4种N-对位取代苯基马来酰亚胺单体的光引发聚合初探

探讨用偶氮二异丁腈(AIBN)作光敏剂对4种N-对位取代苯基马来酰亚胺单体光引发均聚的可能性,然后用AIBN、氯化苄、二乙基二硫代氨基甲酸烯丙酯(BDC)作光敏剂,研究了4种N-对位取代苯基马来酰亚胺和苯乙烯的光聚合,得到相对分子质量可控、产品纯度高、粉末细腻的光聚合产物,可用作高档精细高分子产品。     

N—（α—甲基—戊酯基—）马来酰亚胺树脂的合成与表征

以马来酸酐（MA）、D,L－氨基丙酸（Aln）、正戊醇为原料经三步二釜法合成既含不对称碳原子又含官能团（酯基）的新型马来酰亚胺单体N－（α-甲基－戊酯基－）马来酰亚胺（PAM）,并以AIBN为引发剂,用溶液聚合法合成了聚N－（α-甲基－戊酯基－）马来酰亚胺,并用IR、TG、DSC对聚合物进行了表征。     

N-烷基马来酰亚胺的合成及在光固化中的应用

合成了6种N 取代马来酰亚胺(MI),以MI为光引发剂分别引发了丙烯酸化的脂肪族聚氨酯EB230预聚物、1,6 己二醇二丙烯酸酯(HDDA)和二缩三丙二醇二丙烯酸酯(TPGDA)的光固化,研究了MI的浓度和结构、单官能稀释剂及双官能稀释剂对光固化的影响。结果表明:MI的浓度和结构对光固化有一定影响;醋酸乙烯酯(VAc)降低了光固化速度,苯乙烯(St)则阻止了光固化的发生;双丙烯酸酯的结构对光固化也有影响。     

双酰亚胺类蛋白质荧光探针的合成

以6种N 取代 4 氨基 邻苯二甲酰亚胺及马来酸酐为起始原料合成了相应的6种N (N 取代 邻苯二甲酰亚胺 4 基) 马来酰亚胺(Ⅱ)。丙酮为溶剂,氮气保护,室温下N 取代 4 氨基 邻苯二甲酰亚胺及马来酸酐反应2 5h得到N (N 取代 邻苯二甲酰亚胺 4 基) 氨基马来酰酸(Ⅰ),收率均>90%。Ⅰ在三乙胺与乙酐作用下,脱水环合生成N (N 取代 邻苯二甲酰亚胺 4 基) 马来酰亚胺(Ⅱ),反应收率达69%～85%。各步产物经1HNMR、IR确定结构。在研究脱水环合反应的过程中,分离得到其中一种产物的反应中间体:N (N 丁基 邻苯二甲酰亚胺 4 基) 氨基马来酰酸乙酸酐(Ⅲ),由此推测该反应为五元环过渡态的SN2亲核取代机理。     

N—苯基马来酰亚胺合成方法的改进

以苯胺和顺酐为主要原料合成耐热改性剂N－苯基马来酰亚胺过程中，采用有机碱三乙胺作催化剂，同时加入金属铜盐阻聚剂，使N－苯基马来酰亚胺的产率比文献报道用乙酸钠作催化剂时明显提高，达到85％。加入四聚剂后，N－苯基马来酰亚胺的纯度提高到99％以上。     

苯乙烯与N－苯基马来酰亚胺本体共聚合动力学

研究了Ｎ－苯基马来酰亚胺在苯乙烯中的溶解度和络合性能，以及聚合温度、Ｎ－苯基马来酰亚胺浓度、引发剂种类及浓度、加料方式等因素对共聚合速率的影响，进一步分析和计算该体系的动力学和热力学参数。     

苯乙烯与N—苯基马来酰亚胺本体共聚合动力学

研究了Ｎ－苯基马来酰亚胺在苯乙烯中的溶解度和络合性能，以及聚合温度、Ｎ－苯基马来酰亚胺浓度、引发剂种类及浓度、加料方式等因素对共聚合速率的影响，进一步分析和计算该体系的动力学和热力学参数。     

几种N-取代苯基马来酰亚胺单体的合成与表征

以马来酸酐、苯胺及其衍生物为主要原料合成了N-对甲苯基马来酰亚胺(NM PM I)、N-对氯苯基马来酰亚胺(NCLPM I)、N-对甲氧苯基马来酰亚胺(NM OPM I),产率可达85%以上。采用1H-NM R,13C-NM R和FT-IR等仪器对产物及中间产物马来酰胺酸的结构进行详细的表征。研究发现马来酰胺酸和马来酰亚胺苯环上不同的取代基,在1H-NM R谱图中,对HC=CH上质子峰的影响不大,而对苯环上质子峰却有影响,吸(供)电子基使苯环质子的化学位移向低(高)场移动;在13C-NM R谱图中,含强电负性(O、N、C l)的取代基使苯环上δc1低场移动,邻对位δc略向高场移动,取代基的电负性越大,位移也越大。     

N-苯基马来酰亚胺的应用与合成

叙述了N -苯基马来酰亚胺的用途及合成方法。通过分析ABS及PVC的市场前景 ,提出了在国内开发N -苯基马来酰亚胺的必要性和紧迫性。     

N-对甲苯基马来酰亚胺(NMPMI)/甲基丙烯酸甲酯(MMA)共聚合研究

根据自由基共聚合和交联改性有机高分子材料的原理,以偶氮二异丁腈(AIBN)为引发剂,甲苯为溶剂,N-对甲苯基马来酰亚胺(NMPMI)和甲基丙烯酸甲酯(MMA)为原料,采用溶液聚合法合成了N-对甲苯基马来酰亚胺/甲基丙烯酸甲酯共聚物,并研究了原料配比、引发剂用量、反应时间、温度等工艺条件对产品收率的影响,确定了共聚合反应...     

民用工业中复合材料桁架的应用和发展

本文叙述了复合材料桁架的构造、分类和计算方法,突出了复合材料桁架的优越性能和在民用工业中的应用前景;在分析大量文献资料的基础上阐述复合材料桁架杆件的多种加工工艺,并比较不同截面形式对杆件性能的影响;探讨复合材料杆件的破坏机理和分析方法,介绍节点的类型和各自的特点,提出节点及连接部位存在的关键问题;根据国内外复合材料桁架的研究和应用现状,阐述了复合材料桁架的性能和不同的设计方法,总结归纳影响复合材料桁架性能的关键因素和设计中存在的一些问题,并提出改进杆件设计、节点设计和优化复合材料桁架的建议。     

生物质热解制生物油及其提质研究现状

生物质能源作为可再生能源的重要组成部分,其综合高效利用在能源替代与补充、保护生态环境等方面具有重要的战略意义。生物油是生物质通过热裂解技术获得的液体产物,具有能量密度较高、环境友好、可再生及可直接输送等优点,可替代传统化石燃料推广使用,解决日益严重的能源紧缺与环境污染等问题。生物质热解制油技术的开发与利用,已成为新世纪可持续能源研究领域的重要课题之一。总结了近年来生物质热解制油技术的主要研究进展,重点关注热解反应器、催化热解技术与生物油的提质利用方面的研究,介绍了碱金属、氧化物和分子筛3种生物质热解催化剂,以及乳化、催化加氢、催化裂解、催化酯化和重整制氢5种生物质提质方法,最后对生物质热解技术的现状及发展趋势进行了总结和概括。     

Environment and colour: The technological interface

Technology and colour are viewed as interfaces between the environment, humans and human activity. Examples are provided of ways of facilitating and improving access to and use of colours by commercial users of colour coatings through improvements in the accuracy of measuring and displaying colour. By analogy, the task of providing effective interfaces within the coatings industry, between the coatings industry and the environment and between the coatings industry and the public and political domain are discussed. Examples of information shortfalls are cited to illustrate how distortions arise. Examples of more effective, integrated technological, organisational and political interfacing are culled from the author's experiences.     

Mechanical Means of Enhancing Drying Rates: Effect on Drying Kinetics and Quality

The effect of various pretreatments on drying kinetics as well as quality parameters of selected vegetables and fruits was studied experimentally in a convective dryer. The pretreatments tested include application of pinholes and drilled holes of different diameters and densities, blanching and freezing. Potato, cassava, dragon fruit and red chilli were used as the sample drying materials. As expected, increase of the diameter and density of the holes under fixed drying conditions increased the drying rate. Samples with drilled holes showed better drying performance than those with pinholes. The improvement of the drying rate was found to be dependent on the physical properties and the initial moisture content of the material. Results show that the drying performance of the products that possess a skin of low moisture diffusivity, such as chilli, can be improved significantly by blanching and making perforations in the skin. Overall changes of color and volume shrinkage during drying of the samples with and without holes were similar. The effect of different modes of heat input, such as convection, conduction and radiation, on the drying performance of the treated samples was also experimentally investigated. On-off type controllers were used to regulate the power of the heaters and maintain the product temperature within a range of pre-set values. Convection combined with radiation displayed the highest drying rate.     

颗粒介质用机械密封热力耦合变形及摩擦磨损研究

在含有颗粒介质的工作环境中下,硬质材料配对机械密封环的热力耦合变形和摩擦磨损对机械密封的泄漏和使用寿命起着至关重要的作用。考虑动静环和颗粒介质的摩擦,试验测定了摩擦系数,建立了动静环热力耦合的有限元计算模型,研究了WC-Co硬质合金和无压烧结碳化硅（SSiC）陶瓷两种硬质材料密封的温度场和端面变形规律,分析了不同工况下的密封间隙变化规律。试验测试分析了密封环温度、磨损前后的泄漏及表面粗糙度,讨论了端面的磨损机理,验证了计算模型的准确性。结果表明：考虑动环磨粒摩擦热的有限元模型能准确地预测密封的温度和端面变形;耦合作用下动静环端面呈现外径脱离、内径贴合的变形,且变形差异程度随压差和转速的增大而加剧;变形导致端面磨痕分布不均匀,内径磨痕较严重。WC-Co硬质合金配对密封环的端面变形小、泄漏量小,高硬度WC颗粒对Co基体能产生很好的“阴影效应”,具有良好的耐磨粒磨损性能。SSiC陶瓷材料韧性差,易产生片状磨屑,形成过渡型磨粒磨损,材料耐磨性较差,泄漏量增加明显。在磨粒工况下,WC-Co硬质合金机械密封具有泄漏小、耐磨性强的特点。研究结果为颗粒介质中机械密封的材料应用及设计优化提供了参考。     

Solubility of light alkanes and alkenes in ionic liquids

The solubility of light hydrocarbons in a variety of ionic liquids was studied, and it was found that ionic liquids containing Cu(Ⅰ) had higher solubility for hydrocarbons and alkene/alkane solubility selectivity, and Et₃NHCl-2.1CuCl ionic liquid was preferred. The effects of temperature and pressure on the solubility of light hydrocarbons were investigated for the selected ionic liquid. It was found that low temperature and high pressure were favorable for the dissolution of light hydrocarbons, and the alkene/alkane solubility selectivity decreased with the increase of temperature and pressure. The alkene/alkane solubility selectivity was above 8.3 at the temperature of 30℃ and the pressure of 0.2 MPa. The initial dissolution rate of hydrocarbons in ionic liquid was large, but it decreased rapidly with prolonging time, and the dissolution rate of alkenes was higher than that of alkanes at the same conditions. The alkene/alkane separation selectivity increased with decreasing content of alkenes in the mixture of alkenes and alkanes. Light hydrocarbons dissolved in ionic liquids could be desorbed by means of increasing temperature, restoring the dissolution capability of ionic liquids to hydrocarbons. Alkanes were easier to be desorbed than alkenes, and small-molecule hydrocarbons were easier to be desorbed than large-molecule hydrocarbons. The desorption percentage exceeded 92% under optimal conditions. Ionic liquid had a good reusable performance in the absorption and separation of light alkanes and alkenes. The solubility only decreased by less than 5% when it was reused five times, and the alkane/alkane solubility selectivity was basically not affected by reusing times. Software Gaussian 09 was used to study the interaction between anions of ionic liquids and light alkanes and alkanes, and the solubility difference of light alkenes and alkanes in different ionic liquids was well explained.     

木质纤维生物质半纤维素分子模拟应用研究进展

木质纤维生物质资源是重要的可再生生物质资源,主要包含纤维素、半纤维素和木质素。半纤维素含量仅次于纤维素,是一种丰富、可再生的植物资源,其可水解制备重要化学品以及改性制备多功能材料。本文综述了生物质半纤维素分子模拟应用研究进展,从半纤维素大分子形态及其与纤维素结合方式的分子模拟研究和半纤维素制备化学品及材料的分子模拟研究2个方面进行阐述,从模拟结果可以看出半纤维素在细胞壁中与纤维素和木质素的相互作用及其本身的大分子形态对木质纤维生物质三大素的提取利用具有显著影响。分子模拟有利于理解过程机理,对反应效率的提高具有重要理论指导意义。最后对分子模拟在半纤维素研究的发展应用进行了展望,指出目前半纤维素分子模拟的空白领域,主要包括半纤维素液化生产生物油、木糖异构化生产木酮糖、半纤维素与木质素之间的结合方式以及其他的半纤维素基材料等,这些有待进一步的探索与研究。     

Micromechanics of machining and wear in hard and brittle materials

Hard and brittle solids with covalent/ionic bonding are used in a wide range of modern-day manufacturing technologies. Optimization of a shaping process can shorten manufacturing time and cost of component production, and at the same time extend component longevity. The same process can contribute to wear and fatigue degradation in service. Educated development of advanced finishing protocols for this class of solids requires a comprehensive understanding of damage mechanisms at small-scale contacts from a materials perspective. The basic science of attendant deformation and removal modes in contact events is here analyzed and discussed in the context of brittle and ductile machining and severe and mild wear. Essentials of brittle–ductile transitions in micro- and nano-indentation fields are outlined, with distinctions between blunt and sharp contacts and axial and sliding loading. The central role of microstructure in material removal modes is highlighted. Pathways to future research—experimental, analytical, and computational—are indicated.     

硅酸锌加压硫酸浸出的热力学分析与实验研究

计算绘制了Zn-Si-H2O系ET-pH图,分析了硅酸锌硫酸浸出和原硅酸高温脱硅的热力学可行性. 通过人工合成硅酸锌的加压酸浸实验,考察了始酸浓度、终点pH值、铁含量、硫酸铝添加量、浸出温度对硅酸锌酸浸和硅酸凝聚的影响. 结果表明,升高浸出温度能有效降低硅溶胶的稳定性且有利于原硅酸的高温脱硅过程,进而改善矿浆的过滤性能;硫酸铝能促使硅溶胶凝结析出,可降低硅酸浓度;控制恰当的矿浆终点pH值和Si/Fe及Si/Al质量比均有助于硅析出. 在浸出温度120℃、浸出时间0.5 h、液固比8 mL/g及H2SO4浓度120 g/L的优化条件下,锌、硅浸出率分别约为98%和1%.     

聚苯胺及其衍生物在杀菌防污领域的应用进展

抗菌剂在涂料、膜、生物智能材料等材料表面的防污领域有着极其重要的应用价值。随着环保意识的增强，长效、环境友好型的抗菌剂成为当前研究的主流。其中，聚苯胺由于其良好的生物相容性和物理化学性能，是一种极具潜力的抗菌剂。聚苯胺的抗菌机理可由自身的氧化还原活性、阳离子吸附效应及电化学活性3方面分析。概括了聚苯胺及其衍生物的结构及制备方法；进一步从杀菌防污机理出发，综述了聚苯胺及其衍生复合材料在不同防污材料中应用的研究进展，包括在接触杀菌型表面、释放杀菌型表面、抗黏附型表面3种类型的材料中的应用。此外，提出了聚苯胺在防污应用中需进一步解决的问题及发展方向。