微胶囊及碳纤维改性对不饱和聚酯自修复复合材料的性能影响研究

发布时间：2018-05-20 06:18

本文选题：自修复 + 微胶囊　；参考：《陕西科技大学》2017年硕士论文

【摘要】：不饱和聚酯(UP)复合材料因其优异的力学性能、良好的耐热性和抗疲劳性等特点,广泛应用于航天航空、电子和建筑等领域,但该材料在长期使用过程中会产生微裂纹,若微裂纹没有及时修复,将导致材料的力学性能和尺寸稳定性下降,进而影响材料的使用性能。微胶囊型功能性材料不仅可以提高复合材料的韧性,还可以通过对微裂纹的自动响应实现对微裂纹的自修复,使其在新材料研究领域备受青睐。然而由于微胶囊配方体系的不同,合成工艺的差异,导致其微观结构差异较大,且与基材的界面结合程度也不同,进而影响复合材料的基本性能。碳纤维(CF)因其比强度高、比模量高、摩擦系数低等优点而经常用作树脂基复合材料的增强体,但其呈化学惰性、表面能低、与树脂基体粘结性差等缺点限制了在复合材料中的发展。因此如何实现复合材料自修复功能长期稳定性的同时,尽量减少因微胶囊和CF的引入而导致的复合材料性能下降是迫切需要解决的问题。本研究采用原位聚合法以三聚氰胺-脲醛树脂为壁材,环氧树脂(E-51)为芯材制备微胶囊(MUF),将其应用于碳纤维增强不饱和聚酯(CF/UP)复合材料中,详细探讨了CF和MUF含量对UP复合材料结构和性能的影响,确定了最佳用量。通过光学显微镜(OM)和扫描电子显微镜(SEM)观察MUF的表面形貌;傅里叶变换红外光谱仪(FTIR)对MUF、CF/UP复合材料和微胶囊/碳纤维/不饱和聚酯(MUF/CF/UP)复合材料的化学结构进行表征;热重分析仪(TGA)、动态力学分析仪(DMA)、悬臂梁冲击仪和万能拉力试验机对复合材料的热学、力学性能及自修复性能进行测试。结果表明,当CF和MUF含量均为1wt%时,MUF/CF/UP复合材料的热学、力学性能及自修复性能较佳,但由于MUF和CF与UP基体的相容性较差,MUF和CF的加入仍对复合材料的性能造成了影响。为改善上述问题,通过表面处理法和化学接枝法分别对CF和MUF进行改性,探讨了改性剂种类、改性工艺、改性方法对CF及MUF表面形貌、化学结构及热性能的影响,研究了不同改性工艺制备的CF及MUF对MUF/CF/UP复合材料热学、力学性能及自修复性能的影响。通过FTIR表征改性前后MUF、CF及复合材料的化学结构;SEM观察改性前后MUF、CF的表面形貌变化及MUF、CF在复合材料中的分散性;X射线光电子能谱仪(XPS)研究MUF及CF与改性剂界面间的相互作用力,揭示改性剂的作用机理;并利用TGA、DMA、冲击试验机、硬度计、万能拉力试验机等研究自修复组分对UP复合材料热学、力学性能及自修复性能的影响。结果表明,H_2O_2与浓HNO_3处理20min后的CF(OCF_和OCF2)及KH-570接枝改性的CF(KCF)表面粗糙度和活性官能团含量均增加,从而改善了CF与UP基体的界面相容性。其中MUF/OCF_/UP复合材料较MUF/OCF2/UP复合材料而言,综合力学性能更好,MUF/KCF/UP复合材料的力学性能最佳,自修复效率较高,可达67.03%。表明CF经过改性后,改善了其与基体的界面相容性,提高了复合材料的性能。KH-151与KH-570于60℃时表面处理的微胶囊(MUF1和MUF2)及KH-570接枝改性的微胶囊(MUF_3)形状规则、表面粗糙,与UP基体结合更加紧密。比较可得,MUF2/OCF_/UP复合材料的综合力学性能比MUF1/OCF_/UP复合材料的好,MUF_3/OCF_/UP自修复复合材料的力学性能最佳,自修复效率较高,可达70.77%。表明MUF的改性可以提高微胶囊与不饱和聚酯基体材料之间的界面结合力。
[Abstract]:Unsaturated polyester (UP) composites are widely used in aerospace, electronic and architectural fields because of their excellent mechanical properties, good heat resistance and fatigue resistance. However, microcracks will occur during the long term use of the materials. If the micro cracks are not repaired in time, the mechanical properties and dimensional stability of the materials will be reduced. The microcapsule type functional material can not only improve the toughness of the composite, but also realize the self repair of micro cracks by the automatic response to the micro crack, which makes it popular in the research field of new materials. However, the difference in the synthetic process of the microcapsule formulation system leads to the microjunction of the microencapsulation. The structure of the carbon fiber (CF) is often used as an enhancer for resin based composites because of its high specific strength, high specific modulus and low friction coefficient, but its chemical inertness, low surface energy and poor adhesion to the resin matrix are limited by the advantages of high specific strength, high modulus and low friction coefficient. The development of composite materials, therefore, how to realize the long-term stability of composite self repair function and minimize the degradation of composite properties caused by the introduction of microcapsules and CF is an urgent problem to be solved. In this study, in situ polymerization, melamine urea formaldehyde resin was used as wall material and epoxy resin (E-51) as core material. Microcapsules (MUF) were prepared and applied to carbon fiber reinforced unsaturated polyester (CF/UP) composites. The effects of CF and MUF content on the structure and properties of UP composites were discussed in detail. The optimum dosage was determined. The surface morphology of MUF was observed by optical microscopy (OM) and scanning electron microscopy (SEM); Fourier transform infrared spectrometer (FTIR) was used to observe the surface morphology of MUF. The chemical structure of MUF, CF/UP composites and microcapsule / carbon fiber / unsaturated polyester (MUF/CF/UP) composites was characterized; thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), cantilever beam impact instrument and universal tension test machine were used to test the thermal, mechanical and self repair properties of the composites. The results showed that when CF and MUF contained the composites, the composite materials were tested. When the quantity is 1wt%, the thermal, mechanical and self repairing properties of MUF/CF/UP composites are better. But because of the poor compatibility of MUF and CF with UP matrix, the addition of MUF and CF still affects the properties of the composites. In order to improve the above problems, the modification of CF and MUF is carried out by surface treatment and chemical grafting method, and the modification is discussed. The effects of agent type, modification process, modification method on the surface morphology, chemical structure and thermal properties of CF and MUF, and the effects of CF and MUF on the thermal, mechanical and self repairing properties of MUF/CF/UP composites prepared by different modification processes. The chemical structure of MUF, CF and composite materials were characterized by FTIR; SEM observed before and after the modification of MUF, C. The surface morphology changes of F and the dispersion of MUF and CF in the composite; X ray photoelectron spectroscopy (XPS) study the interaction force between MUF and the interface of CF and modifier, reveal the mechanism of action of the modifier, and use TGA, DMA, impact testing machine, hardness tester, universal tensile test machine to study the thermal and mechanical properties of the self repairing component to UP composite. The results show that the surface roughness and active functional group content of CF (KCF) and CF (KCF) modified by CF (OCF_ and OCF2) and KH-570 graft modified by H_2O_2 and 20min are all increased, and the interfacial compatibility between CF and UP matrix is improved. It is better that the mechanical properties of MUF/KCF/UP composites are the best and the self repairing efficiency is high, and the 67.03%. shows that after the modification of CF, the interfacial compatibility between the composite and the matrix is improved, and the microcapsules (MUF1 and MUF2) and the microcapsule (MUF_3) shape rule of the KH-570 graft modified by KH-570 at 60 C are improved. The surface of the MUF2/OCF_/UP composite is better than that of the MUF1/OCF_/UP composite. The mechanical properties of the MUF_3/OCF_/UP self repairing composites are the best and the self repairing efficiency is higher. The 70.77%. shows that the modification of MUF can improve the microencapsulation and unsaturated polyester matrix. The bonding force between the interface.
【学位授予单位】：陕西科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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