聚氯乙烯/粉煤灰复合材料的制备与性能研究

制备了聚氯乙烯/粉煤灰复合材料,研究了粉煤灰的不同表面处理方式对共混物的力学性能和耐温性能的影响。结果表明:湿法处理粉煤灰的效果最好,不做处理的效果最差;粉煤灰会降低PVC材料的缺口冲击强度;添加5份处理过的粉煤灰可以提高PVC材料的拉伸强度;添加粉煤灰可以提高PVC材料的弯曲强度和弯曲模量,同时,耐温性也有一定的提高。     

Evaluation of Coupling Agents in Poly(propylene)/Fly Ash Composites: Effect on Processing and Mechanical Properties

Composites containing 50 wt.‐% fly ash in a PP homopolymer were prepared via batch mixing and compression moulding. The following coupling agents were evaluated: Lubrizol Solplus C800, N,N′‐(1,3‐phenylene)dimaleimide, γ‐methacryloxypropyltrimethoxysilane and maleic‐anhydride‐grafted PP. At the filler level investigated, C800 gave the best balance of composite strength and toughness. In the latter case filler‐matrix adhesion appeared weaker relative to γ‐MPS, BMI and m‐PP, all of which gave excessively strong filler‐matrix adhesion leading to a reduction in composite toughness. The unexpected weakness of the C800/fly ash interaction may be related to removal of surface calcium ions from the fly ash via reaction of a single calcium ion with two C800 molecules.

     

高掺量粉煤灰PVA-ECC的力学性能研究及粉煤灰作用机理分析

主要研究了高掺量粉煤灰对PVA-ECC力学性能的影响,对粉煤灰掺量分别为40%、50%、60%情况下PVA-ECC的抗压强度、薄板四点弯曲性能等进行试验研究,并分析了粉煤灰在ECC中的作用机理.结果表明:随着粉煤灰掺量的增加,ECC的抗压强度呈降低趋势,四点弯曲试验中ECC试件的初裂荷载和峰值荷载降低,跨中挠度增加,且裂缝宽度减小;高掺量粉煤灰下,纤维长度对ECC抗压强度和延性有较大的影响,掺12 mm纤维的PVA-ECC在保证强度的同时,可获得较高的延性和韧性.     

粉煤灰细化与表面改性及其填充改性聚丙烯性能的研究

用燃煤电厂产生的废弃物粉煤灰作为填料,将粉煤灰进行物理球磨细化改性,再用硅烷偶联剂活化改性,然后与聚丙烯（PP）通过熔融共混制备成复合材料。结果表明,球磨后的粉煤灰制成的复合材料相比于纯PP弯曲强度提高了11.5 %,而且这种复合材料的拉伸强度和冲击强度相比于填充未球磨粉煤灰的材料分别提高了10.7 %和34.1 %,并且其熔体流动速率和热稳定性都有较大提升;经过硅烷偶联剂活化后的粉煤灰制成的复合材料,其力学性能,热稳定性也都得到改善;实验证明粉煤灰的填充对PP有很好的增强增韧效果,并且当改性之后的粉煤灰填充量为20 %（质量分数,下同）时,综合性能最佳。     

机械活化粉煤灰性能的研究

研究了机械活化时间对粉煤灰的视密度、比表面积、粒度分布及活性的影响。将不同时间机械活化的粉煤灰按 3 0 %比例掺入硅酸盐水泥中 ,测定其净浆强度。结果表明 ,球磨时间以 2 0min～ 3 0min为宜     

粉煤灰加气混凝土砌体力学性能与节能效应分析

利用室内试验方法制备了粉煤灰加气混凝土砌块和砌体,分别测试了混凝土砌块的抗拉抗压强度和砌体的抗拉和抗剪强度,分析了砌体抗压和抗剪强度随砂浆厚度的变化规律。在此基础上,建立了粉煤灰加气混凝土砌体节能效应的FLAC 3D数值计算模型。研究表明:(1)粉煤灰加气混凝土砌块的抗拉压强度平均值分别为4.53 MPa和0.75MPa;(2)粉煤灰加气混凝土砌体的整体抗压和抗剪强度随砂浆厚度的增大而分别减小和增大;(3)粉煤灰加气混凝土砌体的平均传热系数小于普通灰砂砖砌体,且随砂浆厚度的增大而减小。     

HDPE‐Fly Ash/Nano Fly Ash Composites

Fly ash (FA) based polymer composites are assuming increasing importance because of its potentiality, fine particle size and plenty availability of FA. FA is mainly a mixture of inorganic metal oxides such as SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, Na₂O, TiO₂, and so forth. This article highlights the results of the various modifications onto the HDPE‐FA/nano structured FA (NFA) composites. When FA and NFA are melt blended with HDPE it gives rise to improved flexural properties only. Further modifications, that is, Maleic anhydride (MA) grafting of the matrix, electron beam irradiation of the composite and irradiation of the FA/NFA studied separately to find their impact on the detail properties of the composite. Of the three modifications implemented the electron beam irradiation of HDPE‐FA/NFA composite yielded excellent physico‐mechanical, thermal and dynamic mechanical properties. Fracture surface analysis of the HDPE, unmodified and modified FA/NFA composites studied employing SEM correlated well with the physico‐mechanical properties. The results prove that FA is valuable reinforcing filler for HDPE and its size reduction to nano level is a more effective criterion for its future use. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4558–4567, 2013     

粉煤灰喷射混凝土力学性能及其在露天煤矿边坡中的应用

本研究制备粉煤灰喷射混凝土试件,测试了粉煤灰喷射混凝土的基本力学特性,得到了喷射混凝土的最佳粉煤灰掺量;提出了露天煤矿边坡的"挂网+粉煤灰喷射混凝土"加固处理方法;模拟分析了暴雨条件下粉煤灰喷射混凝土加固前后边坡稳定性。研究结果表明:粉煤灰喷射混凝土的最佳粉煤灰掺量为20%;采用"挂网+粉煤灰喷射混凝土"对露天煤矿边坡进行加固后,其在暴雨条件下的整体稳定系数由0.98增大至1.48,满足安全开采要求。     

喷射粉煤灰混凝土微观结构和力学性能试验研究

为研究喷射粉煤灰混凝土在养护过程中微观结构和力学性能的变化,采用X-射线衍射法、热重-差示热法、扫描电镜法对喷射粉煤灰混凝土微观结构进行分析,并对其1d、3d、7d、28 d、60 d、90 d和180 d的抗压强度、劈裂抗拉强度进行研究.结果表明:养护龄期对喷射粉煤灰混凝土微观结构和力学性能影响大,且微观结构与力学性能之间存在密切联系.龄期为1d时,由于速凝剂的作用,喷射粉煤灰混凝土强度较高.龄期低于28 d时,粉煤灰等量替代水泥,控制水泥水化速度的有效水灰比相对增大,喷射粉煤灰混凝土抗压强度和劈裂抗拉强度随粉煤灰掺量增加下降;龄期高于28 d时,粉煤灰活性被激发,喷射粉煤灰混凝土微观结构变得密实,喷射粉煤灰混凝土抗压强度随粉煤灰掺量增加先上升后下降,劈裂抗拉强度随之上升.     

UV固化水性聚氨酯/粉煤灰复合材料的制备及其涂膜性能的研究

将微米级的粉煤灰(FA)用于可紫外光固化水性聚氨酯的改性,以改善水性聚氨酯的耐水性能。首先用KH-550对粉煤灰进行表面改性,再通过偶联剂中—NH2基团与异佛尔酮二异氰酸酯(IPDI)的反应制得表面带有—NCO基团的改性粉煤灰。原位反应制备可紫外光固化的WPU/FA复合材料,复合体系中粉煤灰的掺杂量达到5%。利用扫描电子显微镜(SEM)观察了粉煤灰颗粒及复合物薄膜的表面形态,测试结果证明这种回收利用的无机粒子能够改善水性聚氨酯材料的耐水性能和机械性能,其耐热性能也有明显的提升。     

Fire Retardancy Characteristics and Mechanical Properties of High-Density Polyethylene/Ultrafine Fly Ash/MWCNT Nanocomposites

Nanocomposites of high-density polyethylene along with ultrafine fly ash and acid-functionalized multiwalled carbon nanotubes have been developed. To enhance the interfacial adhesion, an epoxy-functionalized high-density polyethylene has been added, while the ultrafine fly ash has been surface modified using aminosilane-coupling agent. Improvement in mechanical properties using both ultrafine fly ash/multiwalled carbon nanotubes was seen and was further analyzed using micromechanical models. The addition of ultrafine fly ash and multiwalled carbon nanotubes together exhibited synergism leading to lowering of peak heat release rate. The nanocomposites showed enhanced thermal stability and lowered crystallinity percentage values of the high-density polyethylene phase due to improved interfacial interactions.     

芳纶纤维、粉煤灰对混凝土性能的影响

研究了掺加芳纶纤维、粉煤灰对混凝土的力学、抗渗性能的影响。结果表明,芳纶纤维、粉煤灰对混凝土的抗压强度影响不明显,抗折强度、抗渗性能得到明显提高。掺加0．6％的芳纶纤维和10％的粉煤灰时,试样的力学性能和抗渗性能最优,抗折强度提高了30．77％,抗压强度提高了5．69％,抗渗性能提高了24．6％。     

煤矸石对粉煤灰陶粒滤料性能的影响

以粉煤灰、黏土为主料,添加不同比例的造孔剂煤矸石制备粉煤灰陶粒滤料,研究了煤矸石用量对粉煤灰陶粒滤料性能的影响,结果表明,随着煤矸石比例的提高,粉煤灰陶粒滤料的烧失量、吸水率及比表面积逐渐增大,而堆积密度、强度和耐酸碱性逐渐减小。     

石门沟贮灰场粉煤灰动静力性质试验研究

本文结合微水电厂石门沟贮灰场的工程性质对粉煤灰进行了比较系统的试验研究。研究表明,单用粉煤灰填筑子坝技术上完全可行,在遇７度地震时稳定性也是有保证的     

季冻区粉煤灰加固路基土力学性能试验研究

为探究冻融循环作用对粉煤灰加固路基土力学性能影响,对冻融循环次数、含水率、粉煤灰掺量不同的盐渍土开展无侧限抗压试验和三轴剪切试验,研究冻融循环后土体的应力-应变曲线、无侧限抗压强度、黏聚力和内摩擦角的变化情况。使用Design-Expert 8.0软件,研究冻融循环次数、粉煤灰掺量、含水率及各因素交互作用对盐渍土力学性质影响的显著性程度。结果表明:多次冻融循环后,盐渍土无侧限抗压强度、黏聚力和内摩擦角均有下降,经历1~7次冻融循环时,土体各力学参数下降速率较快;随着粉煤灰掺量的增加,盐渍土的内摩擦角、黏聚力、无侧限抗压强度和抗剪强度呈现出先升高后下降的变化趋势。基于显著性分析理论,冻融循环次数与含水率的交互作用对盐渍土无侧限抗压强度和黏聚力的影响较为显著,粉煤灰掺量与冻融循环次数的交互作用仅对无侧限抗压强度影响较为显著。为提高路基土强度及抗冻融的能力,加快粉煤灰综合利用进度,根据软件和公式模拟结果,推荐在路基土中依据质量比掺加15%粉煤灰,并将经历7次冻融循环后压实盐渍土的力学指标作为工程设计参考值。     

粉煤灰与减水剂双掺混凝土力学性能研究

从双掺混凝土力学性能出发,分析了粉煤灰的掺入量对混凝土力学性能的影响,得出了粉谋灰的最大掺入量.     

粉煤灰填充双组分聚氨酯防水涂料的制备

研究了粉煤灰填充双组分聚氨酯防水涂料的效果。粉煤灰的细度对防水涂料的固化速度和涂膜性能都有影响。当粉煤灰的细度为300目时能得到性能优良的双组分聚氨酯防水涂料。     

粉煤灰地聚合物力学性能影响因素研究综述

粉煤灰地聚合物是以粉煤灰为硅铝质原料制备的,具有强度高、耐高温、耐腐蚀、有效固封金属离子等优点.但它固有的脆性以及需高温养护才能快速获得高强度的特点限制了其运用范围,而以纤维作为增强材料不仅可以提高粉煤灰地聚合物的强度,还可以改善其延性和韧性.本文主要从粉煤灰原料特性、碱激发剂、养护制度和增强材料四方面入手,重点阐述了...     

界面强度对玻璃纤维增强不饱和聚酯复合材料静态和动态力学性能影响

采用3种高强高模玻璃纤维与不饱和树脂,分别制备了3种单向板复合材料和3种织物复合材料,通过纤维束拔出法和韦布分析法表征了3种玻璃纤维与不饱和树脂间的界面结合强度,并研究了界面强度与复合材料静态和动态力学性能。结果表明:3种纤维的本征界面强度分别为27.12,34.91,35.60MPa;界面强度对复合材料静态力学与疲劳性能有着重要的影响,但对模量的影响较小。随着界面强度的增加,90°方向的拉伸强度逐渐增加,但是0°方向上的拉伸强度反而下降。当疲劳应变较低时,界面强度的增加有助于疲劳性能的提高;但当疲劳应变提高时,界面强度对疲劳性能的影响降低,与材料初始强度反而有着明显的相关性。     

Comparison of Water Absorption and Mechanical Behaviors of Polypropene Composites Filled with Rice Husks Ash

Composite materials were obtained by filling polypropene with raw and thermally treated rice husks at filler contents from 1 to 20%. The physicochemical properties were determined. A slight increase was observed in the tensile strength of the composites based on white rice husk ash (WRHA) and aerosil (AR) at degree of filling up to 3%. Young's modulus increased and the elongation at break and energy to break point showed a tendency to decrease for all the composites studied. The thermodynamics and kinetics of water absorption at immersion were studied in the temperature interval 25–90°C. The values of the changes in standard free energy, ΔG°, enthalpy, ΔH°, and entropy, ΔS° of adsorption were calculated. Water absorption was found to be thermodynamically difficult due to the diffusion mechanism of the process and it was accompanied by a decrease in the values of ΔH° and ΔS° with an increase in fillers contents. The effects of the amount of absorbed water, temperature, and treatment time on the composites tensile properties were estimated.