【作者】 史建华；

【导师】 赵仁；

【作者基本信息】 中北大学 ， 武器系统与运用工程， 2014， 博士

【摘要】 静电防护在炸药、武器弹药生产和使用中尤为重要，在军工生产领域的建筑设施内主要采用导电橡胶作为防静电的材料。军用导电橡胶生产本高，同时导电橡胶只有在受到一定压力时，导电颗粒相互接触，才具有良好的导电性。军工生产厂房的建筑多采用水泥材料，若能够使水泥具有一定的导电性，铺设在厂房地面、工作台面及一些非承载墙体，既可有效提高静电防护能力，又可大大降低建筑生产成本。制备接地效果明显、耐久性好、无污染、经济、轻便的导电水泥材料已成为科研工作者们共同关注的问题，针对这一问题，本论文通过理论研究、科学实验和数值分析相结合，研究了发泡石墨-水泥导电复合材料制备的原理、工艺和导电、发热机理，通过大量试验研究了影响导电水泥电学性能和物理性能的因素，得出了制备发泡石墨-水泥导电复合材料的方法及掺料的最佳比。由于石墨的加入会大大地降低水泥基体强度，因此，需要在加入石墨同时还需加入某种纤维进行强度增强。本文选用物理力学性能较好的玄武岩纤维材料，在水泥砂浆中均匀地掺入玄武岩纤维材料来提高复合水泥材料制品的抗拉强度抗裂强度和韧性。为了降低导电水泥的密度，本文选用了两种途径，一是在石墨-水泥中添加聚苯乙烯颗粒，二是采用物理发泡法和双氧水化学发泡法对石墨-水泥浆料进行发泡。因此，本文首先采用石墨作导电相，水泥作胶凝材料制备密实型石墨-水泥导电接地模块，考察了不同石墨含量的添加对复合材料力学性能和电学性能的影响；接着通过在石墨-水泥浆料中添加聚苯乙烯颗粒和玄武岩纤维来实现降低试件密度和增强试件强度，得到了聚苯乙烯颗粒和玄武岩纤维的最佳添加粒径和最佳添加量；然后采用物理发泡方法研究高性能、轻质量导电水泥接地材料的制备工艺；最后采用聚乙烯醇、十二烷基磺酸钠及聚乙烯吡咯烷酮作稳泡剂进行双氧水化学发泡来制备轻质量的导电水泥接地模块，并对它们的电阻率、抗压强度、抗折强度及干密度作了进一步比较。主要结果和结论如下：1研究了不同石墨含量的添加对水泥基复合材料电阻率、抗压强度、抗折强度及干密度的影响。结果表明：1)掺入石墨的导电水泥，导电性与石墨掺量有关，石墨掺量越大，导电性越好，但石墨掺量过大反而会严重影响材料的强度。为了保证导电水泥的强度，石墨掺量不能过大。2)当石墨掺量加大时，密实型石墨-水泥导电复合材料的电阻率和干密度虽有显著降低，但同时也导致材料抗压强度和抗折强度的降低。当石墨含量为50%时制备的导电水泥接地材料具有较好的力学性能和电学性能。2固定石墨掺量为50%，考察聚苯乙烯颗粒和玄武岩纤维的添加对导电水泥力学性能和电学性能的影响。结果表明，当石墨掺量为50%时，以掺入1~2mm聚苯乙烯颗粒和2.5%玄武岩纤维的导电水泥的物理性能最佳。3采用物理发泡法制备的石墨-水泥导电接地试样，硬化凝结时间较长，内部结构表现为：孔径小、大小均匀、球形度高、强度高、泡孔间连通率低。4采用双氧水化学发泡法制备的石墨-水泥导电接地复合材料的电阻率、抗压强度、抗折强度及干密度均随掺入聚合物品种不同而差异较大。其中，在石墨掺量为50%的条件下，当采用聚乙烯吡咯烷酮作稳泡剂配制而成的发泡剂发泡时形成的气孔细小，呈球型封闭且孔径分布均匀，可减小应力集中，提高材料的力学性能。相同试验条件下，采用聚乙烯醇和十二烷基磺酸钠制备而成的石墨-水泥导电接地复合材料，发泡后浆料凝结时间与气泡稳定时间不同步，导致气泡长大后破裂，降低了材料的力学性能和电学性能。更多还原

【Abstract】 The electrostatic protection is particular important in the process of production and theusing of explosive and ammunition, and also in the building for militaryproduction, conductive rubber as antistatic materials is widely used. Military conductiverubber is of high production costs, and only under a certain pressure can the conductiveparticles contacting each other, and in this way the conductive rubber expresses goodconductivity. Cement materials are widely used in the buildings of military production plants,if the cement which has certain conductivity is used in the plant ground, working tables andsome non-bared walls, it can not only improve the antistatic ability effectively, but also canreduce the construction cost greatly. Making a cement material of obvious ground effect, gooddurability, no pollution, being economic and light has become the common concern issue toscientific workers. For solving this problem, theoretical research, science experiments andnumerical analysis were all used in this paper to study the preparation principle, process andconductivity, heat mechanism of foam graphite-cement conductive composites. Through alot of tests, the factors that have effect on electrical conductivity and physical properties ofcement were studied, the method of preparing foam graphite-cement conductive compositesand the best mixture ratio were also obtained.Due to the addition of graphite, the intensity of the cement matrix greatly decrease,therefore, it’s necessary to add some fiber to increase the strength of the cement matrix. Thebasalt fiber with good physical and mechanical performance was selected in the paper. Thestrength, crack resistance and toughness of the cement product will be dramaticallyenhanced by adding basalt fiber into the cement mortar. In order to reduce the density of theconductive cement, two methods were chosen. One is to add the polystyrene particles intothe conductive cement; the other is to deal with the graphite-cement slurry using thephysical foaming method and hydrogen peroxide chemical foaming method. So, in thepaper, first, the dense graphite-cement conductive ground module was prepared with graphite as conductive phase, cement as cementing materials, and the influence of differentgraphite content on the mechanics performance and electrical performance of the compoundmaterial was studied. Then, the polystyrene particles and basalt fiber were added into thegraphite-cement slurry to reduce the density and enhance the strength of the specimen. Thebest size and amount of the polystyrene particles and basalt fiber were determined. Third,the preparation technology for high performance, light quality conductive cement groundmaterial by physical foaming method was studied. Last, the light quality conductive cementground module was prepared by hydrogen peroxide chemical foaming method usingpolyvinyl alcohol, sodium dodecyl sulfate and polyethylene pyrrolidone as stable foamagent. The resistivity, compressive strength, flexural strength and dry density werecompared. The main results and conclusions are as follows:1The effect of adding different content of graphite on the resistivity, compressivestrength, flexural strength and dry density of cement base composite materials was studied.The results show that:1) The electrical conductivity of graphite-cement composite material is related to thegraphite content. The more the graphite content, the greater the conductivity, but thegraphite content will affect the strength of the material, so the graphite content also cannotadd too much in order to keep the strength.2) With the increase of graphite content, the resistivity and dry density of the densegraphite-cement conductive composites is significantly reduced, but also causes materialcompressive strength and flexural strength reduced. When the graphite content is50%, theprepared conductive cement ground material has good mechanical properties and electricalproperties.2The effect of adding different polystyrene particle and basalt fiber on mechanicalproperty and electrical property of the conductive cement was investigated under fixing50%graphite. The results show that, when the graphite content is50%, the physicalproperty of the conductive cement with mixed1~2mm polystyrene particles and2.5%basalt fiber is the best. 3The setting time of graphite-conductive cement ground sample by physical foamingmethod is long. The internal hole with the same size is small, the spherical degree is high, theconnectivity rate between bubble holes is low, and the intensity is high.4The resistivity, compressive strength, flexural strength and dry density of the graphite-conductive cement composite material prepared by hydrogen peroxide chemical foamingmethod are varied with the doped polymer variety.Under the condition of graphite, content is50%. When using polyvinylpyrrolidone asstable foam agent, the getting stomata is tiny. The pore size distribution is uniform whichcan reduce the stress concentration, increase mechanical property of the material. At thesame experimental conditions, the setting time and bubble stability time of the graphite-conductive cement composite material prepared by the polyvinyl alcohol and sodiumdodecyl sulfate are not synchronized, that lead to bubbles burst after growing up and reducethe mechanical property and electrical property.更多还原