排序方式: 共有24条查询结果,搜索用时 15 毫秒
1.
2.
将累托石(REC)有机化处理后通过熔融插层复合法制备了REC/热塑性聚氨酯弹性体(TPUR)纳米复合材料,并用傅立叶变换红外光谱仪(FTIR),X-射线和扫描电镜(SEM)等进行了表征。研究结果表明:十二烷基芳基季铵盐(C12)对REC的处理效果及在TPUR中的分散性优于十六烷基季铵盐(C16)和联苯胺(BZD);少量有机化处理REC(分别记作C12-REC,C16-REC和BZD-REC)加入TPUR就可使复合材料的力学性能大幅度提高,其中C12-REC/TPUR的拉伸和撕裂强度在2 wt% C12-REC含量时分别由38.87 MPa和92.8 kN/m提高到57.93 MPa和123.37 kN/m ,增幅分别达49 %和33 %;初步考察了有机化处理条件对力学性能的影响,结果发现:用处理2h的REC制备的纳米复合材料性能最佳。 相似文献
3.
采用十二烷基二甲基卞基氯化铵(DBDA) 和间苯二甲胺(MXDA) 设计并制备了一种新型有机化改性蒙脱土(MMT Ⅱ), 通过球磨法来促进其在环氧树脂中的细化与分散, 制备出具有良好解离结构的MMT Ⅱ/ 环氧纳米复合材料。利用红外光谱(FTIR) 、X-射线衍射(XRD) 和透射电镜( TEM) 表征了新型MMT Ⅱ及其纳米复合材料的结构, 测试了力学性能。结构表征与分析表明, 大颗粒粘土聚集体并不能在搅拌混合过程中分散开, 在固化过程中很难充分解离, 而通过球磨过程中产生的剪切力可促进其分散与细化, 从而获得良好解离结构。MMTⅡ中MXDA 的引入, 减少了季铵盐分子链所产生的悬键, 增加了MMT Ⅱ片层的界面反应性, 大大提高了纳米复合材料的力学性能, 冲击强度由3211kJ / m2 提高到4811 kJ / m2, 提高近50 %, 弯曲强度提高近8 %。 相似文献
4.
5.
采用EPN核壳纳米橡胶粒子对双氰胺固化环氧树脂进行增韧改性。通过傅里叶变换红外光谱(FT-IR)法和扫描电子显微镜(SEM)法表征了EPN的化学结构和表面形貌;使用扫描透射电镜(TEM)表征了EPN粒子在环氧树脂中的分散状态;通过黏度、差示扫描量热分析(DSC)法以及动态热机械分析仪(DMA)表征了EPN粒子对体系流变性能、反应活性以及耐热性的影响;通过树脂浇铸体的冲击强度、复合材料的I型层间断裂韧性(GIC)与冲击后压缩强度(CAI)研究了EPN粒子对树脂及其复合材料韧性的影响。研究结果表明:EPN粒子表面含有大量活性官能团,与环氧树脂间具有良好的相容性,能够以纳米尺寸分散在环氧树脂中;EPN粒子表面的活性官能团能够与环氧树脂反应,添加EPN粒子体系的黏度能够满足材料工艺需求。EPN粒子对环氧树脂具有良好的增韧效果,6%左右的添加量即可使树脂基体的冲击强度达到51 kJ/m2以上,较增韧前提高了130%,同时对体系的Tg无明显影响。复合材料韧性研究结果表明,添加EPN质量分数为6%的复合材料的GIC和CAI均提高了60%以上,具有显著的增韧效果。 相似文献
6.
7.
8.
To further investigate the influence of organic modifiers (primary amine with catalytic hydrogen and quaternary alkylammonium salt) on exfoliation behavior of clay tactoids, high-speed emulsifying and homogeneous mixing(HEHM) and ball milling were used to exert external shearing force on two organic clay tactoids (termed as MMTDDA and MMTDBDA, respectively), which were organically modified with DoDecyl Amine(DDA) and Dodecyl Benzyl Dimethyl Ammonium chloride(DBDA), respectively. The effects of external shearing force on microstructure and properties of both resultant nanocomposites were investigated by X-ray diffractometry(XRD), transmission electron microscopy(TEM) and thermogravimetric analysis(TGA). The results show that whether the clay tactoids are organically modified with catalytic primary amine or quaternary alkylammonium salt, the large agglomerates will not be finely dispersed or exfoliated by conventional mixing (magnetic stirring). After being vigorously sheared by HEHM or ball milling, the dispersion and exfoliation of clay tactoids are increasingly promoted for both MMTDDA and MMTDDA, and the mechanical properties of the high-performance epoxy/clay nanocomposites are enhanced. For epoxy/MMTDDA nanocomposites, impact strength can be increased up to 44.5 kJ/m^2 from 32.1 kJ/m^2, which is about 39% higher than that of pristine matrix, and the flexural strength is enhanced by about 4%. A similar enhancement for epoxy/MMTDBDA nanocomposites has also been achieved. Improvement on thermal stability of epoxy/clay nanocomposites is dependent on the exfoliation of clay layers and molecular structure of the modifiers. The onset temperature is increased with the clay loading decreasing from 5% or higher content to 3% (mass fraction), and the DBDA modifier with the heat-resistant benzyl may also improve the stability of epoxy/MMTDBDA nanocomposires. 相似文献
9.
10.