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生物基邻苯二甲腈树脂碳材料的制备及应用研究

Preparation and Application Research of Carbon Materials with Bio-based Phthalonitrile Resin as Precursor

【作者】 周涛

【导师】 杨刚;

【作者基本信息】 四川大学 , 高分子科学与工程, 2021, 硕士

【摘要】 近年来,为了应对能源危机问题,生物质来源的葡萄糖、蛋白质、DNA等结构片段被研究者们以化学手段引入到高分子材料中,成功替换了原来的石油基结构,不仅实现了性能上的突破,而且为高分子材料可持续发展的理念奠定了基础。邻苯二甲腈(PN)树脂是一种经典的高性能热固性树脂,具有非常好的热氧稳定性、机械性能和耐化学腐蚀性的,其在航空航天、船舶、封装等领域有着重要的应用价值。随着生物基材料的兴起,学者们对生物基PN树脂也开展了大量研究。与传统的PN树脂相比,生物基PN树脂除了具有高残碳、高热稳定性等优点以外,还具有能够自催化固化、氮含量高、氢键丰富等优点。随着越来越多含有生物基的PN单体被合成出来,拓展生物基PN树脂的应用也成为了学者们更加关注的课题。多孔碳材料以其价廉、质轻、孔径结构丰富、比表面积大而被广泛用作电磁屏蔽材料、吸附材料、电极材料等。多孔碳材料的结构特征主要是由前驱体结构和加工方法决定的,前驱体分类主要包括小分子、高分子、生物质等。然而,直接取自于自然界的生物质难以进行化学结构的精确控制,导致其重复率低,而且材料的热稳定性较差,大多数情况下产率相对较低。而生物基邻苯二甲腈单体不仅具有丰富的分子结构设计灵活性,而且氰基的存在能够极大的提高材料的热稳定性和含氮量。因此,生物基邻苯二甲腈树脂在碳材料领域具有很大的发展潜力,但是文献对于生物基邻苯二甲腈树脂碳材料的应用研究不多。本文对生物基PN树脂的碳化裂解行为、前驱体结构调控以及结构与性能的关系做了系统研究,拓展了生物基PN树脂在电磁屏蔽和电化学领域的应用。本文主要的工作内容如下:首先,通过使用热重-红外-质谱(TG-FTIR-MS)联用和热裂解-气相色谱/质谱(PY-GC/MS)联用两种表征手段探讨了酪氨酸基邻苯二甲腈树脂(TPN)的热降解机理。TG-DTG结果表明,酪氨酸邻苯二甲腈树脂的热降解过程可以分成三个阶段。TG-FTIR-MS结果表明,第一个阶段主要释放的气体是CO2、CO、CH4等,主要与酪胺结构单元的热裂解有关。第二个阶段观察到了大量的NH3、HCN等气体释放,主要与TPN树脂的三嗪环、异吲哚啉结构中的碳氮键断裂有关。第三阶段大量H2的产生是由于稠环的融合和碳化反应导致的C-H键断裂。PY-GC/MS分析了TPN树脂在900 oC快速裂解释放的小分子如苯酚、对甲酚、邻苯二甲腈、苯乙腈等。根据结果我们判断了断键方式,推测出了生物基TPN树脂的高温热解机理。其次,在不同温度下碳化制备了以腺嘌呤邻苯二甲腈(ADCN)树脂作为前驱体的多孔碳材料。通过SEM碳材料的形貌结构进行表征,表明ADCN碳材料内部具有丰富的孔结构。并且表现出了优异的电导率,有利于对电磁波的损耗。对碳化后的样品进行了弯曲性能和压缩性能的测试,材料表现出了相比一般碳材料高很多的力学性能。密度和收缩率的测试表明石墨烯与ADCN的复合能够有效减小碳化收缩率。电磁屏蔽性能测试表明在800-1000oC的碳化温度范围内,碳材料具有高达35-40 d B的优异的电磁屏蔽性能。与7.5wt.%石墨烯复合时,材料的EMI性能提升了10 d B。最后,以腺嘌呤邻苯二甲腈(ADCN)分子作为前驱体,通过活化法一步聚合-碳化工艺制备了可用作超级电容器的电极材料。并且对比了不同的盐类活化剂活化碳化ADCN的效果,获得了具有较高比电容的可用于超级电容器的碳电极材料,表明ADCN是一种优异的碳材料前驱体。以不同结构的邻苯二甲腈分子作为前驱体,以Mg Cl2·6H2O作为盐模板的制孔方法制备了多孔碳电极材料,通过SEM、XRD、拉曼、BET等测试对比了ADCN和APCN结构对所得碳材料电化学性能的影响。

【Abstract】 In recent years,in order to deal with the crisis of energy,many kinds of fragments from biomass such as glucose、protein and DNA were introduced into polymer materials by chemical means,replaceing the former petroleum based structure.It not only achieved a breakthrough in performance,but also laid the foundation for the sustainable development of polymer materials.Phthalonitrile(PN)resin is a kind of classic high-performance thermosetting resin,which has excellent thermal oxygen stability,mechanical properties and chemical corrosion resistance.It has important application prospects in aerospace,shipping,packaging and so on.With the rise of bio-based materials,scholars have carried out a lot of research on bio-based PN resin.Compared with traditional PN resin,bio-based PN resin not only has the advantages of high residual carbon and high thermal stability,but also has the advantages of autocatalytic curing,high nitrogen content and rich hydrogen bonds.As more and more bio-based PN monomers are synthesized,how to expand the application of bio based PN resin has become a more concerned problem.Porous carbon materials are widely used as electromagnetic shielding materials,adsorption materials and electrode materials on account of their low price,light weight,rich pore structure and large specific surface area.The properties of porous carbon materials are determined by the structure of precursors and processing method.The precursors of porous carbon materials are mainly classified as small molecules,polymers,biomass and so on.However,it is difficult to control the chemical structure of biomass directly from nature,resulting in low repetition rate,and their poor thermal stability is also a disadvantage.Bio-based phthalonitrile monomer not only has rich flexibility in molecular structure design,but also can greatly improve the carbon yield and nitrogen content of materials attributed to the cyano groups.Therefore,bio-based phthalonitrile resin has great development potential in the field of carbon materials,but there is little research on the application of bio-based phthalonitrile resin carbon materials in the literature.In this paper,the decomposition behavior,precursor structure control and the relationship between structure and properties of bio-based PN resin were syste-matically studied,which expanded the application of bio-based PN resin in the field of electromagnetic shielding and electrochemistry.The main work of this paper is as follows:Firstly,the thermal degradation mechanism of tyrosine based phthalonitrile resin(TPN)was investigated by tg-ftir-ms and Py-GC/MS.TG-DTG results showed that the thermal degradation of tyrosine phthalonitrile included three stages.The results of TG-FTIR-MS show that the main gases released in the first stage are CO2,CO and CH4,which are mainly related to the fracture of tyramine structural units.In the second stage,a large amount of gases such as NH3and HCN were observed,which were mainly related to the C-N bond breaking in the triazine ring and isoindoline structure of TPN resin.In the third stage,a large amount of H2was produced due to the fusion of fused rings and the fracture of C-H bond.Py-GC/MS results showed that small molecules such as phenol,p-cresol,phthalonitrile and phenylacetonitrile were released from TPN resin at 900 oC.According to the results,we judged the mode of bond breaking and speculated the high temperature pyrolysis mechanism of bio based TPN.Secondly,the porous carbon materials from ADCN resin were prepared by carbonization at different temperatures.The morphology of the carbon materials were characterized by SEM.The results show that there are abundant pore structures in the ADCN carbon materials.The results of bending and compression tests show that the addition of graphene can effectively improve the mechanical properties of carbon materials.The density and shrinkage tests also show that the presence of graphene can reduce the carbonization shrinkage.The electromagnetic shielding performance test shows that in the carbonization temperature range of 800-1000oC,the electromagnetic shielding performance of carbon materials is in the range of 35-40d B,which has excellent electromagnetic shielding performance.When 7.5wt.%graphene is added,the EMI performance of the material is improved by 10d B.Finally,adenine-based phthalonitrile(ADCN)was used as the precursor to prepare electrode materials for supercapacitors by one-step activation polymerization carbonization process.The results show that ADCN is an excellent precursor for carbon materials.The porous carbon electrode materials were prepared by comparing different structures of phthalonitrile molecules as precursors and Mg Cl2·6H2O as the salt template.The effects of ADCN and APCN structures on the electrochemical properties of the carbon electrode materials were investigated by SEM,XRD,Raman and BET.

  • 【网络出版投稿人】 四川大学
  • 【网络出版年期】2025年 02期
  • 【分类号】TQ127.11;TQ320.1
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