异氰酸酯功能化碳纳米管/热塑性聚氨酯弹性体复合材料的制备及流变性能

Preparation and Rheological Properties of Isocyanate Functionalized Carbon Nanotubes/Thermoplastic Polyurethane Elastomer Composites

中文关键词: 碳纳米管 异氰酸酯 表面修饰 热塑性弹性体 流变性能

英文关键词: carbon nanotubes, isocyanate, surface modification, thermoplastic elastomer, rheological properties

中文摘要:

      采用甲苯-2,4-二异氰酸酯(TDI)对碳纳米管(CNT)进行表面修饰,制得TDI功能化CNT(CNT-TDI),将其分散于4,4′-二苯基甲烷二异氰酸酯中,通过原位聚合法制备CNT-TDI/热塑性聚氨酯弹性体(TPU)复合材料。利用FTIR、XPS和TG等测试手段,表征和分析了CNT-TDI的表面结构；利用旋转流变仪研究了CNT-TDI含量对CNT-TDI/TPU复合材料动态流变性能的影响。结果表明,TDI成功接枝改性CNT,接枝率约17%。动态流变研究结果表明,随CNT-TDI含量增加,复合材料的储能模量(G′)、损耗模量(G″)和复数黏度(η*)均明显提高,G′和G″交点对应的频率向低频移动,损耗峰频率也向低频偏移,说明复合材料的结构性增强,大分子链松弛时间延长；Han曲线上移且逐渐靠近对角线,van Gurp-Palmen曲线下移,说明复合材料的弹性响应逐渐增强；Cole-Cole曲线拖尾现象消失,说明填料的加入降低了TPU基体的微相分离程度。

英文摘要:

      The functionalized carbon nanotubes (CNT) were prepared by grafting toluene-2,4-diisocyanate (TDI) onto the surface of CNT. Then a series of TDI functionalized carbon nanotubes (CNT-TDI)/thermoplastic polyurethane elastomer (TPU) composites containing various weight percents of CNT-TDI were prepared by prepolymer method via in-situ polymerization. The structure of CNT-TDI was characterized by Fourier-transformed infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TG); and the influences of the dosage of CNT-TDI on the rheological properties of CNT-TDI/TPU composites were studied by a rotational rheometer. The results demonstrate that, TDI successfully grafts onto CNT via the reaction between the groups of -NCO and -COOH, and its content is about 17%. The dynamic rheological studies show that the storage modulus (G′), loss modulus (G″) and the complex viscosity (η*) of pristine TPU increase significantly with the incorporation of CNT-TDI loading. The crossover of G′ and G″ and the tanδ move to low frequency with CNT-TDI contents increasing, which indicates the existence of a network structure in CNT-TDI/TPU composites. Han plots shift upward and gradually close to the diagonal line, and the van Gurp-Palmen plots shift downward, which implies that the elastic response exhibits an increasing trend. Cole-Cole curves show that the phase separation of composites decrease due to the presence of CNT-TDI.