高性能水泥基材料的复合原理——特高强无机有机复合水泥互穿网络结构的形成条件及机理

详细论述了MDF水泥材料国内外研究现状及发展趋势,高强机理及长期稳定性,材料的组成、结构与性能的关系。同时,也提出了一些具体研究内容和技术方案,以及预期达到的各项指标。     

MDF水泥材料的纤维增强研究

研究了玻璃纤维和碳纤维的长径比、体积掺量对MDF水泥诸多性能的影响.结果表明,碳纤维和玻璃纤维作为MDF水泥的增强材料均能够显著提高MDF水泥的力学性能和耐水性,玻璃纤维的效果优于碳纤维.     

掺粉煤灰的MDF水泥材料结构与性能研究

研究了用粉煤灰部分替代水泥而制备的HAC/PVA基MDF材料的强度、水敏性与结构,试验结果表明,粉煤灰细粉的掺入虽然改善了MDF水泥材料的孔结构和水敏性,但却明显降低其力学性能,用硅烷偶联剂对粉煤灰和水泥进行表面改性,则能显著提高粉煤灰MDF水泥材料的抗折强度,进一步改善其水敏性。     

高强水泥材料暨抗静电活动地板

湖南省建材研究设计院研制成高强水泥材料暨抗静电活动地板。这种产品已申请了中国专利。高强水泥材料暨抗静电活动地板是在 MDF 水泥基础上开发的新型实用性产品,在 MDF 水泥材料实际应用开发方面,处于国际领先水平。它可广泛应用在计算机机房、电     

无宏观缺陷水泥复合材料研究进展

无宏观缺陷(MDF)水泥复合材料作为一种新型的材料,是高强水泥发展的一个重要分支.对MDF水泥复合材料的特性、加工工艺及湿敏性产生的原因进行全面的介绍,论述了近些年国内外克服MDF水泥湿敏性的措施.对MDF水泥发展前景进行展望,并指出了目前存在的问题.     

MDF水泥材料的研究和应用

本文阐述了无宏观缺陷水泥材料(MDF cement)的制备方法、性能、微观结构以及聚合物与水泥的相互作用,探讨了该材料的增强机理、介绍了在一些特殊领域中的应用前景。     

PRAC高性能水泥基复合材料

一．前言为了克服水泥制品抗拉强度和抗折强度低的缺点,英国Birchall等人研究开发了MDF（macro－defect-free）聚合物—水泥复合材料。他们采取的技术途径是降低灰水比、加人聚乙烯醇（PVA）以提高搅拌时的流动度、降低硬化体中的孔隙率和减小孔隙的尺寸,他们用高铝水泥—PVA制备的MDF的抗折强度达到200MPa。但是,由于MDF采用水溶性的聚合物,存在耐水性和耐热性差的缺点。为了解决MDF的耐水性、耐热性,使之成为21世纪的新材料,用于汽车、航空、航天和电子等领域,以美国伊利诺伊斯大学J．F.Young等人为代表的许多水泥基材料…     

超高强水泥材料的研制

一、前言超高强水泥材料也称无宏观缺陷水泥材料(MDF)。1979年英国化学工业公司和牛津大学就着手对超高强水泥材料进行研究,之后,瑞典、丹麦、日本和美国等也相继研制这种材料,并报道了他们的成果。现在,已研制出来的超高强水泥材料,其抗压强度可高达200～300MPa,抗折强度高达150～200MPa。同时,这种材料的抗拉、抗冲击、抗渗、耐磨等性能与传统水泥材料相比,都有了明显的改善,这为扩大水泥材料     

改善MDF水泥的新方法

MDF 水泥(Macro Defect-free Cement),因其制品内部大孔隙含量很少,或者为零,故称为无宏观缺陷水泥。这种水泥材料的抗压、抗拉、抗折、抗冲击强度和耐磨、抗渗等性能大大     

MDF水泥材料的后期强度

本文介绍了在MDF水泥材料中添加改性剂后,使其产生新的水化产物,并促使常规水化矿物发生变异,从而达到防止材料后期强度下降的目的.     

MDF水泥耐水性研究

采用憎水性酚醛树脂代替亲水性聚合物,从根本上解决了无宏观缺陷（MDF）水泥的耐水性问题．结果表明,高铝水泥／酚醛树脂MDF水泥具有优良的耐水性．     

Recent developments in macro-defect-free (MDF) cements

During the early 1980s macro-defect-free (MDF) cements were developed which had properties complimentary to those of conventional ceramics, plastics and metals. The research completed on MDF cements, and particularly the polyvinyl-alcohol/calcium aluminate cement (PVA/CAC) system has been reviewed and the advantages, limitations and potential applications of MDF cements are outlined. The microstructural features of the PVA–CAC MDF systems and the influence this has on physical properties such as flexural strength and moisture resistance are discussed. Possible solutions to the poor moisture resistance of MDF cements are examined critically and alternatives to PVA–CAC described. The recent development of calcium aluminate phenol resin (CAPR) MDF cements that have particularly promising properties is presented. MDF cement technology has the potential to produce more sustainable materials that can compete with ceramics, plastics and metals in a range of applications and key research issues that need to be addressed if MDF cements are to become commercially viable are highlighted.     

纤维网对MDF水泥基层压复合材料抗折性能影响的研究

用玻璃纤维网，铜纤维网和尼龙纤维制备了多种纤维网ＭＤＦ水在层压复合材料，由Ｉｎｓｔｒｏｎ８５０１万能材料试验机测试了这些层压复合材料的三点弯曲全荷载－挠度曲线，研究了不同纤维网对ＭＤＦ水泥基层压复合材料抗折性能的影响。     

Influence of organic coatings on the stability of macrodefect-free cements exposed to water

It is known that macrodefect-free (MDF) cements show instability in water, with swelling and reduction in strength. The weight and dimensional changes of three MDF cements, formulated from different aluminous cements, during immersion in quiescent tap water, were evaluated. The results show that the cement with the highest Al₂O₃ percentage had the lowest degradation after prolonged immersion. Hence, this material was selected for further analysis. As the time taken for water to diffuse into the body of MDF composites is considered a key factor in the collapse of their mechanical properties, the effect of organic coatings with different barrier properties on the composite behaviour, when exposed to water, was studied. The water permeability of seven surface coatings was evaluated by electrochemical impedance spectroscopy (EIS). Three of them were chosen for application to the selected MDF cement. The data presented show that the application of organic coatings, not necessarily characterised by extremely low water permeabilities, improves the stability of the composite when subjected to different conditions of exposure to water.     

Comparison of formaldehyde emission from building finishing materials at various temperatures in under heating system; ONDOL

The objective of this research was to investigate the effect of various temperatures, room, 37 and 50 degrees C, on formaldehyde emission from floor materials, such as laminate and plywood floorings, and furniture materials, such as MDF and particleboard veneered with decorative paper foil, by desiccator's method. The temperature conditions were set up by, measuring the temperature in a Korean under heating system. To maintain an indoor air temperature of 20 degrees C, the temperature of the flooring surface was about 37 degrees C and the temperature of the cement mortar was 50 degrees C. The initial formaldehyde emission of the laminate flooring and plywood flooring was 1.44 and 0.63 mg/l, and for MDF and particleboard it was 4.73 and 4.95 mg/l, respectively. Floor materials were under E1 grade while furniture materials were under E2 grade in terms of formaldehyde emission. Because of the under heating system, the flooring materials were exposed to 37 and 50 degrees C, while the furniture materials mostly existed at room temperature. At 37 and 50 degrees C, the formaldehyde emission level of the flooring materials was already under 0.3 ppm (F level by JIS A 1460, application possibility without area limit) after 10 days and the emission had decreased further (0.03-0.10 mg/l) after 28 days. These levels are not injurious to the human body and will not cause sick house syndrome (SHS). The problem, however, is the furniture materials such as MDF and particleboard. As these materials are not exposed to high temperature (50 degrees C in this experiment) in living condition, it was still E2 grade of formaldehyde emission level at room temperature remained even after 28 days. Although there will be variations with the volume of furniture materials and the indoor conditions, furniture materials are the principal cause of indoor air quality pollution in Korean with the under heating system. PRACTICAL IMPLICATIONS: Koreans spend most of their time sitting on ONDOL (heated) floors, with their buttocks always in contact with the floor surface. The flooring materials are exposed to high temperatures (37-50 degrees C) why the effect of bake-out is rapid. The emission of formaldehyde from furniture materials are more important for the IAQ because usually MDF and particleboard of E2 grade are being used as furniture materials in Korea.     

尼龙纤维网增韧MDF水泥材料抗折性能的研究

通过Ｉｎｓｔｒｏｎ８５０１万能试验机测试了多层尼龙纤维网增韧ＭＤＦ水泥材料的三点弯曲全荷载挠度曲线，研究了不同纤维直径和不同层数的纤维网对ＭＤＦ水泥材料抗折性能的影响     

夹点技术原理及在建材行业的应用和研究

我国的建材行业是国民经济发展的一个重要的基础材料产业,随着近几年我国的城镇化发展,建材行业也随着迅速发展,但由于同时它又是一个高能耗的产业,所以如何对建材行业进行节能降耗的改造也是如何保障建材行业可持续发展的一项非常重要且迫切的工作。本文介绍了如何应用夹点技术对企业的工业系统和换热网络进行分析和改造,从而达到节能降耗的目的．     

木质类建材的自身吸声特性及影响因素

采用驻波管法测定分析了实木、中密度纤维板、胶合板、刨花板等常见木质建筑材料的吸声特性,并分析了影响因素.实验结果显示:实木吸声性能较差,在各频率下的吸声率均小于20%;中密度纤维板、胶合板和刨花板的吸声性能略优于实木.降噪能力排序为:中密度纤维板>胶合板>刨花板>实体木材.在吸声频谱特性方面,实木、纤维板、胶合板和刨花板的吸收峰中心频率位于1000 Hz附近.在吸声影响因素方面,板厚度、密度和涂饰与否是影响木质材料吸声性能的重要因素,板厚度的增大、面密度的减小都有助于木质材料中低频吸声率的提高,但涂饰会使其吸声率有所降低,木质人造板涂饰后吸声性能的降幅要超过实木.