【作者】 韩咚林；

【导师】 李疏芬； 闫立峰；

【作者基本信息】 中国科学技术大学 ， 物理化学， 2010， 博士

【摘要】 发展绿色环保新能源和新材料技术是当今化学研究的一大任务,而“绿色新能源、环保新材料”这类新兴产业也将成为我国下一轮经济发展的新引擎。铝/水（Al/H₂O）基燃料是一种采用金属铝作为燃烧剂,水作为氧化剂的新型高能燃料,具有可观的能量密度。另外,由于其燃烧产物污染非常小,它也是一种新概念的绿色环保型燃料。生物质作为可再生资源由于其生物降解性和具有在某些领域能够替代石油化学产品的特性而日益引人注目。纤维素和壳聚糖是生物质的主要组成部分,也是世界上储量最丰富的两类生物质高聚物原料,以纤维素和壳聚糖制备各类具有环境友好性和生物适应性的高强度的绿色材料已成为研究者关注的热点。本论文由两大部分组成。第一部分为新型浆态铝/水基燃料的主要组分对燃烧特性的影响,分析了粘合剂聚丙烯酰胺促进燃料燃烧的机理。考察了高能氧化剂六硝基六氮杂异戊兹烷（CL-20）和奥克托金（HMX）、纳米非晶态B-Co合金助燃剂、添加剂MMA等对铝/水燃料燃烧性能的影响。此外,对聚丙烯酰胺水溶液在300 oC、450 oC、600 oC时的闪速裂解机理也进行了详细探讨。第二部分是生物质类材料的制备及其功能性质的表征。本论文成功制备出纤维素/氧化石墨复合材料、壳聚糖/氧化石墨复合材料以及全纤维素薄膜材料,并对材料的结构进行了分析,对其特殊性能进行了测试。通过上述研究,本论文得到了如下的研究结果:（1）对铝/水基燃料和生物质材料的研究进展进行了综述——阐述了铝/水基燃料的基本性质、燃烧特性、提高燃料燃烧性能的方法以及生物质材料的结构性质和处理方法等。（2）研究了在氩气和空气环境中,铝/水基燃料的燃烧行为。实验结果表明,粘合剂聚丙烯酰胺和助燃剂纳米B-Co合金粉的加入,可以显著改善燃料燃烧性能;加入高能氧化剂HMX比加入CL-20更有利于燃料燃烧温度的提高。（3）对聚丙烯酰胺水溶液的闪速裂解生成物进行了离线GC/MS检测分析,提出了其裂解的机理,指出产物中的很多易燃物质是促进铝/水基燃料点火和持续燃烧的主要原因。（4）以碱性水溶液为溶剂,成功制备出纤维素/氧化石墨复合膜和丝质材料。该方法操作过程简单,用料低廉,可以说是一种制备纤维素/氧化石墨复合材料的绿色的方法。在氧化石墨含量低于7.5 wt%的复合物中,氧化石墨作为填充剂通过插层复合与纤维素基质均匀混合,界面间结合紧密,氧化石墨通过氢键作用与纤维素链联接起来,提高了复合材料的力学性能。此外,复合材料比纯纤维素材料在耐热性方面有很大的提高,在较高温度下复合材料仍然有良好的机械强度。（5）采用醋酸水溶液为溶剂,制备了壳聚糖/氧化石墨复合膜和水凝胶。研究发现无论是处于干态还是湿态的复合材料,其力学性能均有大幅度的提高,并复合材料具有良好的抗水溶胀性能。（6）以普通的滤纸为原料,采用新发现的绿色纤维素溶剂——PEG/NaOH为溶剂体系,通过对滤纸选择性溶解再填充压膜的处理方法制备出全纤维素薄膜。由于基质和填充材料均是滤纸纤维素,所制备的全纤维素具有很好的界面相容性,宏观上表现出很好的力学性能。全纤维素结构成型所需的浸泡处理时间为6个小时以上,通过自身纤维素的溶解和再生,纤维素的基质和填充材料有效地结合在一起。同时,发现全纤维素薄膜具有良好的透光性和防水性,有广阔的实际应用前景。此外,由于全纤维素材料完全由纤维素构成,所以材料具有环境友好性,是一种绿色的新材料。更多还原

【Abstract】 The new green material and new green energy become the propulsion of the economic development in China with global warming.Al/H₂O based fuel is one kind of new high-energy fuels, which adopts H₂O as the oxidant and Al as the fuel. The energy density of Al/H₂O based fuel is quite large. In addition, Al/H₂O based fuel is one kind of green fuels, whose combustion products have low pollution and are very friendly to the surroundings.As an alternative resource, biomass has been attracted a lot of attention recently for its potential application in both regenerated energy and substitutes for petroleum product. Cellulose and chitosan are the major component of the biomass and the most affluent biopolymer in the world, and they are also a potential feedstock for preparing different kinds of novel polymers and material which are environmentally friendly and biocompatible.The dissertation can be logically divided into two parts. Part I pays much attention to experimental investigations of Al/H₂O based fuel. The influences of some other addition agents, including nano amorphous state B-Co alloy, CL-20, HMX, MMA, etc., were studied, and some basic parameters were obtained. At 300 oC, 450 oC, 600 oC, the flash pyrolysis of the key addition agent polyacrylamide were carried out in argon, respectively. Moreover, the formation mechanism for liquid and gas products, as well as the effects on improving the characteristics of Al/H₂O propellant were discussed. Part II focuses on the preparation of cellulose/graphite oxide composites, chitosan/graphite oxide composites and all-cellulose composites. The morphology of the prepared composites were investigated, and the special properties of these composites were examed.The findings obtained from the above researches are summarized as following.（I） Research progresses on Al/H₂O based fuels and biomass, including some basic properties, the combustion behaviors, the improvement methods for fuels’characteristics, the structure and treatment for the biomass, and so forth, were reviewed.（II） A variety of experimental methods were employed to study Al/H₂O based fuels detailed. Nano amorphous state B-Co alloy was prepared. B-Co alloy was used as an addition agent for basic Al/H2O based propellant. The addition of PAM evidently improved the energy release and burning rate of propellants, as well as decreased the pressure exponent. Besides, HMX addition not only had better effect in increasing the temperature of burning surface but also made Al powders burn much thoroughly, compared with CL-20 addition.（III） At 300 oC, 450 oC and 600 oC, the flash pyrolysis investigation of polyacrylamide （PAM） solution was carried out in an off-line furnace-type pyrolyzer with Ar as the carrier gas. There were a few flammable small molecules, which were believed to favor the combustion of the propellants and improved the energy release. （IV） Regenerated cellulose （RC）/graphite oxide （GO） blend films and fibers were prepared in 6wt%NaOH/4wt%urea aqueous solution via a simple and low cost pathway. The results revealed a certain miscibility, good thermostability and mechanical properties of the regenerated-cellulose composites blending with less than 7.5 wt% of GO. All the results demonstrated that GO was well-dispersed in the cellulose matrix, and there were strong H-bonding between hydroxy groups of the cellulose and hydroxy groups of the GO. The obtained composites own higher mechanical strength than the pure regenerated cellulose film, especially at high temperature.（V） Chitosan/graphite oxide composite films and Hydrogel have been prepared in which graphite oxide （GO） is used as filler and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and GO, respectively. The results revealed that chitosan and graphite oxide mixed with each other homogeneously and the mechanical properties were improved significantly compared with the pure chitosan. Interestingly, with an increase ratio of chitosan to GO from 1.5/0.1 （wt/wt） to 1.5/0.3 （wt/wt）, the tensile strength of the films at dry and wet states increased from 80.3 to 137.5MPa and 14.6 to 43.9 MPa, respectively. All the results demonstrated that GO was crosslinker in the composites, and there were strong H-bonding between hydroxy groups of the chitosan and hydroxy groups of the GO. The obtained composited films owned higher mechanical strength than the pure chitosan film, especially at wet state.（VI） PEG/NaOH aqueous solution, a recently reported solvent system for cellulose was utilized to prepare an all-cellulose composite. The composite was produced from commercial filter paper by converting a selective dissolved fiber surface into a matrix. When the filter paper was immersed in the pre-cooling solution more than six hours, the all-cellulose composites are molding. Such composite has possessed a nice interface between the remaining fibers and the surrounding matrix from the selectively dissolved and re-solidified fiber surface, which results in an excellent bonding, a high mechanical performance and an optical transparency. In addition, the all-cellulose composite is totally composed of sustainable cellulosic resources, so it is biodegradable after service.更多还原