Adhesion of PBO Fiber in Epoxy Composites

The high mechanical and thermal performance of poly p-phenylene- 2, 6-benzobisoxazole ( PBO ) fiber provides great potential applications as reinforcement fibers for composites. A composite of PBO fiber and epoxy resin has excellent electrical insulation properties, therefore, it is considered to be the best choice for the reinforcement in high magnetic field coils for pulsed magnetic fields up to 100 T.However, poor adhesion between PBO fiber and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fiber preventing efficient chemical bonding in the interface, which is a challenging issue to improve mechanical properties. Here, we report the surface modification of PBO fibers by ultraviolet (UV)irradiation, O2 and NH3 plasma, as well as acidic treatments. The interfacial adhesion strength values of all the treatments show the similar level as determined for aramid fibers by pull-out tests, a significant impact on fibermatrix-adhesion was not achieved. The surface free energy and roughness are increased for both sized and extracted fibers after plasma treatments together with maleic anhydride grafting. The sized fiber shows marginal improvement in adhesion strength and no change in fiber tensile strength because of the barrier effect of the finish.For the extracted fiber, different surface treatments either show no apparent effect or cause reduction in adhesion strength. Atomic force microscopy (AFM) topography analysis of the fracture surfaces proved adhesive failure at the fiber surface. The fiber surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fiber surface has no adequate wetting and functional groups. The adhesion failure is further confirmed by similar adhesion strength and compression shear strength values when the fiber was embedded in various epoxy resins with different temperature behavior. The tensile strength of fiber is sensitive to surface treatment conditions as revealed by a bimodal Weibull statistical distribution analysis. Considerable strength reduction occurred, particularly for cases of acidic and plasma treatments, while UV irradiation shows the better ability to retain fiber strength.     

BnHn＋4型和BnHn＋6型硼烷的拓扑指数及其结构

探讨了硼烷拓扑系数的结构关系一些规律，提出在ＢｎＨｎ＋４型硼烷分子（ｎ＝４￣１０）拓扑结构中，具有相同数目的氢桥键和Ｂ－Ｂ键，不存在－ＢＨ２基因，分子拓扑结构主要决定于闭合三中心键数目，对Ｌｉｐｓｃｏｍｂ的拓扑理论进行了拓展，提出了稠合Ｂ－Ｂ键的概念，采用五元组数（ｓ ｘ ｙ ｔ ｚ）来描述硼烷分子的拓扑指数和结构。拓展后的拓扑理论适用于ＢｎＨｎ＋４型ＨｎＨｎ＋６型的低级硼烷和高级硼烷。     

1, 3-dioxolane pretreatment to improve the interracial characteristics of a lithium anode

1,3-dioxolane （DOL） was originally used to pretreat a lithium metal electrode to improve its interracial characteristics. Electrochemical impedance spectra （EIS） measurements revealed that, after the DOL pretreatment, the lithium electrode had better interfacial stability during immersion in electrolyte and as repeated charge/discharge cycles. It was proved by SEM that the pretreated one has smoother morphology and less dendrite after repeated charge/discharge cycles. Consequentially, benefiting from the better interface characteristics of the lithium electrode.     

固化条件对环氧玻璃鳞片涂层硬度的影响

研究了固化条件对添加玻璃鳞片的环氧胶粘涂层硬度的影响,结果表明,当玻璃鳞片的含量在20%~30%的范围下变化时,经80℃加热1 h的环氧玻璃鳞片涂层有较高的硬度;而在60℃加热1h的固化条件下,玻璃鳞片的含量对涂层的硬度无显著影响.     

环氧砂浆法处理合肥市董铺水源泵房混凝土池体裂缝的几点心得体会

董铺水源泵房是合肥市重点工程之一，我作为建设方代表全程参与了其工程施工的全过程。在浇注池壁时由于施工组织不当，二次砼浇捣时间超过砼初凝时间，使二次浇捣处产生了施工冷缝，而施工缝处又未采用新型防水材料处理，结果工程竣工后发现池壁有渗漏水现象。为了处理这些裂缝，建设单位和施工单位比较了多种措施，最后决定采用环氧砂浆法处理。本人经过几年的观察，发现效果比较好，未出现渗漏水现象。该方法简单适用，效果好，有一定适用价值，故本人将上述处理方法进行总结，供大家共同参考，具体如下：     

吐哈盆地油砂连续抽提地球化学研究及其意义

通过对吐哈盆地7个油砂样连续抽提研究，结果表明自由态组分、油气包裹体和黏土吸附油气组分分子地球化学特征具有明显的差异．油气包裹体和黏土吸附油气组分具有明显的湖相泥岩地球化学特征：(1)较高的Ph/nC18比值和较低的Pr／Ph比值；(2)较高的C26三环萜烷／C24四环萜烷、C23三环萜烷／(C23三环萜烷 C3017α(H)藿烷)、C21／(C21 ∑C29)甾烷、Ts／Tm和C29Ts／C2917α(H)降藿烷比值和较低的C19／C21三环萜烷比值；(3)相对较高的C27和C28规则甾烷含量和较低的C29规则甾烷和重排甾烷含量．表明早期注入这些油层的油气组分来源于前侏罗系湖相泥岩，晚期注入的油气组分来源于侏罗系煤系地层或煤岩。     

南京长江二桥的设计与施工

本文主要介绍了我国跨径最大的斜拉桥-南京长江二桥设计和施工过程中的一些技术问题,环氧沥青混凝土铺装层的应用开辟了在我国应用的先河,也为在其它桥梁上应用奠定了基础.     

硝酸吗啉催化2,10-环氧蒎烷液相重排合成紫苏醇

研究硝酸吗啉催化的2,10-环氧蒎烷液相重排反应及其产物分布规律,主要考察了催化剂用量、反应温度和反应时间对主要产物分布的影响.实验结果表明:在硝酸吗啉催化剂存在下,2,10-环氧蒎烷液相重排主要生成紫苏醇和桃金娘烯醇,产物中紫苏醇含量达65%~74%,适当升高反应温度或延长反应时间有利于紫苏醇的生成;确定了2,10-环氧蒎烷液相重排合成紫苏醇的优化条件为:催化剂用量为2,10-环氧蒎烷投料量的10%(摩尔)反应物与溶剂的体积比为1∶4,在313~318 K下反应2 h,紫苏醇产率可达74%;并对提出的反应机理进行了讨论.     

环氧亚麻油增塑剂合成方法的研究

报道了一种以磷酸为催化剂，甲酸、H2O1为原料对亚麻油进行环氧化的新方法。结果表明：用磷酸作催化剂优于树脂，甲酸作过氧化剂优于冰醋酸；反应条件温和，具体操作简便，使反应时间缩短；产物符合环氧亚林油增塑剂标准，环氧值？7．8％，碘值＜10。