改性芳纶纬编增强体复合材料力学性能的研究

为探讨芳纶纬编增强体复合材料的力学性能,以对位芳纶为原料,采用LiCl/无水乙醇溶液对芳纶表面进行改性处理,设计并编织1+1满针罗纹和罗纹空气层2种组织织物增强体,以E-51环氧树脂为基体,应用手糊成型技术制备芳纶纬编增强体平板复合材料。采用YG026D型电子织物强力机对制备的芳纶纬编增强体复合平板材料的经纬向拉伸、弯曲、压缩以及层间剪切性能进行测定。结果显示:经LiCl/无水乙醇络合溶液处理的芳纶纬编增强体复合材料的各项力学性能均有所提高,且经向的各项力学性能优于纬向。在拉伸、弯曲性能方面,罗纹空气层芳纶纬编增强体平板复合材料优于1+1满针罗纹芳纶纬编增强体复合材料。     

基于树脂膜溶渗经编多轴向复合材料成型及性能分析

详细阐述了四轴向经编玻璃纤维织物树脂膜溶渗成型工艺,测试了成型后的复合材料性能,并与同样条件下手糊成型工艺进行对比。结果表明:由于树脂膜溶渗成型工艺复合材料中的纤维体积含量要高于手糊成型工艺,因此其试样的断裂强力、断裂伸长率要高于手糊成型;另外,树脂膜溶渗成型复合材料试样沿不同取向断裂强力由高到低分别是经向、斜向、纬向;经真空辅助成型制备的材料相比手糊成型具有较优异的韧性。     

芳纶/碳纤维混杂机织复合材料的力学性能研究

分别以芳纶和碳纤维(CF)为经、纬向纱,采用小样织机制备了不同经纬密度的芳纶/CF混杂平纹织物;以环氧树脂为基体,采用真空辅助树脂转移成形方法制备芳纶/CF混杂织物增强复合材料(简称复合材料);分析了复合材料的力学性能。结果表明:在经向纱(简称经纱)、纬向纱(简称纬纱)的纤维种类分别相同时,复合材料的弯曲强度随经向密度增大而增大;以芳纶为经纱时,复合材料的弯曲模量和拉伸模量随着经纱的密度增大而减小,而复合材料的拉伸强度和断裂伸长率随着经纱密度的增大而增大;以CF为经纱时,复合材料的弯曲模量随着经纱密度的增大而增大,且弯曲强度和弯曲模量均高于以芳纶为经纱时的复合材料。     

汽车装饰面料用阻燃涤纶拉伸变形丝的加工工艺

探讨了不同假捻变形工艺路线下,阻燃涤纶假捻变形丝(DTY)的各项物性指标的变化规律。结果表明:阻燃涤纶DTY的拉伸强度、断裂伸长率、卷曲收缩率和卷曲稳定性均低于同规格的常规涤纶DTY;影响卷曲收缩率和卷曲稳定性的主要工艺参数是变形温度;改变工艺路线,采用S+Z合股的工艺路线,可以大幅度提高阻燃纤维的拉伸强度、断裂伸长率、卷曲收缩率和卷曲稳定性,以适应不同风格的汽车装饰面料的要求。     

2．5 D织物结构与拉伸性能的研究

介绍了2．5D浅交弯联、浅交直联单元结构模型和纤维体积分数计算方法的建立。在此基础上设定一定的织物参数,对其复合材料拉伸性能进行了测试,分析两种结构拉伸性能的差异。通过试验可知：浅交直联经向模量和强度均大于浅交弯联经向性能,浅交弯联的纬向拉伸强度、模量大于直联的纬向性能。浅交弯联的经向强度及模量低于纬向,浅交直联的经向拉伸强度高于纬向拉伸强度。     

整体中空夹层复合材料弯曲刚度研究

基于整体中空夹层复合材料的织物结构特点以及对经纬向弯曲变形现象的分析,建立两种夹层梁模型,分别推导了经向与纬向弯曲刚度的解析表达式。通过理论解、有限元解以及试验值的对比,验证了模型的合理性和准确性。在此基础上,运用本文理论方法探讨了纱线密度对整体中空夹层复合材料弯曲刚度的影响。研究表明,随着纱线密度的增加,整体中空夹层复合材料经纬向弯曲刚度均呈线性增加;经向弯曲刚度的影响因素按影响程度从大到小依次为经纱、绒经、纬纱;纬向弯曲刚度的影响因素按影响程度从大到小依次为纬纱、经纱、绒经;和纬向弯曲相比,绒经对经向弯曲刚度的影响更大。     

大隔距覆增强结构柔性空间膜材料的制备及力学性能

针对提高大隔距柔性膜材料力学性能的迫切需求，通过在大隔距经编间隔织物两表面复合具有增强结构的高分子层，得到大隔距覆增强结构柔性空间膜材料(UGFM)，采用控制变量法，分别测试高分子层有增强结构和无增强结构的UGFM撕裂、剥离、间隔向拉断力等力学性能。结果表明，UGFM表面复合的高分子层在引入增强结构后对其力学性能的影响较大。采用面密度为150 g/m²的机织物作增强结构时，UGFM的经向剥离性能降低了约47.7%，纬向剥离性能降低了约51.0%，经向撕裂性能提高了约37.9%，纬向撕裂性能提高了约30.8%，同间隔距离下间隔向拉伸性能提升了约5.8%。最后探讨了具有增强结构的高分子层对UGFM力学性能影响的机理，UGFM经纬向撕裂和剥离性能的差异化特征主要受间隔织物表面组织结构影响，若破坏失效方向与线圈平行，则失效趋势迅速，若不平行，则失效趋势放缓。同时UGFM间隔向拉伸断裂性能主要受织物间隔距离影响较大，有无增强结构对UFGM间隔向拉伸性能影响微弱。     

高含量玻璃纤维增强PA66/PA6I复合材料的制备及性能研究

采用双螺杆挤出机制备了高含量玻璃纤维增强聚酰胺66 (PA66)/聚间苯二甲酰己二胺(PA6I)复合材料,对不同配比的复合材料进行了表面性能、成型收缩率、吸水率、热变形温度、力学性能的研究。结果表明,添加PA6I可以有效改善复合材料的表面性能,当PA6I含量大于10%时,复合材料表面浮纤消失;复合材料的成型收缩率、吸水率、热变形温度均随着PA6I含量的增加而降低,复合材料的力学性能随着PA6I含量的增加先增加后降低;当PA6I含量为10%时,复合材料的拉伸、弯曲、缺口冲击性能均达到最大值。     

探究不同因素对单轴向玻璃纤维经编织物增强复合材料性能的影响

主要从玻璃纤维增强材料的角度出发,研究了不同的纱线规格,不同的织物克重和不同的织物成型工艺对复合材料力学性能的影响。研究结果表明:针对0°单轴向玻璃纤维织物增强的复合材料,玻璃纤维纱线的本身模量与复合材料最终的力学性能存在正相关的联系,但与±45°方向的剪切性能没有必然的的联系。增加0°主纱方向的克重,有利于增强0°拉伸和压缩性能,但是当克重增加到一定程度时,0°拉伸和压缩性能基本保持稳定状态。不同的缝编针数成型的玻璃纤维织物对复合材料力学性能基本没有影响。     

捆绑纱对预定向经编织物性能的影响

通过用玻璃纤维／涤纶捆绑纱及不同经编组织结构,研究捆绑纱对预定向经编织物性能的影响。结果表明,玻纤可用于捆绑纱组织中,其编织后强度比涤纶纱高33．3％。玻纤捆绑纱可改善树脂对织物的浸渍性,降低最终复合材料的孔隙率,提高复合材料的拉伸和剪切等力学性能。不同的捆绑纱组织结构对复合材料的力学性能影响显著,玻纤做捆绑纱时,经平组织比编链组织复合材料的经向拉伸强度高7．97％,弯曲强度高约5％。     

乙苯,苯乙烯的生产及合成乙苯,苯乙烯催化剂的研究进展

苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况，合成乙苯，苯乙烯所用的催化剂种类，并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。     

Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile

Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, ¹³C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc.     

生物质气化及生物质与煤共气化技术的研发与应用

总结了生物质原料的特点及生物质单独气化的缺点;介绍了国内外生物质气化技术及生物质与煤共气化技术的研发与应用现状;分析了在此领域国内外的发展趋势与前景;概括了开展生物质与煤共气化技术研发的意义。     

Electronic structures and reactivities of monometallic and bimetallic clusters of Au and Cu

The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu₃Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu₃Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters.     

钾盐资源及钾肥供需情况分析及预测

阐述了国内外钾盐资源及钾肥生产现状,对国内外钾盐的供需形势进行了分析及预测,从资源、原材料、国际市场三方面提出了解决我国钾盐短缺的措施。     

Kinetics and Mechanism of Oxidation of Mono- and Polyacetals

Abstract

Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed.     

Comparison of the Adhesion and Cohesion of Triblock and Random Copolymers of Styrene and Butadiene

A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength.     

责任和责任心的涵义与结构

责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体.     

二甲基二烯丙基氯化铵和丙烯酰胺的合成及应用

用复合引发体系(过硫酸盐-偶氮类引发剂)和脂肪胺类氧化还原体系引发,在实验室获得了单体转化率≥98%,特性粘数高于13.6 dL/g的阳离子共聚物PDA,探讨了控制聚合物分子量的影响因素.     

Wetting properties of homopolymers and copolymers of pentafluorostyrene and methylacrylate and homopolymer blends

Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method¹ was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity.