聚酰亚胺基复合泡沫的制备与性能研究

发布时间：2018-02-06 04:39

本文关键词： Ag粒子聚酰亚胺复合泡沫电磁屏蔽热稳定性　出处：《哈尔滨理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：聚酰亚胺(PI)材料是一种具有优异性能的聚合物材料,该种材料由于具有优异的物理机械性能、化学性能以及耐高低温性能,被广泛应用于航空航天领域、微电子领域和通讯等高技术领域。近年来,越来越多的研究者对PI材料进行研究,对其研究方向正朝着高性能化、多功能化和低成本化发展。PI的耐高低温性能和优异的物理机械性能,为通过纳米改性该PI材料提供了重要的性能保证,也因此获得了众多研究者对该领域研究的青睐。本文以PI泡沫材料为基体,选择三种不同特性的粒子(金属Ag纳米粒子、Fe_3O_4磁性粒子及羟基化石墨微片)为掺杂填料,获得了一系列掺杂填料含量不同的PI基复合泡沫。对这三种PI基复合泡沫材料进行了结构表征,分析不同掺杂填料及其掺杂含量对PI基复合泡沫的结构及其性能的影响。测试实验结果表明:本实验采用直接离子交换自金属化法所制备获得的Ag纳米是纳米级的。Ag纳米粒子在PI复合泡沫中存在轻微的团聚现象。XRD分析表明,PI/Ag 泡沫的 XRD 曲线在 2θ 为 38.45°、44.1°、64.55°、77.6°处出现了特征衍射峰,分别对应于银粒子的(111)、(200)、(220)、(311)晶面,证实本实验中所制备的单质Ag是面心立方晶系的,且曲线的衍射峰峰形尖锐,均无杂峰,说明单质Ag的结晶性能良好。热性能分析表明,Ag纳米粒子的引入对PI基复合泡沫的初始热分解温度几乎没有影响。红外测试结果表明Ag纳米粒子的引入并没有破坏PI基泡沫材料的化学结构。SEM测试结果表明随着前体溶液中初始含Ag量w(Ag)逐渐增加,PI/Ag复合泡沫中Ag纳米粒子的空间分布密度明显增大,Ag纳米粒子的尺寸不断减小。通过紫外测试可以知道随着Ag纳米粒子含量的增加,PI/Ag复合泡沫的反射率逐渐增加。并且反射率与Ag纳米粒子含量之间有良好的线性关系,但Ag纳米粒子含量增加到一定量后反射率与Ag纳米粒子含量之间不再呈线性关系,PI/Ag复合泡沫的反射率随Ag纳米粒子含量的增加变化越来越小。当以羟基化石墨微片为填料时,扫描电镜表明所制备的石墨微片直径为微米级且能较好的分散在PI泡沫基体中。将石墨微片掺杂到PI泡沫基体中对石墨微片的结晶几乎没有影响。通过FT-IR分析测试可知,在PI/石墨微片复合泡沫中引入的石墨微片对PI泡沫化学结构基本没有影响。DSC测试结果显示出PI/石墨微片复合泡沫具有比较高的玻璃化转变温度,能够保证在较高温度环境下材料的正常使用。从TGA分析测试可知,PI/石墨微片复合泡沫热稳定性与纯PI泡沫相比有所提高,说明石墨微片在一定程度上能够提高聚合物材料的热稳定性。通过SEM对PI/石墨微片复合泡沫材料的微观泡孔结构及其粒子分散状态进行分析,结果表明石墨微片与PI泡沫基体紧密结合且在PI泡沫中均匀分散。通过力学性能测试可以看出,在PI/石墨微片复合泡沫中引入石墨微片使得泡沫基体轻度变硬,同时柔韧性有所降低。当选择Fe_3O_4磁性粒子为填料时,通过红外光谱分析,纯PI泡沫与不同Fe_3O_4含量的PI/Fe_3O_4复合泡沫材料的化学结构基本相同,Fe_3O_4的加入对PI泡沫基体的结构并没有明显的影响。通过SEM测试得出,随着Fe_3O_4磁性纳米粒子含量的逐渐增加,Fe_3O_4磁性纳米粒子粒径逐渐减小,但当Fe_3O_4纳米粒子在PI基复合泡沫中达到10 wt%时会发生轻微的团聚现象。通过XRD测试可知,不同Fe_3O_4纳米粒子掺杂量的PI/Fe_3O_4复合泡沫的结晶性能良好,而且均没有杂峰。通过TG测试得出,不同Fe_3O_4纳米粒子掺杂量的PI/Fe_3O_4复合泡沫的分解温度与PI泡沫材料的分解温度相差较小,说明Fe_3O_4纳米粒子对PI泡沫基体的热稳定性影响比较小。对PI/Fe_3O_4复合泡沫材料的力学性能测试,得出随着Fe_3O_4磁性粒子含量的增加,压缩强度逐渐增强,泡沫材料抵抗变形的能力增大。综上所述,当Fe_3O_4磁性粒子的添加量达到13 wt%时,能够使PI/Fe_3O_4复合泡沫各性能指标达到最优,最终制得兼具热稳定性,物理机械性及电磁屏蔽性的PI/Fe_3O_4复合泡沫材料。
[Abstract]:Polyimide (PI) material is a polymer material with excellent properties. The material has excellent physical and mechanical properties, chemical properties and high temperature properties, is widely used in the field of aerospace, microelectronics and communications and other high-tech fields. In recent years, more and more researchers to study PI materials. The research direction is towards high performance, multifunction and low cost development of.PI high temperature performance and excellent physical properties, provides important guarantee for the performance of the modified nano PI material, also won many researchers in this research field. This paper takes PI foam favored the matrix materials to choose three different characteristics of the particle (Ag nanoparticles, Fe_3O_4 magnetic particles and hydroxyl graphite microchip) as doping filler, obtained a series of PI doped with different filler content complex Synthetic foam. Of the three kinds of PI composite foams were characterized. The influence analysis of structures with different doping filler and the doping content of PI based composite foam and its performance. The experimental results show that this experiment adopts direct ion-exchange self metallization method for Ag nano preparation is the aggregation of.XRD minor the analysis indicated the presence of nano.Ag nanoparticles in the PI composite foam, PI/Ag foam XRD curve at 2 theta 38.45 degrees, 44.1 degrees, 64.55 degrees, 77.6 degrees at the characteristic diffraction peaks, corresponding to the silver particles (111), (200), (220), (311) crystal in this experiment, confirmed that the prepared Elemental Ag is face centered cubic structure, and the diffraction peaks of the curve are sharp, no miscellaneous peak, indicating the crystallization properties of elemental Ag. Analysis shows that the thermal properties of Ag nanoparticles on the introduction of the initial thermal decomposition temperature of PI composite foam hardly Influence. Infrared test results show that the introduction of nano Ag and.SEM chemical structure damage PI based foam material test results show that with the initial Ag content of W precursor solution (Ag) increased gradually, PI/Ag composite foams of Ag nanoparticles in the spatial distribution of the density increase obviously, Ag particle size decreases. By UV the test can know that with the increase of Ag nanoparticles content, the reflectivity of PI/Ag composite foams increased gradually. And there is a good linear relationship between the reflectance and the content of Ag nanoparticles, but Ag nanoparticles content is not a linear relationship between the amount of reflectivity and reflectivity of Ag nanoparticles content of PI/Ag composite foams with Ag nanoparticles with the increase of the content of change more and smaller. When the hydroxylated graphite sheet as filler, scanning electron microscopy indicated that the prepared graphite sheet and micron diameter Can be better dispersed in the PI matrix. The foam graphite Microflake doped into crystalline PI foam matrix of graphite micro sheet has little effect. Through the FT-IR analysis results, introduced in PI/ graphite MICROFLAKY foam in graphite sheet of PI foam chemical structure does not affect the basic results of.DSC test showed that PI/ graphite micro composite foam having a glass transition temperature is relatively high, can guarantee the normal use of materials in high temperature environment. The analysis test shows from TGA, PI/ graphite MICROFLAKY foam thermal stability was improved compared with that of pure PI foam, graphite sheet to a certain extent, can improve the thermal stability of polymer materials. Through the analysis of the micro pore structure of SEM PI/ graphite Microflake composites and the particle dispersion state, results show that the graphite sheet and PI foam matrix combination and in PI foam Dispersed. Through the test of mechanical property can be seen in the introduction of PI/ graphite graphite MICROFLAKY foam microchip makes the foam matrix mild harden, while the flexibility decreased. When choosing Fe_3O_4 magnetic particles as filler, through infrared spectrum analysis, the chemical structure of PI/Fe_3O_4 composite foam pure PI foam with different content of Fe_3O_4 basic the same, the addition of Fe_3O_4 on the structure of PI foam matrix has no obvious influence. With the SEM test, with the increasing content of Fe_3O_4 nanoparticles, Fe_3O_4 nanoparticles particle size gradually decreases, but when the Fe_3O_4 reached 10 wt% nanoparticles in PI based composite foam happens weak aggregation. By XRD test the crystallization properties of PI/Fe_3O_4 composite foams with different Fe_3O_4 nanoparticles doping amount is good, and no impurity peaks. With the TG test, not PI/Fe_3O_4 composite foam with Fe_3O_4 nanoparticles doped with PI decomposition temperature of the foam decomposition temperature difference is small, it shows that the thermal stability effect of Fe_3O_4 nanoparticles on PI foam matrix is relatively small. Test the mechanical properties of PI/Fe_3O_4 composite foam material, with the increase of Fe_3O_4 magnetic particle content, the compressive strength gradually increased, the foam resistance the ability of deformation increases. To sum up, when the adding amount of Fe_3O_4 magnetic particles reached 13 wt%, can make PI/Fe_3O_4 composite foam the performance index of optimal, finally prepared with thermal stability, PI/Fe_3O_4 composite foam material physical mechanical and electromagnetic shielding.

【学位授予单位】：哈尔滨理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ328;TB33

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