什么叫聚磷腈高分子,以及它的意义(学术意义或经济意义、叙述该领域目前的情况(国内外),

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/15 06:06:36

什么叫聚磷腈高分子,以及它的意义(学术意义或经济意义、叙述该领域目前的情况(国内外),
什么叫聚磷腈高分子,以及它的意义(学术意义或经济意义、叙述该领域目前的情况(国内外),

什么叫聚磷腈高分子,以及它的意义(学术意义或经济意义、叙述该领域目前的情况(国内外),
【题 名】具有规整PPV侧链无机高分子聚磷腈的合成与表征
【作 者】刘承美 胡富贞 甘志伟 梁万里
【机 构】华中理工大学化学系,武汉430074 香港浸会大学化学系香港九龙塘
【刊 名】化学推进剂与高分子材料, 2004(1): 31-34
【关键词】聚磷腈 合成 寡聚聚对苯乙炔 接枝聚合物 无机非金属材料 无机高分子 蓝色发光
【文 摘】利用反应性无机高分子聚(二氯)磷腈与功能性寡聚聚对苯乙炔的亲核取代反应,合成了具有规整寡聚聚对苯乙炔(OPPV)侧链的高分子聚磷腈(PPZ).采用NMR(^31P,^1H,^13C),FT-TR、GPC、DSC、TGA等对所得无机聚合物进行了结构表征和性能测试.以所合成的聚合物作发光材料,制备了聚合物发光器件,并对器件性能进行了初步研究.实验结果表明:聚合物具有优异的溶解性能和成膜性能,通过旋涂法可获得符合要求的发光薄膜.聚合物玻璃化转变温度(Tg)为97℃,开始热分解温度为387℃.聚合物LED的发光波长为412nm,为蓝色电致发光.
高分子固体电解质(SPE)是一类新型的薄膜材料,在固态电池和其他领域有着极大的应用潜力.聚氧化乙烯(PEO)是最早用于制备高分子固体电解质的高分子材料.在过去的二十年间,这一领域取得了很大的进展,但由于PEO高分子的结晶性使得以其为基材的SPE电导率不佳.因而近年来人们研究并开发了许多无机高分子固体电解质,带有寡聚氧化乙烯侧链的聚磷腈高分子就是其中的典型代表之一.本文利用两种新型的含氟氮超酸锂盐和两种新型聚多氟烷氧基磺酰亚胺锂盐同三种带有寡聚醚链的聚磷腈高分子(聚(寡聚乙氧基)磷腈,MEEP、MEEEP、MEEEEP)通过溶液-熔融法制备SPE,并初步研究了它们的导电性能,电化学稳定性和热稳定性.实验结果表明:实验中制备的SPE的离子导电特性符合无定型高分子固体电解质体系的基本规律.本文制备了一种含支化酯型结构的磺酰亚胺锂盐(二(1,1,1,3,3,3-六氟-2-丙氧基)磺酰亚胺锂,LiHFPSI)同甲氧基醚取代的聚有机磷腈高分子的复合电解质体系MExP-LiHFPSI(其中x=2、3、4).通过改变聚磷腈高分子聚醚侧链的长度,研究了高分子主体结构对SPE导电系能的影响,发现随着寡聚醚侧链长度的增加,室温(25℃)电导率也随之增大,这一结果与非晶态电解质Vogel-Tamann-Fulcher (VTF)方程计算出的活化能结果相吻合.通过与MExP-LiTFSI体系的对比,发现MExP-LiHFPSI体系具有同样良好的离子导电性能,电化学稳定性优于MExP-LiTFSI体系,同时其阴离子的特殊结构还有利于提高体系的阳离子迁移数.随着阴离子中含氟基团数目的增加,SPE的电化学稳定性增加,这一结果与量化计算的锂盐阴离子HOMO轨道能量的变化规律是一致的.热分析(DSC和TGA)测试结果表明MExP-LiHFPSI体系具有较低的玻璃转化温度,在-100~100℃温度范围内没有发现体系的熔点Tm,实验体系在30~200℃无分解.在实验制备的MExP-LiHFPSI体系中,MEEEEP-LiHFPSI(mol Li/rpt unit=0.375)具有最佳的综合性能,室温电导率为4.48×10-4S/cm,电化学窗大于6V,在30~200℃无分解.本文还制备了两种聚合物锂盐同聚磷腈高分子MEEP的复合电解质体系,发现MEEP同聚((4,4’-六氟异亚丙基)二苯氧基)磺酰亚胺锂制备最佳体系(mol Li/rpt unit=0.125)的室温电导率为2.42×10-5S/cm,且具有较好的力学形态和5.5V的电化学窗,热稳定性也较好.研究结果表明,聚磷腈同含氟氮超酸锂盐制备的高分子固体电解质材料具有优良的离子导电性能,极佳的电化学稳定性和热稳定性,在二次锂电池和其他电子器件方面有着极大的应用价值.
Solid polymer electrolytes have emerged as an exciting class of novel electrolyte membrane materials with potential applications in solid-state batteries and other devices. Although poly(ethylene oxide) (PEO) was the first solid polymeric electrolyte discovered, poor ambient ionic conductivity was obtained due to its crystallinity. The limitation of this polymer has prompted a search for alternatives, polyphosphazenes bearing oligoethyleneoxy side groups are typical examples.A new series of lithium superacid salts have been mixed with poly(oligoethylene oxide)phosphazenes by dissolving-melting method to prepare the SPEs and its conductivity, electrochemical stability and thermal stability behaviors of these SPEs have been studied. The results showed that the behavior of these SPEs had typical characterizations of the amorphous SPE systems.A branched ester-type lithium imide-----lithium bis[(1,1,1,3,3,3-hexafluoro -2-propoxy) sulfonyl] imide (LiN[SO2OCH(CF3)2]2, LiHFPSI) was used as the salt for methoxy ether-substituted poly(organophosphazenes) {NP[(OCH2CH2)XOCH3]2}n (where x = 2~4, MExP) based polymer electrolytes. The maximum conductivity at 25℃ (which varied with the lithium salt concentration) increased as the lengths of the side chains increased, which was in good agreement with the activate energy (Ea) calculated from the VTF equation. In comparison with MExP-LiTFSI (Lithium bis(trifluoromethyl sulfonyl) imide) system, MExP-LiHFPSI had similar conductivities but better electrochemical stabilities, and the bigger size and special structure of the anion would also help to improve the cationic transference number. What’s more, the electrochemical stability window of the SPEs increased along with the increasing number of fluorine-containing groups, which is in accordance with the change of their HOMO energy calculated by PM3 semi-empirical method. The results of the thermal analysis indicated that the glass transition temperature (Tg) of the SPEs prepared in our experiments were very low, and no melting temperature had been found in the temperature range from –100~100℃. As indicated by the TGA result, these materials remains stable up to 200℃ without losing any weight. The optimum system for MExP-LiHFPSI complexes is obtained when x=4 and the molar ratio of Li+ to repeat unit is 3:8 with the highest conductivity of 4.48×10-4 S/cm, which also possessed an electrochemical stability window of more than 6.0V and an excellent thermal stability.A series of SPEs based on lithium poly(polyfluoroalkoxy) sulfonyl imide) were prepared in our experiment. The MEEP-2# salt (lithium poly(4,4’-(hexafluoro isopropylidene) diphenoxy) sulfonyl imide) (mol Li/rpt unit=0.125) system had the best performance, with an conductivity of 2.42×10-5S/cm at 25℃ and an electrochemical stability window of 5.5 V. It also had good thermal stability and good dimensional stability as well. In summary, the polymer electrolytes based on methoxy ether-substituted poly (organophosphazenes) and a novel series of lithium superacid salts would have tremendous potential in the applications of secondary lithium battery and other electrical devices due to their satisfactory ionic conductivities, outstanding electrochemical stabilities and thermal stabilities.