【作者】 张英；

【导师】 李祥高；

【作者基本信息】 天津大学 ， 应用化学， 2016， 博士

【摘要】 本论文研究了制约聚合物/粘土纳米复合材料研究领域发展的两个关键问题:一是如何使粘土片层以“高度无规剥离”的形式分散在聚合物基体中;二是如何在聚合物基体与粘土片层之间构建较强的界面作用力。(1)以环氧树脂/粘土体系为研究对象,提出了一种制备聚合物/粘土纳米复合材料的新方法,即“粘土-淤浆复合法”。该方法通过选择带有特殊官能团的有机修饰剂改性粘土,采用“粘土-丙酮淤浆”直接与环氧树脂复合,实现粘土片层在固化反应之前在环氧预聚体中剥离,制备出高度无规剥离结构的环氧树脂/粘土纳米复合材料。(2)用X射线衍射(XRD)跟踪环氧树脂基纳米复合材料制备的各个阶段,结合透射电镜(TEM)观察,阐明有机修饰剂的种类对所形成的纳米复合材料微观结构的影响及粘土片层在环氧树脂中高度无规剥离的机理。2,4,6-三(二甲胺基甲基)苯酚(DMP-30)及Jeffamine 230(D230)带有强吸水性且与环氧预聚体有良好的相容性且具有反应性的官能团,用它们改性的MMT实现了在固化反应之前在环氧预聚体中的无规剥离,制备出高度无规剥离结构纳米复合材料;氯化胆碱(CC)具有较强的吸水性但与环氧树脂的相容性一般,所制备的纳米复合材料为插层与剥离混合结构;憎水性的十六烷基三甲基溴化铵(CTAB)及十八烷胺(ODA)与环氧树脂预聚体相容性较差,形成插层结构的纳米复合材料。(3)研究有机修饰剂的种类对环氧树脂纳米复合材料热性能、摩擦性能以及弯曲性能的影响。结果表明:由带有反应性官能团的修饰剂DMP-30和D230改性的MMT制备的复合材料性能优于非反应性的修饰剂(CTAB和ODA)改性MMT制备的复合材料,而能与基体形成氢键的修饰剂(CC)的改性MMT制备的复合材料性能则处于两者之间。(4)采用带有羟基的CC作为有机修饰剂改性蒙脱土,以叔胺为催化剂,实现了环氧树脂基体与MMT之间的化学反应,在环氧树脂基体与蒙脱土片层之间建立了较强的界面作用力,使环氧树脂/蒙脱土纳米复合材料的玻璃化转变温度提高了13℃,拉伸强度提高了近160%。更多还原

【Abstract】 Two challenging tasks in the field of polymer/clay nanocomposites were explored in the thesis.One is how to obtain highly and disorderly exfoliation of clay in the polymer matrix,the other is how to build a stronger interface between the polymer matrix and the clay platelets.The main results are as follows:(1)A new “acetone-clay slurry compounding” approach has been developed to fabricate epoxy/clay nanocomposites.The chosen modifier with special functional groups was employed to modify pristine Na+-clay.The prepared organoclay-slurry,instead of being dried up as usual,was directly blended with epoxy resin and clay layers were exfoliated in epoxy prior to curing.And then a disorderly and highly exfoliated epoxy/clay nanocomposite was achieved.(2)The effect of different organic modifiers on the microstructure of nanocomposites and the mechanism of exfoliation of the organoclay in epoxy via the new method have been explored by monitoring the change of morphology of organoclay during each stage of processing with X-ray diffraction(XRD)and by TEM observation.When 2,4,6-tris(dimethylaminomethyl)phenol(DMP-30)and Jeffamine 230(D230)used as modifiers,both of which have strong hydrophilic group and reactive group and also have good compatibility with epoxy prepolymer,highly and disordered exfoliation can be formed.In the case of organoclay modified with hydroxyl-substituted quaternary ammonium ions(CC),which has stronger hydrophility but relatively week affinity with epoxy prepolymer,a mixture of ordered and disordered exfoliation can be obtained.When aliphatic alkyl ammonium(CTAB and ODA)used as surfactants,which are hydrophobic and bad in compatibility with epoxy prepolymer,the organoclay usually has a poor dispersion in epoxy and aggregation occasionally formed.They can only lead to a slightly increase in d-spacing but not to an exfoliation.(3)The influences of the type of modifiers on flexural strength,thermal stability and friction properties of epoxy/clay nanocomposites have been investigated.It revealed that the performance of nanocomposites prepared by organoclay(modified by DMP-30 and D230)with reactive functional groups were superior to those of nanocomposites prepared by organoclay modified by CTAB and ODA,which have on reactive functional groups.The related properties of nanocomposites fabricated by CC modified clay,which can form hydrogen bonds with epoxy,are in the moderate level.(4)In order to establish stronger interfacial interaction between organoclay and epoxy matrix,which would help improve the mechanical properties of nanocomposites,CC with hydroxyl group was used to modify the montmorillonite.A chemical reaction takes place between the epoxy and CC-MMT when DMP-30 as a catalyst,and then a strong chemical bonding was built up.The mechanical and thermal properties of epoxy/clay nanocomposite were improved significantly.The glass transition temperature has increased by 13℃,the tensile strength increased by nearly 160%.更多还原