燃料电池用新型聚酰亚胺及聚硫醚砜基质子交换膜的研究

发布时间：2018-01-07 22:32

本文关键词：燃料电池用新型聚酰亚胺及聚硫醚砜基质子交换膜的研究　出处：《上海交通大学》2014年博士论文　论文类型：学位论文

【摘要】：近年来,为了克服Nafion膜成本高、加工困难、高燃料透过率以及工作温度较低(90 oC)的缺点,碳氢聚合物质子交换膜受到了极大的关注和深入研究。其中,磺化碳氢聚合物膜主要应用于中低温(110oC)质子交换膜燃料电池,而酸掺杂碳氢聚合物膜则主要应用于高温(150-200oC)质子交换膜燃料电池。尽管两种膜的研究都取得了较大进展,但性能尚不能完全满足燃料电池汽车的实际使用要求。在磺化碳氢聚合物膜方面,目前存在的主要问题有:1)尽管通过提高离子交换容量(IEC)的方法可以提高质子交换膜的电导率,但往往会导致膜显著溶胀,甚至溶解,从而降低燃料电池的使用寿命;2)在低相对湿度下,膜的质子导电率往往很低(10-2 S/cm),不能满足实际使用要求;3)膜的化学稳定性特别是抗自由基氧化稳定性普遍较差。在酸掺杂聚合物膜方面,尽管随着酸掺杂量的提高,质子交换膜的电导率也逐渐增大,但这往往会导致膜力学强度的明显下降,从而降低工作寿命。此外,这类膜还存在着酸渗漏的问题,随着酸的流失,膜的质子电导率逐渐降低。基于以上存在的问题,本论文设计并制备了一系列新型质子交换膜材料,并深入研究了聚合物的化学结构以及形态结构与性能之间的关系,以求得到综合性能良好的质子交换膜,为未来这一领域的研究提供新的思路。一、利用新型二酐单体联苯-4,4’-二基(二氧代)-4,4’-双(1,8-萘二甲酸酐)(bpnda)与含咪唑基二胺2-(4-氨基苯基)-5-氨基苯并咪唑(apabi)以及1,3-双(4-氨基苯氧基)苯(bapbz)进行共聚反应,制备了一系列咪唑基含量不同的高分子量聚酰亚胺(pis)。在50oc,24h的优化条件下,用浓硫酸进行后磺化处理,成功得到一系列不同磺化度(iec)的含咪唑基磺化聚酰亚胺(spis)。将磺化聚酰亚胺薄膜(质子状态)浸泡在180oc的多聚磷酸介质中14h,进一步形成共价交联。与未共价交联膜(仅磺酸基与咪唑基之间离子交联)相比,这类离子交联与共价交联并存的质子交换膜,不仅具有较低的吸水率和较高的尺寸稳定性,抗自由基氧化性也大大提高。芬顿测试(80°c,3%h2o2+3ppmfeso4)的结果表明,尽管共价交联膜cspi-1/1(注:由bapbz与apabi的摩尔比为1:1所制得的聚合物)与未共价交联膜spi-1/2具有相近的iec,但前者的抗自由基氧化性显著优于后者(前者在芬顿试剂中开始溶解的时间是后者3倍)。此外,在去离子水中,这类离子交联和共价交联并存的磺化聚酰亚胺质子交换膜质子电导率可达0.07-0.30s/cm,表现出良好的综合性能。二、以4,4’-二(4-氨基苯氧基)联苯3,3’-二磺酸(bapbds)、1,4,5,8-萘四甲酸二酐(ntda)以及1,12-二氨基十二烷(dda)三种原料,通过聚合方式的改变,合成了无规共聚物、嵌段共聚物以及序列共聚物三种不同类型的磺化聚酰亚胺。长脂肪链段引入导致的结晶性能,使得嵌段共聚物以及序列共聚物膜在溶胀率上表现出明显的各向异性(平面方向远小于厚度方向),这有利于提高燃料电池的使用寿命。对于iec相同的共聚物膜,在测试条件相同时,嵌段共聚物膜的电导率最高,而无规共聚膜则最低。例如,嵌段共聚物膜b-x10y15(x10和y15分别表示疏水嵌段和亲水嵌段的平均长度为10和15,余下类推)、序列共聚物膜s2以及无规共聚物膜r1的理论iec值都为1.94mmol/g,但它们在60°c去离子水中的质子电导率分别为0.136s/cm、0.127s/cm以及0.100s/cm。此外,嵌段聚合物中亲/疏水链段的长度不同也会导致质子交换膜电导率的差异。例如,60°c,去离子水中,b-x5y7.5、b-x10y15以及b-x15y30的电导率分别为0.12s/cm、0.136s/cm以及0.126s/cm。三、以新型六元环二酐4,4’-(9-9-亚芴基)双(4-苯氧基-1,8-萘酐)(fbpna)为a2型单体,以三(4-氨基苯基)胺(tapa)为b3型单体,按摩尔比1:1进行缩聚反应,成功得到了氨基封端的六元环型超支化聚酰亚胺(hbpi)。在此基础上,用4-苯氧基1,8-萘酐(pna)对hbpi进行端基修饰反应,得到hbpi-pna超支化聚合物。在50oc,24h的优化条件下,使用浓硫酸对上述超支化聚合物进行后磺化处理,成功制得一系列磺化度不同的超支化磺化聚酰亚胺(shbpi及shbpi-pna)。shbpi及shbpi-pna在大多数极性溶剂中均可以溶解,如dmso、dmac、dmf以及nmp等。用双酚a型环氧树脂(badge),对上述shbpi及shbpi-pna进行交联制膜处理,成功得到了cshbpi及cshbpi-pna自支撑膜。cshbpi及cshbpi-pna膜具有良好的耐热性、抗自由基氧化性以及电导率。60oc下,去离子水中,cshbpi-pna50%膜(iec=2.21)的电导率可达0.149s/cm,高于nafion112。此外,在低湿度条件下,cshbpi-pna50%膜的电导率明显高于第二章中合成的线性无规共聚物spi-1/1。四、以4,4’-二氯二苯砜、4,4’-二氯二苯砜-3,3’-二磺酸钠和4,4’-二巯基二苯硫醚为单体进行缩聚,制得了磺化度为80%的磺化聚硫醚砜(spssf80)。将spssf80与含氨基聚苯并咪唑(h2n-pbi)进行共混,并使用3-(2,3-环氧丙氧)丙基三甲氧基硅烷(kh-560)与双酚a环氧树脂(badge)两种交联剂,制备了一系列共价交联共混膜。实验结果表明,与纯磺化聚硫醚砜膜spssf80相比,共价交联膜的最大拉伸强度均有所增加,而断裂伸长率则略有下降。由于pbi组分的加入,并辅以共价交联处理,共混膜的抗自由基氧化性有了很大程度的提高。例如,共价交联膜spssf80/h2n-pbi/kh-560=7/1/3在芬顿测试(80°c,3%h2o2+3ppmfeso4)98min后才开始破裂,比纯的磺化聚硫醚砜spssf50长四倍(20min)。此外,共价交联处理还抑制了膜的溶胀并提高了膜的耐水性。由于亲水性二氧化硅网络结构的形成,低湿度条件下,使用kh-560为交联剂的共混膜的电导率要高于使用双酚a型环氧树脂(badge)为交联剂的共混膜。在去离子水中,所有的交联膜均表现出与nafion相当的质子电导率。五、使用新型间位含咪唑基二胺单体双(2-(3-氨基苯基))二苯并咪唑(mbapbi)或2-(4-氨基苯基)-5-氨基苯并咪唑(apabi)与4,4’-二氨基二苯醚(oda)以及bpnda进行共聚反应,合成了一系列高分子量的含咪唑基聚酰亚胺mpibis以及pibis。mpibis以及PIBIs表现出十分优异的耐热性和抗自由基氧化性。在180°C下,多聚磷酸或磷酸溶液中浸泡5 h,可对mPIBIs以及PIBIs进行酸掺杂。结果表明所有的膜均可达到很高的掺杂量(300 wt%),其中PIBIs膜的掺杂量总体高于mPIBIs膜,这很可能是由于PIBIs的溶解性较好。此外,这类膜也具有较高的电导率(均大于0.02 S cm-1),其中多聚磷酸掺杂量最高的PIBI-1/0,其在170°C、0%相对湿度下的质子电导率高达0.26 S cm-1。在磷酸掺杂量为300 wt%时,160°C下,PIBI-1/1膜的弹性模量可达0.1 GPa,高出相似磷酸掺杂量的商业化mPBI一个数量级。使用磷酸掺杂量300 wt%的PIBI-1/1膜,在180°C的H2/空气燃料电池中测试得知,其最大功率密度可达350 mW cm-2,展示出良好的应用前景。
[Abstract]:In recent years, in order to overcome the Nafion film of high cost, difficult processing, high fuel permeability and low working temperature (90 oC) the shortcomings of hydrocarbon polymer proton exchange membrane has been concerned and researched greatly. The sulfonated hydrocarbon polymer film is mainly used in low temperature (110oC) of proton exchange membrane fuel cell, and acid doped polymer film of hydrocarbon is mainly used in high temperature (150-200oC) of proton exchange membrane fuel cell. Although the study of two kinds of film have made great progress, but the performance is still not fully meet the requirements of the actual use of fuel cell vehicles. The sulfonated hydrocarbon polymer membrane, the main problems are: 1) though the exchange to improve the capacity of ion (IEC) method can improve the conductivity of proton exchange membrane, but often leads to significant membrane swelling, even dissolution, thereby reducing fuel battery life; 2) at low relative humidity Next, the proton conductivity of the membrane tends to be low (10-2 S/cm), can not meet the actual requirements; 3) the chemical stability of the membrane especially the oxidative stability is generally poor. In the acid doped polymer film, although with the increase of amount of doping acid, proton exchange membrane electric conductivity gradually increased, but this often leads to decreased membrane mechanical strength, thereby reducing the working life. In addition, this kind of film has acid leakage problems with acid erosion, membrane proton conductivity decreased gradually. Based on the above problems, this paper presents the design and preparation of a series of novel proton exchange membrane material, and deeply study on the relationship between the chemical structure and morphology of the polymer structure and properties, in order to get the good performance of proton exchange membrane, providing new ideas for future research in this field. A new type, using two anhydride monomer biphenyl -4, 4 '- two base (two oxygen generation) -4,4' - bis (two 1,8- naphthalene anhydride) (bpnda) and imidazole containing two amine 2- (4- aminophenyl) -5- amino benzimidazole (Apabi) and 1,3- (double 4- aminophenoxy) benzene (bapbz) by copolymerization of a high molecular weight polyimide in the same series of imidazole were prepared (PIs). In 50oc, the optimization of 24h condition after treatment with concentrated sulfuric acid sulfonation, successfully obtained a series of different degree of sulfonation (IEC) containing imidazole sulfonated polyimide (SPIs). The sulfonated polyimide film (proton state) soaked in more than 180oC poly phosphoric acid medium 14h, further the formation of covalent cross-linking. With non covalent crosslinking membrane (only between sulfonic acid and ionic crosslinking) compared to the proton ionic cross-linking and covalent crosslinking coexist exchange membrane, dimensional stability, not only has low water absorption and high, anti free radical oxidation is also greatly improved Fenton. The test (80 C, 3%h2o2+3ppmfeso4). The results show that although the covalent cross-linking of membrane cspi-1/1 (Note: the molar ratio of bapbz and Apabi for the 1:1 of the polymer) have similar IEC and non covalent crosslinking of spi-1/2 film, but the anti free radical oxidation was significantly better than the latter (former Fenton starts to dissolve in the reagent the time is 3 times the latter). In addition, in deionized water, this kind of sulfonated polyimide proton ionic cross-linking and covalent cross-linking both proton exchange membrane conductivity can reach 0.07-0.30s/cm, show good overall performance. In two, 4,4 '- two (4- aminophenoxy) 3,3' - biphenyl two sulfonic acid (bapbds). Four two 1,4,5,8- naphthalene acid anhydride (ntda) and 1,12- (DDA) two amino twelve alkyl three kinds of raw materials, through the polymerization mode change, random copolymer, block copolymer and copolymer sequences of three different types of long chain fatty sulfonated polyimide. Using crystallization properties caused by the block copolymer and the sequence copolymer film shows obvious anisotropy in the swelling rate (plane direction is far less than the thickness direction), which is conducive to improve the fuel battery life. For the same IEC copolymer film, in the same test conditions, the highest conductivity of block copolymer films however, random copolymer membrane is the lowest. For example, block copolymer membrane b-x10y15 (X10 and Y15 respectively, the average length of hydrophobic block segment and hydrophilic block was 10 and 15, and so of the rest), the theory of S2 and IEC sequence copolymer film random copolymer film R1 value is 1.94mmol/g, but they are in 60 C deionized water proton conductivity were 0.136s/cm, 0.127s/cm and 0.100s/cm. in addition, block copolymers in hydrophilic / hydrophobic segments of different lengths can lead to differences in proton exchange membrane conductivity. For example, 60 degrees C, deionized water, B-x5y7.5, b-x10y15 and b-x15y30 conductivity respectively 0.12s/cm, 0.136s/cm and 0.126s/cm. three, a new six membered ring two '- 4,4 anhydride (9-9- sub fluorene (4-) - phenoxy -1,8- naphthalene anhydride) (fbpna) A2 type monomer, with three (4- aminophenyl) amine (tapa) was B3 type monomer molar of 1:1 polycondensation reaction, we successfully obtained six membered ring amino terminated hyperbranched polyimide (HBPI). On this basis, 4- phenoxy 1,8- (PNA) of naphthalene anhydride modified reaction to HBPI, hbpi-pna hyperbranched polymers. In 50oc, the optimization conditions of 24h next, the hyperbranched polymer were sulfonated with concentrated sulfuric acid, successfully prepared a series of different sulfonated hyperbranched sulfonated polyimides (shbpi and shbpi-pna) of.Shbpi and shbpi-pna can be dissolved in most polar solvents such as DMSO, DMAC, DMF and NMP. With bisphenol A epoxy resin (badge), Crosslinked membrane treatment on the shbpi and shbpi-pna, cshbpi and cshbpi-pna successfully obtained self support membrane.Cshbpi and cshbpi-pna membrane has good heat resistance, anti free radical oxidation and conductivity of.60oc, deionized water, cshbpi-pna50% (iec=2.21) membrane conductance rate of 0.149s/cm is higher than nafion112., in addition, in low humidity conditions the electrical conductivity of cshbpi-pna50% film was significantly higher than that of linear synthesis in chapter second copolymer spi-1/1. four, with 4,4 '- two chloro two phenyl sulfone, 4,4' - two chloro two phenyl sulfone sulfonate and two -3,3 '- 4,4' - two two mercapto phenyl sulfide as monomer was prepared by polycondensation, sulfonation sulfonation degrees 80% poly sulfide sulfone (spssf80). The spssf80 and amino containing polybenzimidazole (h2n-pbi) blends, and use 3- (2,3- 3-epoxypropoxy) propyltrimethoxysilane (KH-560) and bisphenol A epoxy resin (badge) two was prepared by crosslinking agent. A series of covalent crosslinking blend membrane. The experimental results show that compared with pure sulfonated poly sulfide sulfone membrane spssf80, which increases the maximum tensile strength of covalent crosslinking membrane, but the elongation decreased slightly. The PBI component added, supplemented by covalent crosslinking treatment, anti free radical oxidation of the blend membrane has been greatly the degree of improvement. For example, covalent crosslinking of membrane spssf80/h2n-pbi/kh-560=7/1/3 in Fenton test (80 C, 3%h2o2+3ppmfeso4) after 98min began to rupture, than pure sulfonated poly sulfide sulfone spssf50 four times (20min). In addition, covalent cross-linking treatments also inhibited the swelling of the membrane and improve the water resistance of the film due to the formation of hydrophilic. Silica network structure, low humidity conditions, the conductivity of blend membrane using KH-560 as crosslinking agent than using bisphenol A epoxy resin (badge) as crosslinking agent. The blend membrane in deionized water, all over Combined membrane showed quite Nafion proton conductivity. Five, using a novel imidazole containing two amine monomer bis (2- (3- aminophenyl) two) benzimidazole (mbapbi) or 2- (4- aminophenyl) -5- amino benzimidazole (Apabi) and 4,4 '- two amino two phenyl ether (ODA) and bpnda by copolymerization of imidazole polyimide mpibis and pibis.mpibis and PIBIs showed the heat resistance and anti free radical oxidation of a series of excellent with high molecular weight was synthesized. Under the temperature of 180 C poly phosphoric acid or phosphoric acid soaking solution for 5 h of acid doping on mPIBIs and PIBIs. Results that can all reach the film doping amount is very high (300 wt%), the doping amount of overall PIBIs film is higher than that of mPIBIs membrane, which is likely to be due to the solubility of PIBIs is better. In addition, it also has a high conductivity film (greater than 0.02 S cm-1), and poly phosphoric acid doping The highest PIBI-1/0 in 170 ~ C, 0% relative humidity of the proton conductivity up to 0.26 S cm-1. in phosphoric acid doping amount is 300 wt%, 160 ~ C, the elastic modulus of PIBI-1/1 film is 0.1 GPa, higher than the commercial mPBI similar phosphate doped one order. PIBI-1/1 film using phosphoric acid the doping amount of 300 wt%, that test H2/ air fuel cell at 180 DEG C, the maximum power density of 350 mW cm-2, shows a good application prospect.

【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM911.4

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