PVC阻燃材料在建筑中的应用

主要介绍了无机阻燃剂、有机阻燃剂和复合型阻燃剂改性的聚氯乙烯(PVC),以及这些阻燃剂对PVC阻燃性能的影响。其中无机阻燃剂的阻燃效果最为明显,不过消烟效果较差;有机阻燃剂消烟效果较为明显,但阻燃能力不如无机阻燃剂;复合型阻燃剂兼具有机/无机阻燃剂的优点,或具有多种无机阻燃剂的优点,一般既具有较强的阻燃能力,又具有较为显著的消烟效果,是未来PVC用阻燃剂的发展方向。     

硅系阻燃剂在聚烯烃中的应用

硅系阻燃剂具有一系列优异的性能,拥有巨大的开发和应用前景。介绍了有机硅阻燃剂的阻燃机理,综述了无机硅系阻燃剂、有机硅树脂阻燃剂、有机硅改性阻燃剂等在聚烯烃中的应用。     

聚丙烯阻燃剂的应用

叙述了磷氮系阻燃剂、硅系阻燃剂、水合金属化合物阻燃剂、膨胀型阻燃剂等非卤系阻燃剂和含卤阻燃剂在聚丙烯阻燃性研究中的应用情况,分析了不同阻燃剂对聚丙烯阻燃性能和力学性能的影响。认为卤系阻燃剂会放出有毒的烟和气体,故应向无卤阻燃剂方向发展;磷氮系阻燃剂具有协同阻燃效果,并对环境友好,同时还有隔热、抑烟等作用;硅系阻燃剂能改善基材的机械性能和耐热性能;水合金属化合物阻燃剂具有无毒、无腐蚀性、耐高温的特点的优点,但加入的量较大,会对聚丙烯的性能产生较大的影响。膨胀型阻燃剂是一种环保的绿色阻燃剂,在燃烧时产生的烟雾少、毒性低,会在表面生产炭质泡沫层,起到隔热、隔氧、抑烟等功效,符合未来阻燃剂研究开发的方向。     

有机磷阻燃剂的研究进展

由于有机磷阻燃剂具有高效、低毒、无污染及无烟等特点,该领域的研究在国内外得到极大的关注。综述了磷酸酯类阻燃剂、膦酸酯类阻燃剂和磷杂环类阻燃剂的研究进展,并提出了有机磷阻燃剂今后的发展方向。     

有机磷阻燃剂的研究进展

由于有机磷阻燃剂具有高效、低毒、无污染及无烟等特点,该领域的研究在国内外得到极大的关注。综述了磷酸酯类阻燃剂、膦酸酯类阻燃剂和磷杂环类阻燃剂的研究进展,并提出了有机磷阻燃剂今后的发展方向。     

含磷阻燃剂在天然纤维织物阻燃中的应用

含磷阻燃剂具有高效、低毒等特点,广泛应用于阻燃织物中。文章对含磷阻燃剂的阻燃机理,各种含磷阻燃剂在天然纤维阻燃织物中的应用和研究现状以及含磷阻燃剂中磷元素和其他元素间的协同阻燃效应进行了简单介绍,并列出了一些含磷阻燃剂的主要优缺点。     

高效膨胀无卤阻燃剂性价比优

无卤阻燃剂主要包括膨胀型阻燃剂和无机阻燃剂等,膨胀型阻燃剂是以磷、氮为阻燃元素的阻燃剂,含有这类阻燃剂的高分子材料受热分解或燃烧时,表面能生成一层均匀的多孔炭质泡沫层。该泡沫层具有隔热、隔氧功能,还有抑烟和防止熔滴的作用。膨胀型阻燃剂符合当代对材料抑烟、低毒的要求。东北林业大学研发的高效膨胀无卤阻燃剂已在黑龙江沃尔德电缆有限公司成功实现产业化,     

溴系阻燃剂的应用研究及发展趋势

经过对溴系阻燃剂的市场消费量的分析,表明溴系阻燃剂是一时难以被替代且具有良好发展前景的阻燃剂。阐述了溴系阻燃剂的特点和阻燃机理,重点介绍了阻燃体系中溴系阻燃剂产品及阻燃技术的开发与应用。并针对溴系阻燃剂在使用中存在的二英和毒气等问题,提出了新的研究方向,预测了溴系阻燃剂今后的发展趋势。     

我国水环境中主要阻燃剂及其处理

综述了我国阻燃剂生产使用的现状,概述了阻燃剂大致可分为有机阻燃剂、无机阻燃剂和金属阻燃剂,介绍了阻燃剂对人体以及自然的危害,概括阻燃剂在实际中的应用以及阻燃剂带来的环境污染问题。通过联系大气环境、土壤环境以及实际情况,介绍阻燃剂在自然环境中的迁移,着重分析阻燃剂进入水环境以及阻燃剂在水环境中的转化途径,综述电子、纺织等工业生产、使用阻燃剂是阻燃剂进入水环境的重要途径;降雨使得空气中的阻燃剂溶于雨水,流入市政管网,最终排放河流进入水环境中。由于阻燃剂污染的严重危害,分析阻燃剂废水具有高总磷及高COD等特点,是一种较难处理的废水。根据现在阻燃剂废水处理的实践和研究情况,汇总一些阻燃剂废水处理方法、工艺,主要介绍吸附、萃取工艺、电解法和高级氧化工艺以及化学沉淀等废水处理工艺流程,研究各个工艺的实际处理效果。此外还将各个工艺处理效果进行对比,结合技术经济和运行的实际情况推选出较优工艺为电解、高级氧化结合化学沉淀工艺。最后对我国阻燃剂处理及其污染的控制提出了建议与展望。     

聚丙烯膨胀型阻燃剂研究进展

膨胀型阻燃剂是一类环保型阻燃剂,目前用于聚丙烯的膨胀型阻燃剂在国内外己开展了大量的研究工作。综述了近年来国内外聚丙烯的膨胀型阻燃剂的研究进展以及相关的硅烷协效剂、金属协效剂和其它一些协效剂在阻燃体系中的应用,并对研发具有优良阻燃性能和力学性能的聚丙烯膨胀型阻燃剂的一些研究思路进行了归纳和介绍。     

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。     

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。     

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.     

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。     

可生物降解分离膜材料及其应用研究进展

在绿色化学理念的引导下,可生物降解膜材料受到了广泛的关注,有望成为传统分离膜材料的补充和替代品。本文首先分析了传统的不可降解分离膜材料的现状及问题,然后综述了当前较为热门的几种可生物降解膜材料,讨论了它们的发展状况,详细介绍了它们在膜相关领域中的应用,并针对它们的局限性做出了说明并提出了一些解决方案。随后,分析了可生物降解膜材料的生物降解机理,从分子结构角度对膜材料的可生物降解性进行了说明,这将有利于剖析膜材料生物降解的本质,进而平衡膜材料在使用中的稳定性和生物降解性。最后,文章对可生物降解膜材料在发展中遇到的问题进行了展望,并指出随着研究的不断深入,可生物降解膜材料具有广阔的前景和深远的现实意义。     

Lipid distribution on textiles in relation to washing with lipases

Effectiveness of lipase in detergency was studied using three test soils (lard, artificial sebum, and olive oil) on a woven cotton fabric. Distribution of oily soil on fabrics was determined for three different treatments (unwashed, washed with detergent without lipase, and washed with detergent plus lipase). Osmium tetroxide was used to label lipid soil for analysis in the scanning electron microscope. Both longitudinal and cross-sectional backscattered electron images for unwashed samples showed that soil was present on surfaces of the cotton fibers and in interfiber spaces of the yarn bundle. Lard soiled samples had large deposits on the fabric surfaces, while artificial sebum and olive oil appeared more uniformly distributed throughout the textile. Oil was deposited in the interfiber capillaries of the yarn bundle and in the crenulation, secondary walls, and lumen of the fibers. Energy dispersive X-ray microanalysis was used to determine relative concentrations of oil at selected morphological locations within the fiber structure and at the fiber surface. Soil distributions within the fibrous structures differed with type of soil and laundry treatment. Backscattered electron images dramatically demonstrated the effect of lipase on cleaning. After washing with detergent plus lipase, yarn surfaces had much less residual soil; residual soil that remained was in the irregularities of the cotton fiber surfaces. Concentrations of oil in the secondary walls, crenulations, lumen, and the fiber surfaces were lower after lipase treatment for all three soils. While washing with detergent removed soil from the yarn and fiber surfaces and the crenulation of the cotton fiber, only the samples washed with detergent plus lipase had lower concentrations of soils within the secondary wall and lumen of the cotton fibers. Fabrics soiled with olive oil and washed with detergent plus lipase had the lowest concentrations of residual soil across the textile structure; the residual soil observed was mainly in the irregularities on the fiber surfaces.     

COMBINED INNOVATIVE HEAT PUMP DRYING TECHNOLOGIES AND NEW COLD EXTRUSION TECHNIQUES FOR PRODUCTION OF INSTANT FOODS

There is an increased demand for convenient foods including ready-to-eat and instant products. These products are desired with minimum concentration of synthetic chemicals. This creates challenges for the food industry and dryers manufactures to develop new technologies to process difficult-sensitive materials and to supply final products with high quality and improved properties. Fruits and vegetables are mainly composed of water, carbohydrates, proteins and lipids. Due to modification of chemical and physical bonds the compounds the material becomes viscous and sticky during processing. Conventional dryers have limitations in handling such sensitive materials. Heat pump dryers have been applied in the production of a diversity of ready-to-eat foods and dried instant products for the last five years at SINTEF-NTNU. Besides being energetically efficient and environmentally friendly, the heat pump drying technology provides a wide range of drying conditions as required to produce powders with improved characteristics. This work describes the new technologies and processing line for the production of instant foods as well as the measurements on the properties and quality attributes for raw, intermediate and final instant products.     

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.     

基于甘草配伍黄芩同时泡沫分离甘草酸和黄芩苷

为了同时分离甘草中有表面活性的甘草酸和黄芩中无表面活性的黄芩苷,开发了甘草配伍黄芩泡沫分离工艺。通过荧光光谱、紫外吸收光谱和红外吸收光谱分析表明,甘草酸与黄芩苷存在相互作用,并且甘草黄芩配伍强化了甘草酸和黄芩苷的提取。以甘草酸和黄芩苷的富集比和回收率为评价指标,当温度为40℃、气体体积流量为100 ml·min^-1、甘草酸初始浓度为0.2 g·L^-1、甘草黄芩质量比为3：1时,获得甘草酸的富集比和回收率分别为11.0和73.5%,黄芩苷的富集比和回收率分别为5.8和38.5%。通过甘草与黄芩配伍,利用泡沫分离获得黄芩中的黄芩苷。同时,与单独泡沫分离甘草中甘草酸相比,甘草酸的富集比提高了194.9%,回收率提高了23.3%。因此,甘草配伍黄芩能有效泡沫分离甘草酸和黄芩苷。     

The Influence of Temperature and Pressure During the Curing of Prepreg Carbon Fiber Epoxy Resin

The physical and hence mechanical properties of carbon fiber reinforced epoxy resin are affected by the curing conditions used in their manufacture. The relationship between the cure temperature and pressure and the density, fiber volume fraction, and the void content of cured laminates, was investigated. For the unidirectional 914C prepreg material used, an optimum cure temperature was found which gave maximum fiber volume fraction and composite density, and minimum void content. This behavior is related in the paper to resin flow and cure characteristics. A linear relationship between cure pressure and fiber volume fraction is reported and explained by reference to the void content of the laminates. It is concluded that in-house trials are required to determine the optimum size of the processing window for specific systems and components.