合常数。通过van’t Hoff方程对不同温度下的结合常数进行拟合,得到酚酞与三种环糊精包合的热力学参数(焓变、熵变)。结果表明：酚酞分子同三种环糊精的包合是受分子空间位阻影响的、自发的、以焓变为驱动的熵焓补偿过程。基于酚酞与环糊精的包合机制,建立了β-环糊精、2-羟丙基-β-环糊精、2,6-二甲基-β-环糊精的酚酞分子探针定量工作曲线。该探针技术定量三种环糊精的相对标准偏差小于0.6%,加标回收率在90-103%之间,体现出极好的精密度和准确性。2.以天然纤维素为主要原料,从纤维素的溶解、纤维素液滴的制备以及纤维素液滴的固化、再生等三个控制步骤来设计纤维素微球制备的新技术。探讨了纤维素黄原酸酯粘胶液粘度对微球产品制备的影响,并对影响纤维素黄原酸酯粘胶液粘度的主要因素进行了探索,总结出适宜的纤维微球制备工艺。此外,对微球的物理性质及表面形貌也进行相应的表征,结果表明：所制备的微球能够保持较好的圆度,它的堆积密度、振实密度、真实密度、压缩比以及空隙率分别为0.2780 g mL-1,0.2869 g mL-1,2.92%,0.4080g mL-1,29.9%,同天然纤维已经有了显著不同,是一种极具研究潜力的环保型载体材料。3.以纤维素微球为载体,采用1,2,3,4-丁烷四羧酸(BTCA)、柠檬酸(CA)、酒石酸(TA)等多元羧酸为交联剂,将β-环糊精接枝到纤维素微球表面,得到新型可具功能性的天然高分子微球载体材料。首次使用酚酞分子探针技术研究环糊精接枝纤维素微球功能材料表面的环糊精活性,并结合增重法对环糊精接枝纤维素微球功能材料的制备工艺进行详细探讨,得到交联温度、交联时间、不同多元羧酸所对应的催化剂组合、浸渍液中环糊精用量等制备条件对环糊精接枝的影响。此外,对2,6-二甲基-β-环糊精、2-羟丙基-β-环糊精在纤维素微球表明的接枝也进行了相应的研究,并同时制备出上述两种环糊精接枝的纤维素微球载体材料。4.利用紫外分光光度计,采用Hildebrand-Benesi方程,得到碘/β-环糊精包合物中碘与β-环糊精结合比为1：1,结合稳定常数为1268 L mol-1。研究并确定了碘/β-环糊精超分子包合物的制备工艺。设计碘量法定量固体包合物中碘的测定技术,并另行设计的高效液相色谱法对碘量法的测定结果进行验证,结果表明：碘量法定量包合态碘具有准确、方便及快速的特点。采用碘量法和热重分析仪,对固态碘/β-环糊精包合物的时间和热稳定性进行分析。通过对Avrami方程的拟合,得到包合物中碘含量的释放属于扩散控制的过程,室温下7天包合态碘的损失量少于5.8%,释放速率常数为5.78×x10-4 S-1。热重分析的结果证明：碘被β-环糊精包合后,不仅热稳定有所提高,而且也揭示了碘/β-环糊精包合物特殊的热释放行为。采用滤纸扩散法,以食品中常见的有害霉菌——黑曲霉为评价媒介,表征了包合物的抑菌能力。同时将碘分子作为功能化客体搭载入微球材料表面的β-环糊精中,得到可具杀菌功能性的纤维素微球材料。测定该材料中碘含量为3.1%,即该材料在抑菌领域可有潜在应用。5.采用冷冻干燥法制备固态丁香酚/β-环糊精主-客体包合物,采用x射线衍射仪、红外光谱仪表征包合物的成功制备。设计紫外分光光度法定量包合态的测定技术,并于25℃及75%的相对湿度下研究包合态丁香酚的释放。结果表明：丁香酚经过四周的释放,总体损失率没有超过10%,通过对Avrami方程的拟合,表明该包合物中丁香酚的释放属于扩散和一级反应共同控制的过程。利用热重分析仪,证明了β-环糊精对丁香酚的包合能提高了丁香酚热稳定性。采用牛津杯扩散法研究丁香酚/β-环糊精包合物的抑菌作用,得到丁香酚/β-环糊精包合物对大肠杆菌具有较为显著的抑制效果,而对乙型副伤寒菌、金黄色葡萄球菌的抑菌效果并不明显。同样采用冷冻干燥法,制得丁香酚搭载环糊精接枝微球功能材料。测定芳香功能组分丁香酚占微球的质量分数为2.6%,即该材料不但具有丁香酚香味,也能在抑菌领域具有潜在应用。6.采用原位还原技术将无机纳米态银粒子搭载在环糊精接枝纤维素微球载体材料之上,得到既具超分子包合能力又具强效杀菌性能的新型微球功能材料。采用扫描电子显微镜、X射线光电子能谱仪、电子背散射衍射仪等手段对新型微球功能材料进行表征,得到新微球材料表面银位点的粒径范围在500-800 nm之间,呈金属零价态形式分布,搭载纳米银后微球材料的表面形貌、粒径大小均没有明显变化。利用酚酞分子探针技术检测搭载纳米银前后微球材料表面活性环糊精含量,认为纳米银粒子的搭载不会影响微球表面环糊精的包合。通过原子吸收分光光度计,对搭载的纳米银粒子酸碱耐受性进行研究。结果表明：银粒子位点由于环糊精表面的配位作用而增加了其在酸溶液中的稳定性。采用试管二倍稀释法,得到新型微球功能材料对大肠杆菌和金黄色葡萄球菌最低抑菌用量分别为0.0125 g和0.025 g；最低杀菌用量分别为0.025 g和0.025 g。更多还原

【Abstract】 As the second generation supermolecular compound, cyclodextrin (CD) has a wide variety of guest molecules and shows a promising application in the fields of medical care, food, environment and molecule self-assemble. The combination of cyclodextrin and natural polymers for preparing cyclodextrin polymers, not only has the property of a cyclodextrin-specific, but also has the properties of easy modification, stability, environmental friendly and renewable which belongs to the natural polymers. Meanwhile, this investigation enlarges the application of cyclodextrin. Besides, as one of the most important forest biomass resources in the Northeast of China, cellulose is rich in storage but suffers from inadequate comprehensive utilization. Thereafter, the research, development and application of cellulose and its relevant areas have attracted great attention of many agricultural and forestry scientists and have become the hotspot and the emphasis of highly efficient utilization of biomass resources.In this paper, cellulose beads are prepared by our self-made circumrotation centrifugal machine. Host molecules of cyclodextrins are grafted onto the surface of the cellulose beads in the presence of polycarboxylic acids. Besides, nanoscale silver particles are also introduced onto the surface of the cellulose beads by the technique of in suit chemical reduction method. In the end, a multi-functional material of cellulose beads loading with inorganic nanoparticles is obtained. Meanwhile, the detection of cyclodextrin by phenolphthalein probe molecule, the preparation and characteristic of cellulose beads, the graft of cyclodextrin host molecule on cellulose beads surface, the encapsulation, release and application of iodine encapsulated byβ-cyclodextrin, the encapsultation, release and application of eugenol encapsulated byβ-cyclodextrin, the preparation, characteristic and application of cellulose beads loading with nanoscale silver particles are discussed in details. The contents and results of this article are included as follows:1. The binding constants (Ka) of phenolphthalein/β-cyclodextrin, phenolphthalein/(2-hydroxypropyl)-β-cyclodextrin, and phenolphthalein/(2,6-dimethyl)-β-cyclodextrin complexes were measured by ultraviolet-visible spectrophotometer. By regression of van’t Hoff plot, thermodynamic parameters (△H°and△S°) of these complexes’formation were obtained. Based on these parameters, steric hindrance influence, spontaneous, and enthalpically driven process for the interaction of phenolphthalein with cyclodextrins were further proved, and phenolphthalein, as a probe molecule, was used to determinate the cyclodextrins’ content due to less than 0.6% relative standard deviation and recoveries with the range of 90-103%.2. Cellulose beads were prepared by the natural cellulose fibers and controlled by three key steps during the preparation process, including the dissolving of the cellulose fiber, the preparation of the liquid cellulose beads and the solidification of the liquid cellulose beads. The viscosity of the xanthate solution was the main factor that influenced the preparation of the cellulose beads, for this reason, the influencing factors of the xanthate solution’s viscosity were also discussed in details. In the end, the results were demonstrated that the shape of products were kept in spherical, the packing density, tap density, true density, compression ratio and void ratio were 0.2780 g mL-1,0.2869 g mL-1,2.92%,0.4080 g mL-1,29.9%, respectively. The products of the cellulose beads showed a distinct physical property compared with the cellulose fiber and would have a potential investigation value on the application of the carrier materials.3. Functional host molecules ofβ-cyclodextrin were grafted onto the cellulose beads in presence of polycarboxylic acids, such as 1,2,3,4-Butanetetracarboxylic acid, citric acid, tartaric acid. The novelty of this study was the using of phenolphthalein probe molecule technique to determine the surface activity cyclodextrin contents. Based on the determination results of the method phenolphthalein molecule probe and weight gain, key factors of the grafting ofβ-cyclodextrin, including crosslinking agent, catalyst, curing temperature and cyclodextrin concentration in the impregnating bath, were investigated. Besides, the grafting of (2,6-dimethyl)-β-cyclodextrin and (2-hydroxypropyl)-β-cyclodextrin on the cellulose beads were also discussed. By discussing of the results of the phenolphthalein probe detection, a microscopic observation of the grafting process was given and a conception of surface activity cyclodextrin was put forward which describes the cyclodextrin’s ability of encapsulation on the modified cellulose beads.4. By regression of the Hildebrand-Benesi equation, the iodine/β-cyclodextrin (iodine/β-CD) binding constant of 1286 L mol-1 and the stoichiometric ratio of 1:1 (iodine:β-cyclodextrin) were obtained. Two major factors of encapsulation temperature and stirring time during the preparation process of the solid state iodine/β-CD inclusion complex were investigated. In order to determine the iodine content in the complex powder, a quantitative method by iodimetry was investigated, and its accuracy and expeditiousness were verified by high performance liquid chromatography (HPLC). Release behaviors of iodine/β-CD powder were investigated by iodimetry and thermo gravimetric (TG) analyzer respectively. The loss percentage of iodine was 5.8 wt.% for 7 days exposing under room temperature and a time versus release curve was established. The TG diagram not only proved the thermo stability of the iodine in iodine/β-CD complex, but also clarified the thermal decomposition behaviors of the iodine/β-CD. For verifying the germicidal activity of iodine encapsulated byβ-cyclodextrin, the aspergillus niger, which is a kind of common fungus in the food, was taken as evaluation media. By the method of disc diffusion, iodine/β-CD showed a bacteriostasis effect of aspergillus niger. In order to have functional properties, material ofβ-cyclodextrin grafting cellulose beads loaded with iodine guest molecule was prepared. The iodine content of this novel product was 3.1%, and the results demonstrated its application potential in bacteriostasis material.5. Solid state eugenol/β-cyclodextrin inclusion complex (EG/β-CD) was prepared by lyophilization method and characterized by Powder X-ray Diffraction (XRD) and Fourier Fransform Infrared Spectroscopy (FTIR). UV-vis spectrometer was used to determine the EG content encapsulated in the complex. In order to estimate the release characteristics of the EG/β-CD powder, Avrami’s equation and Thermogravimetric (TG) analyzer were respectively used. The loss percentage of EG was no more than 10 wt.% for 4 weeks when exposing at 25℃and 75% humidity, and the release of EG was controlled by a combination mechanism of diffusion and first-order mode. TG results not only proved the thermo stability of the EG in EG/β-CD complex, but also clarified the thermal decomposition behaviors of the EG/β-CD. The antibacterial activity of the EG/β-CD complex was investigated using agar cup-plate diffusion method and bacterial strains of Escherichia coli，Salmonella paratyphi B, and Staphyloccocus aureus were used. The results indicated that EG/β-CD had a selective antimicrobial active against Escherichia coli. Similarly, the material ofβ-cyclodextrin grafting cellulose beads loaded with eugenol guest molecule was also prepared by the lyophilization method, and the eugenol content was 2.6%. The results demonstrated that the novel material not only had the flavor of eugenol, but also had a potential application on bacteriostasis material field.6. In order to prepare a novel material with properties of encapsulation of functional guest moluecules and strong bacteriostasis effect, nano-sacle silver particles were deposited on the carrier material of cyclodextrin grafting cellulose beads. The surface of novel material was studied by Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS) and Electron Bachscattered Diffraction (EBSD). The results indicated that the size of nano-silver on the surface of the novel carrier material was in the range of 500-800 nm，and the valence state of the silver particles was kept at zero. The morphology and particle size of the novel materal were kept unchanged compared with the beads which were not deposited with nano-silver. Phenolphthalein probe molecule technique was used to detect the surface activity cyclodextrin content, and the results demonstrated that the deposition of nano-silver had no influence on the encapsulation ability of the cyclodextrins which were grafted on the surface of the cellulose beads. The acid and base resistance of the nano-silver on the bead materials was carried out by Atomic Absorption Spectrometer (AAS). The stability of the nano-silver was enhanced due to the coordination between surface cyclodextrin and nano-silver particles. Tube dilution method was used to study the bacteriostasis effect. The minimal inhibitory doses of the novel material against Escherichia coli and Staphyloccocus aureus were 0.0125 g and 0.025 g, respectively. The minimal bactericidal doses for the two bacteria were 0.025 g and 0.025 g, respectively.更多还原