【作者】 张静；

【导师】 张晓虹；

【作者基本信息】 哈尔滨理工大学 ， 高电压与绝缘技术， 2011， 硕士

【摘要】 本文以双酚A型环氧树脂为基体树脂,蒙脱土为无机填料,十八烷基氯化铵和偶联剂KH550为改性剂,甲基六氢邻苯二甲酸酐为固化剂,采用正交试验法优化了复合材料的固化工艺,制备出了不同有机改性蒙脱土以及不同蒙脱土含量的环氧树脂/蒙脱土复合材料。利用傅里叶红外光谱对十八烷基氯化铵与偶联剂KH550处理的蒙脱土的化学成分进行分析,试验研究了不同有机改性剂对与蒙脱土的作用机理。用高阻计测试了复合材料绝缘电阻率的温度特性,用高压西林电桥测试了复合材料介电温度谱特性,用宽频介电谱仪测试了复合材料的介电频率谱特性,重点探讨了蒙脱土的改性及蒙脱土含量对复合材料介电性能的影响。通过对有机化蒙脱土的傅里叶红外光谱分析得到,十八烷基氯化铵与偶联剂KH550均能与蒙脱土相互作用,使蒙脱土由亲水性转为亲油性。对复合材料的测试结果表明,偶联剂KH550改性的蒙脱土(K-MMT)和十八烷基铵盐改性的蒙脱土(O-MMT)均能使环氧树脂(EP)的介电常数(ε)与损耗角正切值(tanδ)降低,特别当温度达到160℃时,K-MMT/EP的ε和tanδ分别下降了5%和35%,而O-MMT/EP的ε和tanδ分别下降了16%和41%。可见,有机化蒙脱土的加入有望提高环氧树脂的耐温等级;对于O-MMT/EP复合材料,当蒙脱土含量为5%时,其介电常数及损耗角正切值最低,常温工频时与纯环氧树脂相比,分别下降了18%与42%。为了进一步分析产生这一现象的产生原因,试验研究了复合材料的松弛时间及分布。其结果显示,蒙脱土含量为5%的复合材料的松弛时间最长,且松弛时间的分布参数最小。此外,将复合材料的松弛时间与材料的电导率进行对比,发现这两者存在某种正比例的关系。更多还原

【Abstract】 Epoxy/organic-montmorillonite nanocomposites were prepared with different organic-montmorillonite and content of montmorillonite by diglycidyl ether of bisphenol A, montmorillonite as inorganic filler, octadecyl trimethyl ammonium chloride and silane coupling agent KH550 as modifying agent, methylhexahydrophthalic anhydride as curing agent. Parameters of the curing process were optimized by the theory of orthogonal experimental design.Chemical composition of different organic-montmorillonite was analyzed by Fourier Transition Infrared(FTIR). The mechanism of interaction effect between different organic modifying agent and montmorillonite was studied. The temperature properties of resistivity of composites was measured by Megger. The temperature dependence of composites dielectric spectrum was verified by using a Schering bridge. The frequency dependence of composites dielectric spectrum was verified by using novocontrol alpha-a. The effects on composites’electric properties caused by different organic-montmorillonite and contents of montmorillonite have been discussed.Whether octadecyl ammonium chloride or the coupling agent KH550, they can interact with the montmorillonite both, through analyzing FTIR spectrum of organic-montmorillonite. The character of the montmorillonite changed from hydrophilic to hydrophobic. The test results of the composite indicated that, inclusion of K-MMT and O-MMT into epoxy matrix can reduce permittivity and dissipation factor. The permittivity and dissipation factor of K-MMT/EP composites respectively reduced 5% and 35%, the permittivity and dissipation factor of O-MMT/EP composites respectively reduced 16% and 41%, when testing temperature is 160℃. It can be confirmed that epoxy improved by organic-montmorillonite is provided with better heat resistance property than those of pure epoxy. As for O-MMT/EP composites, the permittivity and dissipation factor of composites that contains 5wt% O-MMT is lowest. For instance, the permittivity reduced 18% and the dissipation factor reduced 42% than pure epoxy, when it is room temperature and power frequency. For further investigation on this appearance, relaxation time and distribution were tested on epoxy and epoxy/montmorillonite nanocomposites. The results showed that: relaxation time of epoxy/montmorillonite nanocomposites were the longest and distributed parameter is the smallest, when the montmorillonite content was 5wt%. In addition, compare with relaxation time and conductivity of composites, we found they have existed direct proportion relationship.更多还原