【作者】 何英姿；

【导师】 魏远安；

【作者基本信息】 广西大学 ， 化学工艺， 2005， 博士

【摘要】 本文研究并开发了一种新的方法合成蔗糖基聚合物。由于蔗糖基聚合物具有富于吸引力的独特性能,如亲水性、生物活性、生物降解性等,从20世纪90年代开始,国际上研究以蔗糖为原料制备这类聚合物的兴趣不断增长。蔗糖基聚合物可以由传统的化学法和酶法合成。本文采用一种新的合成途径——预辐射聚合法制备蔗糖基聚合物,已申请国家发明专利,是一种清洁、可控、可靠的合成途径。蔗糖在有空气的条件下进行⁶⁰Co的γ射线辐照,辐照后使蔗糖有了引发活性,活化蔗糖和另一种单体（如丙烯酸）发生聚合反应,从而生成蔗糖基聚合物。反应条件温和、清洁,室温下反应在水溶液中进行,无需添加任何引发剂或其它化学试剂。 本文研究了蔗糖预辐射剂量、温度、反应物料配比对蔗糖基聚合物的粘均相对分子质量和产率的影响。要获得适合于农业生产应用的蔗糖基聚合物,其相对分子量为6万左右,蔗糖和丙烯酸的最优聚合反应条件为:预辐射剂量1kGy、反应温度为常温20℃;反应时间15h;水、蔗糖与丙烯酸配比为5:5:1（v/w/v）。对其反应机理也做了初步探索,初步确定为自由基引发聚合。在有空气的情况下经⁶⁰Co的γ射线预辐照,蔗糖产生的自由基和氧结合生成了稳定的过氧化物,使蔗糖晶体拥有了引发活性（以活化蔗糖的形式）,在辐射场外,采用均相体系溶液聚合,丙烯酸单体以水为溶剂,预辐照的活化蔗糖既是引发剂又是单体,在溶液内由自由基引发蔗糖与丙烯酸的聚合反应,反应15小时,生成蔗糖基聚合物。产物进行分离纯化,并用核磁共振、红外光谱、紫外光谱和扫描电境对其进行了结构表征,该聚合物与已报道的蔗糖基聚合物不同,扫描更多还原

【Abstract】 A New method to synthesize sucrose-based polymer (SBP) was developed and investigated. The use of sucrose in the production of polymers is of growing interest from 1990’s, since such polymers demonstrated some attractive and unique properties such as hydrophilicity, biological activity, biodegradability, etc. Conventionally, Sucrose-based polymers were prepared by chemical techniques and enzymatic methods. The new approach, designated as pre-irradiation method and was patented, was found to be a clean, controllable and reliable synthesizing pathway to prepare SBP. Sucrose crystal was pre-irradiated by γ -ray of 60Co and turned into an activated form, then the activated sucrose was polymerizes directly with another monomer (e.g. acrylic acid) to yield SBP, the reaction occurred mildly and cleanly, just in aqueous and room temperature, without any addition of other initiator or chemical.The effects of pre-irradiation dose, reaction temperature, monomer concentration ratio to the relative molecular weight and yield of the polymers were studied. To gain the sucrose-based polymer with 60,000 relative molecular weight which is suitable for agricultural use, the optimal co-polymerization reaction conditions of sucrose with acrylic acid wereestablished as the following: pre-irradiation dose for sucrose, 1kGy; reaction temperature, 20 ℃; reaction time, 15h; monomer concentration ratio, 5:5:1 (water: sucrose: acrylic acid). The preliminary study on reaction mechanism shown the reaction is a radical polymerization. When the samples of sucrose was irradiated with 60Co-gamma radiation under the atmosphere with oxygen, free radicals are generated as stable peroxide that may make the sucrose crystal possessed the activity of initiation (in an activated form). Moved the sucrose away from the radiation field, and simply following regular solution polymerization method in a homogeneous phase system, that is, acrylic acid and the activated sucrose (acted as both the monomer and the initiator) were dissolved in water and reacted for 15 hours, the sucrose-based polymer was obtained. The resulting SBP was separated and further purified, and characterized by 1H NMR, 13C NMR, UV, IR spectra and SEM. The data suggested that it might be a sort of polymer that is different from the previously reported polymers. From the observation by scanning electron microscope, it was found that these polymers consisted of a porous structure. So the SBP is easy to dissolve in water and the thin membrane formed by its solution is proved to possess good ventilative property.More interestingly, the resulting SBP from the pre-irradiation method was found not only the good biodegradable materials, but a novel plant growth regulator (or stimulator) as well.The research of the application of SBP was carried out in several aspects. First, SBP can be used as preservative agent for fruit. Mango, one type of subtropical fruit, was dipped into the solution of SBP and a thin film coated on the surface of Mango. The result showed that the SBP coating film could reduce the respiration intensity of mango and could prevent partially the fruit from microorganism eroding, avoid water evaporating quickly, therefore,prolong the storage life of mango and preserve the original flavor and taste of mango. At normal temperature, the processed mango can be stored 19 days with 80% percentage of good fruits. Secondly, applying SBP as plant growth regulators to the crops, the yields of Pleurotus Ostreatus and maize was increased 20 %, in comparison with the yields of the control. Moreover, SBP was found to be able to raise the soluble solids content and total sugar content, reduce the titratable acidity in the fruits of longan, mango, lanii and malon, and have the function of sweetness enhancement.The investigation in the plant interior responding mechanism to SBP application was also turned out some very interesting results. The experiments data indicated that SBP can increase the chlorophyll content and the rate of photo synthesis of the leaf of the plant, and at the same time decre更多还原