微波辐射法合成葡萄糖苯酚树脂胶黏剂

以葡萄糖代替甲醛合成一种新的环保型酚醛树脂胶黏剂。在碱性条件下以微波加热法合成葡萄糖苯酚树脂胶黏剂、通过正交实验获得最佳反应条件,同时以此方法对树脂的固化条件进行了研究。微波加热条件下合成葡萄糖苯酚树脂胶黏剂的最佳条件是：葡萄糖：苯酚=7：1;pH：12;催化剂用量：1．4％;反应时间：6min。实验证明,微波辐射波法可以成功合成葡萄糖苯酚树脂胶黏剂,且该胶黏剂是一种环保型胶黏剂。     

高吸水性树脂超声波法制备研究进展及趋势

综述了超声波法制备高吸水树脂研究进展,包括超声波法制备合成聚合物系列高吸水树脂、超声波法制备天然多糖交联型高吸水树脂、超声波法制备接枝天然多糖型高吸水树脂等。最后指出了超声波法制备高吸水树脂研究需要加强的几个方向:即加强超声波法制备各种类型高吸水树脂的实验研究;加强超声辐射产生设备的革新研究;降低成本,扩大应用领域。     

微波法接枝改性天然胶乳的制备与表征

采用微波辐射的方法对天然浓缩胶乳进行接枝改性,单体选用甲基丙烯酸甲酯,考察了微波温度、时间、引发剂和单体用量对接枝率、接枝效率的影响,用傅里叶变换红外光谱仪、核磁共振波谱仪来表征接枝产物。结果表明,微波法接枝改性天然胶乳的方法是可行的;适宜的反应条件为:采用过硫酸钾和亚硫酸钠作为引发剂,其用量为0.4%(占橡胶质量的百分数),微波温度为80℃,反应时间为1～2h,单体与胶乳质量比为1∶1。     

高吸水性树脂的辐射合成

综述了高吸水性树脂合成的一种新的工艺方法———辐射合成,对天然高分子的接枝和合成树脂的共聚,以及悬浮工艺及其影响因素进行了讨论。     

离子交换晶胶层析分离甘草多糖的研究

甘草多糖是甘草提取物中的重要活性组分,具有免疫调节和抗氧化等多种药理作用,对其进行分离纯化的研究具有重要意义。研究探索了一种利用晶胶介质分离甘草多糖的新途径。以预处理和水提甘草根粉末得到的粗多糖为原料,用甲基丙烯酸二甲氨乙酯接枝聚丙烯酰胺晶胶基质制备得到的阴离子交换晶胶介质,对甘草多糖进行了快速层析分离,得到了精制的甘草多糖,确定了适宜的工艺条件。结果表明,阴离子晶胶介质可以吸附甘草多糖,其层析分离迅速;以去离子水为床柱平衡、冲洗及洗脱液配置的基础液,在流速1 cm·min-1条件下,晶胶介质对甘草多糖的吸附容量达670μg·m L-1晶胶,说明晶胶层析可作为天然药用多糖快速分离的一种新方法。     

微波辐射在高分子材料降解中的应用

综述了微波在天然高分子材料和合成高分子材料降解反应中的应用研究情况,分析了微波辐射对高分子材料降解反应特点,并指出了微波在高分子降解的实际应用中所面临的问题.     

淀粉接枝共聚改性研究进展

接枝共聚淀粉是一种新型功能性材料。介绍了接枝共聚改性淀粉的应用,从微波辐射技术、微波聚合技术紫外光技术的应用和复合引发剂的应用、新的乳液聚合方法应用等方面详细综述了淀粉接枝共聚改性研究的进展。指出了未来接枝改性淀粉的研究重点。     

微波辐射法制备聚吡咯纳米材料及性能研究

通过正交实验确定了微波辐射法合成聚吡咯的最佳条件。结果表明,微波辐射条件下,以吡咯(Py)为单体,当微波功率为10 W,十二烷基苯磺酸钠(SDBS)的质量浓度为0.02 g/mL,温度为0℃,反应30 min时,所得聚吡咯各项性能最好,其电导率可达67.32 S/cm,所得聚吡咯颗粒粒径在20~80 nm之间。通过FTIR、SEM等方法对所得材料的结构、形貌进行了表征,利用四探针技术测试了材料的电导率,利用热失重(TG)法对所得产物的热稳定性进行研究。通过微波辐射法成功合成了聚吡咯纳米材料,实验结果表明微波辐射在一定程度上改善了聚吡咯的形貌、结构与性能。此外,与一般化学氧化方法相比,微波辐射法显著缩短了反应时间,且未使用氧化剂,节约了生产成本。通过对微波辐射法制备聚吡咯的研究,期望能为将来大规模生产性能优异的聚吡咯提供一种新的可行工艺方案。     

硒多糖的提取和制备研究进展

硒多糖是一种新型的有机硒化合物,兼具硒和多糖的功能,具有提高免疫力、降血糖、抗氧化、抗肿瘤等多种功能,天然硒多糖种类少、含量低、结构复杂.硒多糖的合成方法主要包括微生物转化法、植物转化法、人工合成法等.硒多糖提取一般采用热水浸提法、碱提法、微波法、超声法和酶解法等.本文对硒多糖的来源、提取和制备等研究进行综述,期望为研究硒多糖提供理论依据.     

微波在合成天然有机高分子改性絮凝剂中的应用进展

微波辐射技术具有能耗低、反应速率快且有助于改善产品品质的特点,为合成天然有机高分子改性絮凝剂提供了新的思路。简述了微波合成的发展和机理,介绍了近年来微波辐射技术在合成天然有机高分子改性絮凝剂中的应用,展望了微波促进天然有机高分子改性的发展方向。     

Use of microwave irradiation in the grafting modification of the polysaccharides - A review

Polysaccharides are a natural and renewable feed stock for synthesizing high performance macromolecular materials. A popular, versatile and convenient route to develop polysaccharide based materials is the grafting of synthetic polymers onto natural polysaccharides. In spite of the attractive chemical and physical properties of polysaccharide based copolymeric materials, undesired homopolymer formation in the concurrent competing reaction lowers the copolymer yield, posing problems in the commercialization of the grafting procedures. Moreover, the requirement for an inert atmosphere is an added disadvantage for many conventional grafting procedures. The use of microwave irradiation has been exploited in the past two decades to alleviate these limitations in the synthesis of a range of graft modified polysaccharide materials. Indeed, increasing interest in clean and green environment friendly chemistry has motivated the use of microwaves in the polysaccharide grafting modification for various applications. Microwave irradiation significantly reduces the use of toxic solvents, as well as the reaction time for almost all the grafting reactions of interest here, ensuring high yields, product selectivity and clean product formations. Moreover, in many instances, microwave synthesized polysaccharide copolymers exhibit better properties for commercial exploitation than their conventionally synthesized counterparts. This review highlights recent applications of microwave heating in the grafting modifications of polysaccharides and discusses the underlying mechanisms and issues.     

Microwave promoted grafting of acrylonitrile onto Cassia siamea seed gum

Cassia siamea seed polysaccharide was grafted with acrylonitrile under microwave (MW) irradiation without adding any radical initiator or catalyst. Free radicals are generated here due to the dielectric heating caused by the localized rotation of the hydroxyl groups at the polysaccharide backbone and initiate grafting. To obtain the optimal conditions for the microwave promoted grafting, effect of reaction variables such as monomer/seed gum concentration; MW power and exposure time on the graft copolymerization was studied and the maximum %grafting (%G) and %efficiency (%E) observed were 150% and 43.54%, respectively. The representative graft copolymer was characterized by Fourier transform‐infrared, Thermogravimetric analysis and X‐ray diffraction measurement, taking C. siamea gum as reference. At the same monomer concentration, K₂S₂O₈/ascorbic acid initiated grafting onto the seed gum could result into 80% grafting with 23.22% efficiency. Various properties of the MW synthesized grafted gum like water/saline retention, water retention after saponification and viscosity of the gum solutions were studied. The results have been compared with the conventionally synthesized grafted gum and the parent gum. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2384–2390, 2006     

Recent Progress on the Design and Applications of Polysaccharide‐Based Graft Copolymer Hydrogels as Adsorbents for Wastewater Purification

Gum polysaccharides are one of the most abundant bio‐based polymers. They are generally derived from plants as exudates or from microorganisms and have diverse applications in many industries, especially in the food industries where they are used as emulsifiers and thickeners. In their natural form, gum polysaccharides have poor mechanical and physical properties; therefore, they are frequently modified with various synthetic monomers such as acrylamide and acrylic acid using graft copolymerization. Graft copolymerization is one of the most trusted and widely used synthetic methods for the modification of gum polysaccharides. Gum polysaccharides modified in this way have improved mechanical and physicochemical properties. Furthermore, gum polysaccharides contain a variety of functional groups, for example, carboxylic acid and hydroxyl groups; therefore, they have been used extensively as adsorbents for the removal of different impurities from wastewater such as toxic heavy metal cations and synthetic dyes. Here, the chemical and physical properties of gum polysaccharides, different methods of graft copolymerization, and the use of graft copolymer gum‐polysaccharide‐based hydrogels are reviewed in detail for the removal of toxic heavy metal cations and synthetic dyes from aqueous solutions.

     

Tamarind Seed Polysaccharide-g-Poly(N-Vinyl-2-Pyrrolidone): Microwave-Assisted Synthesis,Characterization, and Evaluation as Mucoadhesive Polymer

Graft copolymer of N-vinyl-2-pyrrolidone and tamarind seed polysaccharide was prepared using microwave assisted graft copolymerization and evaluated for mucoadhesive applications. Graft copolymerization was optimized using response surface methodology employing microwave power and exposure time as the independent variables, and grafting efficiency as the response variable. The buccal patches of metronidazole formulated using the graft copolymer showed ex vivo bioadhesion time of 9.3 h with >80% of the drug getting released while the buccal patches formulated using tamarind seed polysaccharide showed ex vivo bioadhesion time of 5 h releasing only 50% of the drug.     

黄原胶与丙烯酸接枝共聚反应的研究

以过硫酸钾为引发剂,在氮气保护下,研究了黄原胶（XG）与丙烯酸（AA）的接枝共聚反应。考察了单体浓度、引发剂浓度、反应温度和反应时间等因素对接枝率及接枝效率的影响,探讨了过硫酸钾引发黄原胶接枝丙烯酸共聚反应的基本规律。采用红外光谱（FT—IR）对接枝共聚物的结构进行研究,并初步探讨了接枝机理。     

黄原胶与丙烯酰胺接枝共聚反应的研究

以过硫酸铵为引发剂,在氮气保护下,研究了黄原胶与丙烯酰胺的接枝共聚反应。考察了单体浓度、引发剂浓度、反应温度和反应时间等因素对接枝率及接枝效率的影响,探讨了过硫酸铵引发黄原胶接枝丙烯酰胺共聚反应的基本规律。采用红外光谱、X射线粉末衍射对接枝共聚物的结构进行研究,用热重分析法表征了产物的热性能,并初步探讨了接枝机理。结果表明,过硫酸铵能有效地引发黄原胶与丙烯酰胺的接枝共聚反应,并且接枝率和接枝效率随单体浓度、引发剂浓度、反应温度的变化出现极大值,随反应时间的延长不断上升,直至基本不变。     

Effect of chemical modification of a natural polysaccharide on its inhibitory action on mild steel in 15% HCl solution

Many of the synthetic corrosion inhibitors being used currently, are toxic and therefore research for developing environmentally benign corrosion inhibitors is of great importance. Inhibitors such as natural polysaccharides of plant origin are popular due to its non-toxic nature. Here, the toxicity of a natural polysaccharide, guar gum, and its modified form, cationic guar gum was studied and their inhibitory effects were investigated by gravimetric, electrochemical and surface morphology studies. Both the inhibitors are found to be effective and their adsorption on metal is in accordance with the Langmuir adsorption isotherm. Experimental results are in consonance with the results of quantum chemical calculations by density functional theory.     

罗望子胶的生产工艺研究

罗望子胶是一种多糖类天然食品增稠剂、稳定剂和胶凝剂。本文研究了从豆科罗望子属植物罗望子种子中提取罗望子胶的生产工艺,并就罗望子胶生产工艺中原料的处理,不同有机酸对罗望子种仁粉的水解,蛋白质沉降,胶的色泽和收率进行了比较试验,提出了简便、易于生产和提高罗望子胶纯度的方法     

Synthesis of a well‐defined chitosan graft poly(methoxy polyethyleneglycol methacrylate) by atom transfer radical polymerization

Graft copolymerization of vinyl monomers onto chitosan and other natural polymers using atom transfer radical polymerization has only recently attracted interest. This technique could potentially provide new ways to utilize this abundant natural polymer. It would enable a wide variety of molecular designs to afford novel types of tailored hybrid materials composed of natural polysaccharides and synthetic polymers. In this work, a chitosan macroinitiator was prepared by the reaction of chitosan with 2‐bromo‐isobutyryl bromide, after the chitosan amino group had been protected as the imine. The aqueous grafting of methoxy capped (PEG 350) methacrylate onto chitosan is described. The kinetic study revealed a first order polymerization reaction. Polydispersities of about 1.25 were obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 901–912, 2003