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甲基磺酸对PBO纤维的表面改性 总被引:1,自引:0,他引:1
采用甲基磺酸(MSA)溶液对PBO纤维表面进行化学改性,用单丝拔出试验测定了改性前后PBO纤维与环氧树脂基体的界面剪切强度,并通过扫描电镜(SEM)、X-射线光电子能谱(XPS)、接触角分别对处理前后纤维的表面形貌、表面组成以及表面自由能进行了表征.研究结果表明:在甲基磺酸质量分数为60%的溶液中,60℃下处理6 h的PBO纤维与环氧树脂基体的界面剪切强度比未处理的提高了81%,并且纤维表面O元素的质量分数增加了13.3%,表面自由能增加了17.3%.当溶液中甲基磺酸的质量分数、处理时间和处理温度进一步提高时,PBO纤维的皮层将遭受破坏,导致界面剪切强度下降. 相似文献
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近年来,工业界和学术界都将注意力聚焦在可持续天然纤维复合材料的开发上。玄武岩纤维具有高强度、高模量、耐高温、耐酸碱、隔热隔音、热振稳定性好、介电性能优异、绿色无污染及成本低等优点,玄武岩纤维增强树脂基复合材料凭借其优异的机械性能和可设计性被广泛地应用于飞行器、汽车、船舶、建筑、石油化工管道及风力发电机叶片等领域。然而,玄武岩纤维与聚合物基底间差的相容性导致玄武岩纤维增强树脂基复合材料存在诸多缺陷和不足。其中,界面强度不够高、界面相易被破坏的问题成为制约玄武岩纤维增强树脂基复合材料发展的瓶颈之一,因此许多玄武岩纤维增强树脂基复合材料研究工作集中在提高其界面结合能力上。本文介绍了玄武岩纤维增强树脂基复合材料的主要研究方向,以及几种常见的复合材料界面作用机理,并综述了近年来国内外关于玄武岩纤维增强树脂基复合材料界面增强改性方面的研究工作。 相似文献
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树脂基复合材料具有比强度高、比模量大、耐高温、耐腐蚀、质轻等诸多优点,在航天军工、生物医疗、电子封装、体育器材等众多领域得到广泛应用。石墨烯作为一种典型的二维纳米材料,凭借其独特结构以及优异的物理化学性能而备受关注。近年来的研究表明石墨烯可以通过对增强纤维改性和对基体树脂改性的方法来提高树脂基复合材料的力学性能。本文介绍了石墨烯改性树脂基复合材料的增强增韧机理,对石墨烯改性纤维(碳纤维、玻璃纤维、芳纶纤维)增强复合材料以及树脂的改性方法进行了综述;着重阐述了石墨烯改性树脂基复合材料力学性能的研究进展,分析了石墨烯改性树脂基复合材料研究中依旧存在的两大问题,即石墨烯的分散性和界面结合问题,并对石墨烯改性树脂基复合材料的未来发展前景进行了展望。 相似文献
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对Kevlar纤维进行了改性,使其成为己内酰胺阴离子开环聚合的活性中心,采用阴离子接枝法在Kevlar纤维(KF)表面接枝尼龙6低聚物,并与基体尼龙6混合,用挤出和注塑方式制备了尼龙6/改性Kevlar纤维(PA6/KF1)复合材料。ESEM和XPS分析表明,Kevlar纤维表面接枝上了尼龙6低聚物。比较了尼龙6/未改性Kevlar纤维(PA6/KF0)和PA6/KF1复合材料的力学性能及破坏形态,同时探讨了其破坏机理。结果表明,接枝尼龙6的KF1增强了KF与尼龙6复合材料界面的相互作用,拉伸强度、弯曲强度和弯曲模量分别提高了20.69%、12.26%和14.23%,但冲击强度降低了8.2%;当复合材料被破坏时,未改性纤维表面只粘附有少量的树脂尼龙6,而改性纤维的表面有较多的树脂包覆层,呈部分非界面脱粘破坏,具有良好的界面结合能力。 相似文献
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利用空气介质阻挡放电(DBD)等离子体对超高分子量聚乙烯(UHMWPE)纤维进行表面改性处理研究以提高纤维表面的润湿和粘结性能.分别研究了等离子体处理时间及电压对UHMWPE纤维拉伸断裂强力、接触角、表面形貌、表面化学成分和粘结性能等的影响规律.SEM分析结果表明,空气DBD等离子体处理后UHMWPE纤维表面出现垂直于纤维轴向分布的凹坑和裂纹,使得纤维表面粗糙度显著增加.XPS分析表明空气DBD处理后纤维表面碳元素含量显著下降;同时氧元素和氮元素的含量均较处理前增加,但氧元素含量增加的幅度显著高于氮元素.XPS分峰结果表明等离子体处理后UHMWPE纤维纤维表面C—O/C—N基团含量显著增加,同时出现了C O和O—C O这2种新的含氧官能团.同时,接触角及和与环氧树脂之间的界面剪切力(IFSS)测试结果表明DBD等离子体处理后UHMWPE纤维表面润湿性能和粘结力均产生显著提高,且随着等离子体处理时间或电压的增加,UHMWPE纤维的表面润湿性能和粘结力均呈现先上升后下降的趋势.空气DBD等离子体处理对UHMWPE纤维的力学性能影响较小,当处理电压低于200 V,处理时间小于100 s,纤维强力下降比率小于5.2%. 相似文献
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在以结晶性聚合物为基体树脂的纤维或织物增强复合材料中,经常出现横穿结晶(横晶)界面相。本文综述了近年来对纤维增强树脂基复合材料中横穿结晶的研究,内容包括横晶的概念,纤维表面诱导成核的机理,纤维诱导成核的能力和条件,横晶的生长和终止以及横晶的力学效应等。在不同的树脂/纤维复合材料体系中,由于其横穿结晶本身和本体球晶在尺寸和数目比例等方面呈现各不相同的复杂局面,横晶对复合材料性能的影响显得复杂。通过各种手段调控横晶的形态、尺寸及数量,使横晶的存在有利于复合材料整体性能的提高,是进行纤维增强结晶性聚合物基复合材料设计时应该遵循的一个基本原则。 相似文献
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利用手持技术改进测定乙醇分子结构实验 总被引:1,自引:0,他引:1
利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1989,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988. 相似文献
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由于石化行业的生产需要,其材质的使用具有多样性和广泛性,经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识,根据光谱仪的测试能力及标样的采集,实现了一个或几个元素测量范围的扩展,并对其测量的影响因素进行了研究。 相似文献
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Mustafa R. Ibrahim Zacharia A. Fataftah Paul von Ragu Schleyer Peter D. Stout 《Journal of computational chemistry》1987,8(8):1131-1138
Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases. 相似文献
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V. I. Bol'shakova L. I. Demenkova É. N. Shmidt V. A. Pentegova 《Chemistry of Natural Compounds》1988,24(6):691-694
The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae. 相似文献
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Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin
E. I. Kapinus V. A. Ganzha B. M. Dzhagarov E. I. Sagun V. B. Pavlenko 《Theoretical and Experimental Chemistry》1989,25(2):146-151
The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989. 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献