本文選題：熱塑性聚氨酯 + 碳納米管��； 參考：《鄭州大學》2017年碩士論文

【摘要】：導電高分子復合材料(Conductive polymer composites,CPCs)是將一種或多種導電填料加入高分子基體中復合制備而成的一類具有導電功能的復合材料。由于其具有成本低,易加工和性能易調(diào)控等優(yōu)點,受到人們的廣泛關注。CPCs在受到外界刺激(如應變、溫度、有機氣體等)時電阻會發(fā)生規(guī)律的變化,因此其在柔性傳感器領域具有極其廣闊的應用前景。傳統(tǒng)方法制備的CPCs基應變傳感器存在輸出信號不穩(wěn)定,應變范圍小等缺點,限制了其實際應用。隨著研究的深入,人們已制備出了具有較大應變測試范圍的CPCs多孔材料,但是該類材料的力學性能較弱,且應變響應行為的穩(wěn)定性和可回復性較差。因此,通過對多孔材料微觀結構的調(diào)控,制備出具有較大壓縮應變、較高的力學性能、良好的穩(wěn)定性和可回復性的多孔CPCs材料具有重要的研究意義。本文以熱塑性聚氨酯(TPU)為基體,以碳納米管(CNTs)為導電填料,采用單向冷凍與冷凍干燥相結合的方法,制備出質(zhì)輕的柔性CNTs/TPU取向多孔材料。對該材料的結構與性能進行了研究,主要成果如下:1.首次采用單向冷凍-冷凍干燥技術成功制備了具有取向泡孔結構的CNTs/TPU導電復合材料�？讖郊s為10μm,CNTs均勻的分布在TPU基體中。由于CNTs分散均勻以及CNTs和TPU之間結合良好,CNTs/TPU取向多孔材料具有超低逾滲值(體積分數(shù)為0.0023%)。由于多孔結構的存在,取向多孔材料的密度低至0.13 g·cm-3。與無規(guī)多孔CPCs材料相比,其在取向方向上的力學性能得到了顯著的提高。2.研究了CNTs/TPU取向多孔材料的壓敏特性。在壓縮過程中復合材料的電阻值隨壓縮應變的增大呈現(xiàn)出單調(diào)下降的趨勢,在回復過程中電阻上升并且能夠較好的回復到初始值。這是由于壓縮過程中泡孔壁相互接觸形成更多的導電通路,使得材料的電阻值下降;而在回復過程中因受壓而接觸的泡孔壁又再次分離,導致導電通路的減少而使電阻值上升。復合材料在壓縮應變下在較大的壓縮應變范圍(0-77%)內(nèi)顯示出良好的線性行為。基于構筑的取向多孔結構,該材料具有良好的結構完整性和優(yōu)異的力學性能,在2000個循環(huán)壓縮之后依然保持著良好的穩(wěn)定性和可回復性,表明該材料具有良好的耐久性,適合長期使用。另外,材料在多種不同的人體運動下模式下均顯示出較快的響應速率以及良好的穩(wěn)定性,顯示了其在人體運動檢測領域的潛在應用價值。3.研究了CNTs/TPU取向多孔材料的彎曲敏感性能以及拉伸敏感性能。在彎曲過程中材料的電阻值呈現(xiàn)出單調(diào)下降的趨勢,回復過程電阻上升,與壓縮過程不同的是,其電阻不能回復到初始值,這是由于彎曲過程中部分導電網(wǎng)絡受到了永久性破壞,導致材料的阻值上升。多循環(huán)測試也顯示出較差的穩(wěn)定性。考察了預處理對材料彎曲敏感性能穩(wěn)定性的影響,結果表明對復合材料進行20個循環(huán)的預處理后直接進行循環(huán)彎曲測試,其對穩(wěn)定性提升作用不明顯;而在彎曲處理后給予試樣24 h的回復時間,發(fā)現(xiàn)當預處理應變大于循環(huán)彎曲的應變時復合材料具有良好的穩(wěn)定性和可回復性。另外,在拉伸應變測試時發(fā)現(xiàn)CNTs/TPU取向多孔材料的斷裂伸長率高達170%,遠遠超越了文獻報道的大多數(shù)多孔材料。在拉伸的過程中復合材料的電阻上升,回復時電阻下降。由于部分泡孔壁的永久性破壞導致電阻不能回復到初始值。循環(huán)拉伸結果顯示出較差的穩(wěn)定性。基于彎曲敏感測試預處理的實驗基礎,對復合材料進行20個循環(huán)的預拉伸處理后恢復24 h,材料的拉伸敏感性能的穩(wěn)定性和可回復性性能得到了顯著的提高。
[Abstract]:Conductive polymer composites (CPCs) is a kind of composite material with conductive function prepared by adding one or more conductive fillers into the polymer matrix. Because of its advantages of low cost, easy processing and easy to control performance, the.CPCs is stimulated by the outside world. Such as strain, temperature, organic gas and so on, the resistance will change regularly, so it has an extremely broad application prospect in the field of flexible sensor. The CPCs based strain sensor prepared by traditional methods has the disadvantages of unstable output signal and small strain range, which limits its practical application. With the further research, people have prepared it. CPCs porous materials with large strain testing range, but the mechanical properties of these materials are weak, and the stability and recoverability of the strain response are poor. Therefore, through the regulation of the microstructure of the porous materials, the porous CPCs has large compressive strain, high mechanical properties, good stability and recoverability. The material has important research significance. In this paper, the flexible CNTs/TPU oriented porous materials with light quality were prepared by the method of Unidirectional Freezing and freeze drying, using thermoplastic polyurethane (TPU) as the matrix and carbon nanotube (CNTs) as the conductive filler. The structure and properties of the material were studied. The main achievements are as follows: 1. the first use of single. A CNTs/TPU conductive composite with an orientated bubble structure was prepared successfully by cryo freeze drying. The pore size of the composite was about 10 u m and CNTs was evenly distributed in the TPU matrix. Because of the uniform dispersion of CNTs and the good bonding between CNTs and TPU, the CNTs/TPU oriented porous material has a ultra low percolation value (volume fraction of 0.0023%). The porous structure is due to the porous structure. When the density of the porous material is as low as 0.13 G. Cm-3., compared with the random porous CPCs material, the mechanical properties in the orientation direction are greatly improved by.2., and the pressure sensitivity of the CNTs/TPU oriented porous material is studied. The resistance value of the composite material decreases with the increase of compressive strain during the compression process. In the process of recovery, the resistance rises and can recover to the initial value. This is due to the interaction of the bubble hole wall in the compression process to form more conductive path and the decrease of the resistance value of the material; and the wall of the bubble hole contacted by pressure in the recovery process is again separated, and the conductivity of the conductive path is reduced and the resistance value is increased. The material shows good linear behavior under the larger compression strain range (0-77%) under the compression strain. Based on the constructed orientation porous structure, the material has good structural integrity and excellent mechanical properties. After 2000 cyclic compression, the material still maintains good stability and recoverability, indicating that the material is good. The durability is suitable for long term use. In addition, the material shows a fast response rate and good stability under various human motion patterns. The potential application value of the material in the field of human motion detection.3. has been studied for flexural sensitivity and tensile sensitivity of CNTs/TPU oriented porous materials. The resistance of materials in the process shows a monotonous decline trend and the resistance of the recovery process rises. Unlike the compression process, the resistance can not revert to the initial value. This is due to the permanent damage of the conductive network in the process of bending, which leads to the increase of the material resistance. The multi cycle test also shows the poor stability. Inspection also shows the poor stability. The effect of pretreatment on the stability of the material's flexural sensitivity shows that the composite material is subjected to 20 cycles of pretreatment to test the cyclic bending directly after 20 cycles, and the effect on the stability is not obvious. The recovery time of the 24 h is given after the bending treatment, and it is found that the composite material is more than the strain of the pre treated strain when the strain is larger than the cyclic strain. The material has good stability and recoverability. In addition, the elongation at break of the CNTs/TPU oriented porous material was found to be up to 170% at the tensile strain test. It was far beyond most of the porous material reported in the literature. The resistance of the composite material increased and the electrical resistance decreased during the stretching process. The permanent damage to the wall of some bubbles was destroyed. The resistance can not be recovered to the initial value. The cyclic tensile results show a poor stability. Based on the experimental basis of the flexural sensitivity test preconditioning, the composite material is pretreated with 20 cycles to recover 24 h, and the stability and recoverability of the tensile sensitivity of the material have been greatly improved.
【學位授予單位】：鄭州大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TB332

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