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氯化聚丙烯与丙烯睛及苯乙烯基二乙氧基硅烷接枝共聚胶粘剂研究 总被引:6,自引:0,他引:6
邹丽霞 《华东地质学院学报》1997,20(4):380-383
本文介绍了以低含氯量的氯化聚丙烯与不同比例的丙烯睛及苯乙烯基二乙氧基硅烷,在溶液中及引发剂存在下,经自由基接枝共聚反应制得胶粘剂。实验结果证明:这种胶粘剂不仅对聚丙烯材料有优良粘接性,对钢、铝等材料也有十分理想的粘接效果。 相似文献
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冻融作用下PPF稳定土力学性能研究 总被引:4,自引:4,他引:0
为了研究冻融作用下外加材料稳定土的力学性能,以一种国产土壤固化剂(TG固化剂)加固低剂量水泥石灰稳定土为研究对象,通过冻融前后的无侧限抗压强度试验、劈裂强度试验和抗压回弹模量试验,研究不同压实度、聚丙烯纤维(PPF)掺量稳定土的力学性能。结果表明:稳定土的抗压强度、劈裂强度及回弹模量均随冻融次数的增加而降低,经历6次冻融循环后,强度、模量损失率基本稳定。冻融前后稳定土的抗压强度、劈裂强度、抗压回弹模量以及强度、模量的残留百分比均随着压实度和PPF掺量的提高而增大。结合工程实际情况,选取压实度为95%,0.2% PPF综合稳定土进行冻融试验,得到抗压强度残留比(BDR)达到59.32%,质量变化率仅为6.28%,研究表明,PPF综合稳定土具有优良的冻稳定性,可用作路面基层材料。 相似文献
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One of the causes of heavy damage due to earthquake motions is the role of soft clay in amplifying bedrock ground motions. Improving the soil conditions using polypropylene fibres at a site in order to mitigate earthquake damage could be one of the methods to modify site conditions. In this study, the optimum fibre contents were obtained for mixtures of clay with two different types of fibre. Then the dynamic properties of polypropylene fibre reinforced clay with different fibre contents were determined using resonant column testing. The study showed that the inclusion of fibre at optimum fibre content can improve the dynamic properties of clay at the low shear strains used. Test results indicated that both the shear modulus and damping increased. Hence, the inclusion of fibre in clay can provide a double benefit for the dynamic response of a site by increasing the stiffness of the site and reducing its amplitude of vibration. 相似文献
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软岩巷道聚丙烯混凝土钢筋网壳复合衬砌试验及工程应用研究 总被引:1,自引:0,他引:1
根据大跨度空间壳体力学原理,研究聚丙烯网壳锚喷支护新技术。其技术特色是用一种在地面加工成型的特殊三维钢筋支架代替普通的二维钢筋网,大幅度提高了锚网喷结构的支撑能力,不需要使用型钢支架、锚索、围岩注浆等手段进行加固就能有效地支护高地压大变形巷道、跨采动压巷道、冲击地压巷道以及大断面硐室等。依托西山煤电集团大巷破碎段修复工程,完成了聚丙烯纤维混凝土钢筋网壳复合衬砌支护结构的室内模型试验,研究了复合衬砌的变形、破坏形态与发展规律。现场应用表明,在不降低支护的承载能力的情况下,与重型金属支架相比,该支护形式降低了钢材用量和混凝土回弹量,且具有良好的柔性,是软岩巷道一种优良的让压支护结构,具有较好的推广应用前景。 相似文献
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C Kosore L Ojwang J Maghanga J Kamau A Kimeli J Omukoto 《African Journal of Marine Science》2018,40(3):225-234
Microplastics can be ingested by marine organisms and may lead to negative impacts at the base of marine food chains. This study investigated the occurrence and composition of microplastics in the sea-surface water and sought evidence of ingestion by zooplankton. Surface seawater was collected using a stainless-steel bucket and sieved directly through a stainless-steel sieve (250-µm mesh), while a 500-μm mesh net was towed horizontally to collect zooplankton, at 11 georeferenced stations off the Kenyan coast in February 2017, on board the national research vessel RV Mtafiti. Microplastic particles were sorted and characterised using an Optika dissecting microscope. Polymer types were identified using an ALPHA Platinum attenuated total reflection—Fourier-transform infrared (ATR-FTIR) spectrometer. A total of 149 microplastic particles, with an average abundance of 110 particles m–3, were found in the surface seawater. A total of 129 particles were found ingested by zooplankton groups, where Chaetognatha, Copepoda, Amphipoda and fish larvae ingested 0.46, 0.33, 0.22 and 0.16 particles ind.–1, respectively. Filaments dominated both the surface-water microplastics and the ingested microplastics, contributing 76% and 97% to those compositions, respectively. White particles were prevalent in the water (51%), whereas black was the colour found most commonly (42%) across the zooplankton groups. The sizes of particles that were in the water were in the range of 0.25–2.4 mm, and those ingested ranged between 0.01 and 1.6 mm. Polypropylene was predominant in the surface water, whereas low-density polyethylene was the most-ingested polymer type. The results provide the first documented evidence of the occurrence, composition and ingestion of microplastics by zooplankton in Kenya's marine environment, indicating that microplastics have the potential to enter pelagic food webs and cause pollution in the study area. 相似文献
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通过3个聚丙烯纤维增强混凝土异形柱边节点和1个普通混凝土异形柱边节点的低周反复荷载试验,对比研究了聚丙烯纤维增强对混凝土异形柱节点抗震性能的影响。结果表明:采用聚丙烯纤维增强可以提高节点的开裂荷载和变形能力,减小核心区内裂缝的数量和宽度,延缓构件的刚度退化,减轻节点的累积损伤程度,有效改善节点的破坏形态,有利于节点抗震。 相似文献
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传统的碱解扩散分离-酸碱滴定法测定土壤样品中的水解性氮,通常采用玻璃扩散皿进行碱解扩散分离。但是使用该法对样品进行前处理和碱解扩散分离过程中,操作者常会面临如下三种困扰:一是玻璃扩散皿内室溶液极易被氢氧化钠溶液和碱性胶液污染;二是玻璃扩散皿和盖子之间容易出现氨气泄漏,而且发现时往往无法解决;三是玻璃扩散皿比较笨重易碎,实验操作不方便;最终导致测定结果不稳定性和操作者对该法体验不佳。本文采用聚丙烯扩散皿,通过改进扩散皿清洗方法和提升扩散皿密封性、统一还原剂加入量和氢氧化钠溶液浓度(1.8mol/L)、适当增加氢氧化钠溶液的加入体积和降低盐酸标准溶液浓度,提高了水解性氮测定的稳定性和准确性。该方法中发生的污染明显降低,避免了发生氨气泄漏,操作便捷。应用于分析土壤有效态标准物质的测定值与标准值一致,如水解性氮测定值< 50mg/kg的标准物质GBW07416a,其绝对偏差为0.2~1.8mg/kg;水解性氮测定值在50~200mg/kg的标准物质GBW07415a、NSA-1、NSA-4、NSA-5、NSA-6,其绝对偏差为0~4.0mg/kg。还原剂对硝态氮转化为铵态氮的加标回收率在89.6%~96.4%之间。该方法可满足测定土壤样品中水解性氮含量的要求。 相似文献
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聚丙烯纤维低弹模混凝土以其优良的工作性能和力学性能成为近年来我国水利工程大坝防渗墙采用的主要材料之一.在室内试验的基础上,对聚丙烯低弹模混凝土的强度、塌落度特性进行了研究;开发了一套混凝土耐久性渗透水采集仪,对聚丙烯低弹模混凝土的渗透性和耐久性进行了研究,试验结果表明:与传统低弹模混凝土相比,聚丙烯低弹模混凝土的抗压、弹模变化不大,抗拉强度有提高,抗渗性能明显改善,渗透系数降低了一个数量级左右,耐久性年限可以进一步提高,研究结果为聚丙烯低弹模混凝土大坝防渗墙的工程应用提供了技术支撑. 相似文献