新型含硫聚苯并咪唑质子交换膜的制备与性能研究
发布时间：2018-08-08 12:00
【摘要】：质子交换膜作为质子交换膜燃料电池的核心部件,其抗氧化稳定性一直是制约其使用寿命的关键因素之一,尤其是聚苯并咪唑类的质子交换膜材料,由于其具有活性反应位点,较易受到来自燃料电池工作过程中所产生氧化自由基的进攻而降解。另一方面,硫醚结构在抗氧化方面有着潜在的广阔应用,一直以来,在药学、生物学、有机化学等领域的研究有很多报道,但是在聚合物材料方面,尤其是聚苯并咪唑结构中的抗氧化应用罕见报道。因此,研究硫醚添加剂作为聚苯并咪唑系列聚合物中的有效抗氧化措施,具有重要的意义。本文合成了三种具有不同结构特点的硫醚添加剂,以一定的比例将其引入了己二酸／吡啶二酸与联苯四胺的共聚体系,得到了不同比例的各具结构特征的含硫聚苯并咪唑聚合物,并进行了成膜和后续性能研究,包括基本结构表征、机械性能测试、热稳定性测试、掺酸及溶胀测试、质子传导率测试,以及高浓度的Fenton测试等。具体研究成果如下：(1)合成了结构中具有刚性芳香硫醚结构的新型单体3,3'-[(硫代二(4,1-亚苯基))二硫]二丙酸二甲酯(DTMA),将其引入己二酸／吡啶二酸与联苯四胺的共聚体系,并制备得到一系列共聚膜。测试结果表明芳香硫醚结构的引入使膜的抗氧化性有了显著提高,其中含硫比例最高的PBI-DTMA-5%在高浓度Fenton试剂浸泡24 h后失重不到3%,远优于文献值。本研究由此提出了可能的硫醚抗氧化过程猜想,并通过红外分析、拉伸测试、热重测试进行了讨论。进一步的研究表明,在高浓度的Fenton试剂处理后,含硫膜保持了相当程度的力学与热稳定性。(2)为进一步研究引入硫醚结构对聚苯并咪唑的综合影响,本文特定地合成了与己二酸结构相似的3-[(2-甲氧基-2-氧代乙基)硫代]丙酸甲酯(MTMA),按一定比例替换己二酸进行与吡啶二酸、联苯四胺的共聚反应,得到系列聚合物并制备成膜。在160℃时,PBI-MTMA-7%膜的质子传导率已经达到29.25 mS·cm-1。此外,聚合物溶解性测试结果还表明,脂肪硫醚结构的存在极大促进了聚苯并咪唑结构的溶解,对于加工性能一直存在缺陷的聚苯并咪唑类材料而言是一个非常明显的性能改善。(3)在之前的硫醚研究工作基础上,本文合成了具有立体结构的硫醚单体10-乙基-10H-吩噻嗪-3,7-二醛(PTZA),将其引入聚苯并咪唑主链并制备成膜。测试表明含立体硫醚结构的聚苯并咪唑不只溶解性能更佳,相应的膜在热稳定性、掺酸量及质子传导率等方面均比无硫醚添加的膜有明显优势。在160℃时,PBI-PTZA-5%膜的质子传导率已经达到38.63 mS·cm-1,骨架分解温度大于450℃,综合性能优异。本文提出的以硫醚添加剂作为聚苯并咪唑抗氧化措施的方法简便易行,原料廉价易得,测试性能优异。通过共聚的途径引入,不容易出现相分离等现象,具有普适性。本文的研究工作为聚苯并咪唑系列聚合物的抗氧化提供了新的思路。
[Abstract]:As the core component of proton exchange membrane fuel cell, the antioxidant stability of proton exchange membrane is one of the key factors that restrict its service life, especially the proton exchange membrane material of polybenzimidazole, because of its active reaction site. It is easy to be degraded by the attack of oxidized free radicals produced during the operation of the fuel cell. On the other hand, the structure of thioether has a potential wide application in antioxidation. It has been reported in many fields such as pharmacy, biology, organic chemistry and so on, but in the field of polymer materials, Especially in the structure of polybenzimidazole, the application of antioxidation is rare. Therefore, it is of great significance to study sulfide additive as an effective antioxidation measure in polybenzimidazole series polymers. In this paper, three kinds of thioether additives with different structure were synthesized and introduced into the copolymerization system of adipic acid / pyridylic acid and biphenyl tetraamine at a certain proportion. Different proportions of sulfur containing polybenzimidazole polymers were obtained, and film formation and subsequent properties were studied, including basic structure characterization, mechanical properties test, thermal stability test, acid doping and swelling test. Proton conductivity test and high concentration Fenton test. The specific research results are as follows: (1) A new monomer 3C3O- [(thiobis (4- (4- (4-) -phenylene)] dithio-dimethyl propionate (DTMA),) with rigid aromatic sulfide structure has been synthesized and introduced into the copolymerization system of adipic acid / pyridinic acid and biphenyl tetraamine. A series of copolymer membranes were prepared. The results showed that the antioxidation of the membrane was improved by the introduction of aromatic thioether structure. The PBI-DTMA-5%, which had the highest sulfur content, lost less than 3% weight after immersion in high concentration Fenton reagent for 24 h, which was much better than the reference value. In this study, the possible antioxidation process of sulfide was suggested and discussed by infrared analysis, tensile test and thermogravimetric test. Further studies showed that the sulfur-containing membrane maintained a considerable degree of mechanical and thermal stability after treatment with high concentration of Fenton reagent. (2) for further study, the influence of the structure of sulfide on polybenzimidazole was studied. In this paper, 3- [(2-methoxy-2-oxyethyl) thiothioyl] propionate (MTMA), which is similar to adipic acid in structure, was specially synthesized by replacing adipic acid with pyridinedioic acid and biphenytetracylamine in a certain proportion, and a series of polymers were obtained and the films were prepared. The proton conductivity of PBI-MTMA-7% membrane has reached 29.25 mScm-1 at 160 鈩，
本文编号：2171725
[Abstract]:As the core component of proton exchange membrane fuel cell, the antioxidant stability of proton exchange membrane is one of the key factors that restrict its service life, especially the proton exchange membrane material of polybenzimidazole, because of its active reaction site. It is easy to be degraded by the attack of oxidized free radicals produced during the operation of the fuel cell. On the other hand, the structure of thioether has a potential wide application in antioxidation. It has been reported in many fields such as pharmacy, biology, organic chemistry and so on, but in the field of polymer materials, Especially in the structure of polybenzimidazole, the application of antioxidation is rare. Therefore, it is of great significance to study sulfide additive as an effective antioxidation measure in polybenzimidazole series polymers. In this paper, three kinds of thioether additives with different structure were synthesized and introduced into the copolymerization system of adipic acid / pyridylic acid and biphenyl tetraamine at a certain proportion. Different proportions of sulfur containing polybenzimidazole polymers were obtained, and film formation and subsequent properties were studied, including basic structure characterization, mechanical properties test, thermal stability test, acid doping and swelling test. Proton conductivity test and high concentration Fenton test. The specific research results are as follows: (1) A new monomer 3C3O- [(thiobis (4- (4- (4-) -phenylene)] dithio-dimethyl propionate (DTMA),) with rigid aromatic sulfide structure has been synthesized and introduced into the copolymerization system of adipic acid / pyridinic acid and biphenyl tetraamine. A series of copolymer membranes were prepared. The results showed that the antioxidation of the membrane was improved by the introduction of aromatic thioether structure. The PBI-DTMA-5%, which had the highest sulfur content, lost less than 3% weight after immersion in high concentration Fenton reagent for 24 h, which was much better than the reference value. In this study, the possible antioxidation process of sulfide was suggested and discussed by infrared analysis, tensile test and thermogravimetric test. Further studies showed that the sulfur-containing membrane maintained a considerable degree of mechanical and thermal stability after treatment with high concentration of Fenton reagent. (2) for further study, the influence of the structure of sulfide on polybenzimidazole was studied. In this paper, 3- [(2-methoxy-2-oxyethyl) thiothioyl] propionate (MTMA), which is similar to adipic acid in structure, was specially synthesized by replacing adipic acid with pyridinedioic acid and biphenytetracylamine in a certain proportion, and a series of polymers were obtained and the films were prepared. The proton conductivity of PBI-MTMA-7% membrane has reached 29.25 mScm-1 at 160 鈩，
本文编号：2171725
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