Studies on Novel Polymer Materials Prepared through Intermacromolecular Complexation

The basic feature of polymers is their multi-order structure. Structure change at each level offers a possibility tomodify polymer properties and to develop new polymer materials. Therefore,novel polymer materials can be developed by tailoring their chain structure through chemical bonding among atoms, i.e., via the traditional molecular chemistry methods, e.g., polymerization of new monomer, controlling chain length (molecular weight and molecular weight distribution) and stereoregularity, copolymerization of different kinds of monomers, controlling sequence distribution,block of graft length of copolymer, etc., which have been the focus of polymer chemistry for several decades, as well as by tailoring specific supramolecular architecture using molecules as building block through intermolecular interactions, i.e., via supramolecular science methods, e.g., molecular self-assembly, intermacromolecular complexation, etc., which is a modern and fast-developing academic research field.This paper reports novel polymer materials prepared through intermacromolecular complexation,e.g., a new polymer solid electrolyte poly(metyl methacrylate-methacrylic acid)[P(MMA-MAA)]/poly(ethylene oxide) (PEO)/A2-LiClO4 developed by intermacromolecular complexation through hydrogen bonding, which has enhanced ambient ionic conductivity and fairly good mechanical and film-forming properties, a new polymer microcomposite poly(acrylonitrile-acrylamide-acrylic acid) [P(AN-AM-AA)]/poly(vinyl alcohol) (PVA) reinforced by the twin molecular chain microfibrils formed through intermacromolecular complexation of P(AN-AM-AA) with PVA through hydrogen bonding, which exhibits much better mechanical properties than its constituents and could be used to manufacture PVA based complexed fibers with higher modulus and better dyeability, a new polymer flooding agent poly(acrylamide-acrylic acid)[P(AM-AA)]/poly(acrylamide- dimethyldiallylammonium chloride) [P(AM-DMDAAC)] developed by intermacromolecular complexation of the oppositely charged polyions through Coulomb forces,which shows much higher viscosity and better resistance to temperature, shear rate and salt than its constituents, and has potential application in enhanced oil recovery.     

PEO-LiClO_4-ZSM5复合聚合物电解质II.ZSM-5对离子电导率的影响

通过XRD ,DSC ,FT IR和SEM等方法对PEO LiClO4 ZSM5复合电解质进行了研究 ,结果表明ZSM 5可以有效地降低PEO LiClO4 ZSM5复合电解质中PEO的结晶度和玻璃化温度 ,从而提高其低温区域的离子电导率 .温度高于PEO的结晶熔融温度后 ,复合电解质离子电导率的提高则是由于在ZSM 5表面形成了有利于Li离子迁移的导电通道所引起的 .较高的离子电导率和较宽的电化学稳定窗口表明PEO LiClO4 ZSM5复合电解质在全固态锂离子二次电池领域具有良好的应用前景 .     

Al2O3掺杂的复合聚合物电解质室温电导研究

1973年 Wright等[1] 首先报道了 PEO-Li+ 盐的固态聚电解质体系 ,我们从 90年代开始研究物质在聚合物电解质中的传输机理及固 -固界面动力学等问题 [2～ 4 ] .由于聚合物电解质易成膜 ,在制备高能密度全固态电池和光电化学器件等方面具有广泛的应用前景 .目前研究的聚电解质主要为通过加入金属盐而具有导电性的聚合物材料 .PEO具有良好的机械性能和化学稳定性 ,从而成为研究最为广泛的高分子材料 .金属盐溶于 PEO后 ,易形成晶态复合物 ,其电导率仅为 1 0 - 7～ 1 0 - 8S/cm,与应用中所要求的 1 0 - 3 S/cm相差甚远 .因此 ,如何提高 PE…     

阻抗虚部计算聚合物电解质电导率

用交流阻抗法研究了（PEO1）10LiClO4-Al2O3和（PEO2）16LiClO4－碳酸乙烯酯（EC）两种复合物电解质体系的电导率，给出了等效电路和各拟合元件的物理意义。当阻抗谱图发生严重变形时，提出一种比较简单的计算聚合物电解质电导率的方法－－阻抗虚部最大值法。     

聚环氧乙烷与聚2-乙烯基吡啶混物的导电率及高氯酸锂的增容作用

研究了聚环氧乙烷(PEO)/聚2-乙烯基吡啶(P2VP)的共混物分别经LiCLO₄、四氰基代苯醌二甲烷(TCNQ)及两者共同掺杂后其共混物的离子、电子及混合导电率。当PEO与P2VP的重量比分别为6/4、5/5及4/6时,共混物的混合导电率大于相应的离子及电子导电率的总和,呈现协同效应。从共混物外观的研究发现LiCLO₄能作为PEO/P2VP共混体系的增容剂。     

Synthesis and Characterization of a Novel Polymer Electrolyte for Lithium-ion Battery

A novel polymer electrolyte with the formula of Li2B4O7-PVA for lithium-ion battery was synthesized and its ion conductivity and mechanical properties were also tested. It is found that the conductivity of the prepared polymer electrolytes is higher than that of LiClO4/PEO or LiClO4/EC-DMC by two or three orders in magnitude and a large delocalized bond formed in Li2B4O7-PVA lead to transportation of Li ion easier, this electrolyte possesses high thermo-stability and can be used under 200℃.     

PEO-LiClO_4-ZSM5 composite polymer electrolyte (IV): Polarized optical microscopy study

All solid-state lithium polymer batteries may be one of the best choices for the future electrochemical power source, characterized by high energy densities, good cyclability, reliability and safety[1,2]. Owing to its potential capability to replace the t…     

相态结构对聚氧化乙烯/丁二腈/高氯酸锂复合电解质室温电导率的影响

采用聚氧化乙烯(PEO)、丁二腈和高氯酸锂(LiClO4)的复合电解质体系, 制备了一系列不同配比的PEO/SN/LiClO4复合电解质, 对其室温电性能和相态结构进行了表征, 并探讨了相态结构对室温电导率的影响.     

Segmental dynamics of PEO/LiClO4 complex crystals and their influence on the Li+-ion transportation in crystal lattices: A 13C solid-state NMR approach

The structure and chain dynamics of polyethylene oxide (PEO)/LiClO(4) complex crystals were studied by employing state-of-the-art solid-state (13)C NMR techniques. Remarkable helical jump motions of the PEO segments in the complex crystals at ambient temperatures were clearly demonstrated. The jump motions are believed to induce the transportation of the coordinated Li(+) ions along the crystallographic c axis, providing a novel mechanism of ionic conductivity of the complex crystals. In addition, this work also shows that solid-state high-resolution (13)C NMR spectroscopy can be a powerful and general tool for elucidating phase structures, dynamics, and subsequently the conduction mechanism of crystalline polymer electrolytes.     

Study of microstructural characterization and ionic conductivity of a chemical-covalent polyether-siloxane hybrid doped with LiClO4

The chemical-covalent polyether-siloxane hybrids (EDS) doped with various amounts of LiClO4 salt were characterized by FT-IR, DSC, TGA, and solid-state NMR spectra as well as impedance measurements. These observations indicate that different types of complexes by the interactions of Li+ and ClO4- ions are formed within the hybrid host, and the formation of transient cross-links between Li+ ions and ether oxygens results in the increase in T(g) of polyether segments and the decrease in thermal stability of hybrid electrolyte. Initially a cation complexation dominated by the oxirane-cleaved cross-link site and PEO block is present, and after the salt-doped level of O/Li+ = 20, the complexation through the PPO block becomes more prominent. Moreover, a significant degree of ionic association is examined in the polymer-salt complexes at higher salt uptakes. A VTF-like temperature dependence of ionic conductivity is observed in all of the investigated salt concentrations, implying that the diffusion of charge carrier is assisted by the segmental motions of the polymer chains. The behavior of ion transport in these hybrid electrolytes is further correlated with the interactions between ions and polymer host.     

PEO/LiClO_4纳米SiO_2复合聚合物电解质的电化学研究

将实验室制备的纳米二氧化硅和市售纳米二氧化硅粉末与PEO LiClO4复合 ,制得了复合PEO电解质 .它们的室温离子电导率可比未复合的PEO电解质提高 1～ 2个数量级 ,最高可以达到 1 2 4× 10 - 5S cm .离子电导率的提高有两方面的原因 :一是无机二氧化硅粉末的加入抑制了PEO的结晶 ,是二氧化硅粉末和聚合物电解质之间形成的界面对电导率的提高也有一定的作用 .在进一步加入PC EC(碳酸丙烯酯 碳酸乙烯酯 )混合增塑剂后制得的复合凝胶PEO电解质 ,可使室温离子电导率再提高 2个数量 ,达到 2× 10 - 3 S cm .用这种复合凝胶PEO电解质组装了Li|compositegelelectrolyte|Li半电池 ,并测量了该半电池的交流阻抗谱图随组装后保持时间的变化 ,实验观察到在保持时间为 144h以内钝化膜的交流阻抗迅速增大 ,但在随后的时间内逐渐趋于平稳 ,表明二氧化硅粉末的加入可以有效地抑制钝化膜的生长     

聚氧化乙烯/高岭石聚合物电解质的制备与表征

通过尿素对高岭石的插层及随后的超声脱除处理,制备了一种片层剥离的高岭石粉体,并将这种剥离高岭石与聚氧化乙烯/高氯酸锂(PEO/LiClO_4)体系复合,制备出PEO/高岭石复合物.采用X射线衍射仪、红外光谱仪、扫描电子显微镜、透射电子显微镜、扫描量热仪、电化学工作站和万能材料试验机进行结构表征和性能测试.结果表明,尿素在高岭石层间的插层和脱除引起了高岭石片层的剥离,片层厚度小于50 nm.剥离高岭石在PEO/LiClO_4体系中与PEO形成了强烈的氢键作用,促进了PEO结晶度的降低,进而提高复合物的离子电导率.含有20 wt%剥离高岭石填料的PEO/高岭石复合物的离子电导率达到6.0×10~(-5) S/cm,与未复合的PEO/LiClO_4相比,提高了一个数量级.复合物制备过程中的烘干温度对PEO的结晶度会产生一定的影响,95°C下的烘干处理能得到结晶度较低,离子电导率较高的复合物.此外,剥离高岭石的添加显著提高了聚合物的杨氏模量和拉伸强度,与未复合的PEO/LiClO_4相比,杨氏模量和拉伸强度最大提高了256%和121%.     

Blends of POSS-PEO(n=4)(8) and high molecular weight poly(ethylene oxide) as solid polymer electrolytes for lithium batteries

Solid polymer electrolyte blends were prepared with POSS-PEO(n=4)8 (3K), poly(ethylene oxide) (PEO(600K)), and LiClO4 at different salt concentrations (O/Li = 8/1, 12/1, and 16/1). POSS-PEO(n=4)8/LiClO4 is amorphous at all O/Li investigated, whereas PEO(600K) is amorphous only for O/Li = 8/1 and semicrystalline for O/Li = 12/1 and 16/1. The tendency of PEO(600K) to crystallize limited the amount of POSS-PEO(n=4)(8) that could be incorporated into the blends, so that the greatest incorporation of POSS-PEO(n=4)(8) occurred for O/Li = 8/1. Blends of POSS-PEO(n=4)(8)/PEO(600K)/LiClO4 (O/Li = 8/1 and 12/1) microphase separated into two amorphous phases, a low T(g) phase of composition 85% POSS-PEO(n=4)(8)/15% PEO(600K) and a high T(g) phase of composition 29% POSS-PEO(n=4)(8)/71% PEO(600K). For O/Li = 16/1, the blends contained crystalline (pure PEO(600K)), and two amorphous phases, one rich in POSS-PEO(n=4)(8) and one rich in PEO(600K). Microphase, rather than macrophase separation was believed to occur as a result of Li(+)/ether oxygen cross-link sites. The conductivity of the blends depended on their composition. As expected, crystallinity decreased the conductivity of the blends. For the amorphous blends, when the low T(g) (80/20) phase was the continuous phase, the conductivity was intermediate between that of pure PEO(600K) and POSS-PEO(n=4)(8). When the high T(g) (70/30, 50/50, 30/70, and 20/80) phase was the continuous phase, the conductivity of the blend and PEO(600K) were identical, and lower than that for the POSS-PEO(n=4)(8) over the whole temperature range (10-90 degrees C). This suggests that the motions of the POSS-PEO(n=4)(8) were slowed down by the dynamics of the long chain PEO(600K) and that the minor, low Tg phase was not interconnected and thus did not contribute to enhanced conductivity. At temperatures above T(m) of PEO(600K), addition of the POSS-PEO(n=4)(8) did not result in conductivity improvement. The highest RT conductivity, 8 x 10(-6) S/cm, was obtained for a 60% POSS-PEO(n=4)(8)/40% PEO(600K)/LiClO4 (O/Li = 12/1) blend.     

含锂沸石Li-FER提高PEO复合聚合物电解质电导率

通过离子交换方法使锂部分取代了镁碱沸石（FER）孔道壁上羟基中的氢，制得含锂沸石Li-FER. 将这种沸石作为无机填料加入到PEO/LiClO₄聚合物电解质中，可以使其室温电导率提高三个数量级以上. 电化学测量表明， 锂离子与PEO和含锂沸石中氧的相互作用提高了聚合物电解质中锂离子的迁移数. 另一方面， 采用XRD, DSC, PLM等方法研究了电解质的结晶状况.结果表明, Li-FER可以作为PEO链段结晶的成核剂，使PEO电解质的晶粒得到细化， 结晶度降低，为Li⁺的传输提供了更多的非晶区通道. 这是Li-FER的加入促使PEO聚合物电解质电导率提高的两个主要原因.     

Molecular dynamics simulation of the polymer electrolyte poly(ethylene oxide)/LiClO(4). II. Dynamical properties

The dynamical properties of the polymer electrolyte poly(ethylene oxide) (PEO)LiClO(4) have been investigated by molecular dynamics simulations. The effect of changing salt concentration and temperature was evaluated on several time correlation functions. Ionic displacements projected on different directions reveal anisotropy in short-time (rattling) and long-time (diffusive) dynamics of Li(+) cations. It is shown that ionic mobility is coupled to the segmental motion of the polymeric chain. Structural relaxation is probed by the intermediate scattering function F(k,t) at several wave vectors. Good agreement was found between calculated and experimental F(k,t) for pure PEO. A remarkable slowing down of polymer relaxation is observed upon addition of the salt. The ionic conductivity estimated by the Nernst-Einstein equation is approximately ten times higher than the actual conductivity calculated by the time correlation function of charge current.     

含烷氧磺酸锂盐及对称星形醚的聚环氧乙烷基聚合物电解质的制备及电化学性能

合成了低聚度烷氧磺酸锂盐（LiSA(EO)n)和对称星形醚（STEO）增塑剂,并制备了聚环氧乙烷（PEO）基聚合物电解质。 研究了PEO16+LiSA(EO)n体系的锂离子迁移数和电导率与锂盐结构的关系,实验结果表明,LiSA(EO)n代替LiClO4作为锂盐时,其电导率得到提高,而且聚合物电解质的锂离子迁移数随着烷氧磺酸锂盐阴离子体积的增大而增加,并且其中PEO16+LiSA(EO)2体系的锂离子迁移数达到0.35。 STEO可明显地提高PEO16-LiSAEO-STEO体系的电导率,PEO16-LiSAEO-20%STEO室温电导率可达到0.5×10-4 S/cm。 通过DSC实验结果表明,STEO的加入,可有效降低聚合物电解质体系的熔融温度和结晶度,PEO16-LiSAEO-20%STEO电化学稳定窗口在4.4 V以上,可满足锂电池的应用要求。     

聚丙烯酸/聚氧化乙烯高分子复合溶液的结构与粘度

通过溶液折光指数和粘度测定,研究了聚丙烯酸（ＰＡＡ）与聚氧化乙烯（ＰＥＯ）高分子链间在复合溶液中的相互作用和ＰＡＡ／ＰＥＯ高分子氢键复合溶液的结构与粘度,研究了复合溶液粘度随溶液ｐＨ值的变化规律及不同浓度时剪切速率对复合溶液粘度和复合增粘效果的影响。结果表明：ＰＡＡ／ＰＥＯ复合溶液结构不同于ＰＡＡ和ＰＥＯ两组分聚合物溶液结构,ＰＡＡ与ＰＥＯ高分子链间的氢键相互作用形成构象更为伸展、流体力学体积列大     

Plasticized polymer electrolyte membranes based on PEO/PVdF-HFP for use as an effective electrolyte in lithium-ion batteries

Plasticized polymer electrolytes were prepared using poly(ethylene oxide)(PEO)/poly(vinylidene fluoridehexafluoro propylene)(PVd F-HFP) with lithium perchlorate(Li Cl O4) and different plasticizers. XRD and FTIR spectroscopic techniques were used to characterize the structure and the complexation of plasticizer with the host polymer matrix. The role of interaction between polymer hosts and plasticizer on conductivity is discussed using the results of alternating current(a.c.) impedance studies. TG-DTA and SEM were used for thermal and physical characterizations. Maximum ionic conductivity(3.26 × 10~(-4) S·cm~(-1)) has been observed for ethylene carbonate(EC)-based polymer electrolytes. Electrochemical performance of the plasticized polymer electrolyte is evaluated in LiFePO_4/plasticized polymer electrolytes(PPEs)/Li coin cell. Good performance with low capacity fading on charge discharge cycling is demonstrated.     

Viscosity enhancement of complexed solutions formed through the complexation of nonionic water‐soluble polymers with chemically complementary structures in aqueous media

The intermacromolecular complexation of polymers with chemically complementary structures in aqueous media is a new approach to modifying polymer solutions, especially to enhance solution viscosity. In this study, complexed solutions formed through the hydrogen‐bonding complexation of several nonionic water‐soluble polymer pairs—poly(acrylic acid) (PAA) with polyacrylamide (PAM), PAM with poly(ethylene oxide) (PEO), PAA with poly(vinyl alcohol) (PVA), and PEO with PVA—were prepared, and the viscosity enhancement of the complexed solutions were studied with vision spectrophotometry and viscometry. The effects of the polymer concentration, polymer molecular weight, and pH value of the polymer solution on the intermacromolecular interactions were investigated through a comparison of the viscosity enhancement factor R of different complexed solutions. The results show that the viscosity of the PAA/PAM complexed solution is much higher than that of its constituents, whereas that of the PAM/PEO and the PAA/PVA complexed solutions are between the viscosities of their constituents but are higher than the theory values calculated from the blending rule of two polymer solutions. These results indicate that in the complexed solutions there exist interactions between the macromolecules with chemically complementary structures, although the interactions are quite different for the different complexed systems. It is the interactions that lead to an association of the polymers and, hence, an obvious enhancement in the solution viscosity and the resistance of the polymer solutions to shearing. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1069–1077, 2000     

Ion conduction and polymer dynamics of poly(2-vinylpyridine)-lithium perchlorate mixtures

Ion conduction and polymer dynamics of homogeneous mixtures of poly(2-vinylpyridine) (P2VPy) with 0.1 to 10 mol % lithium perchlorate (LiClO(4)) were investigated using broadband dielectric spectroscopy. Interpretation of the relaxation behavior was assisted by findings from differential scanning calorimetry, Fourier transform infrared spectroscopy, dynamic mechanical analysis, and wide-angle and small-angle X-ray scattering experiments. Five dielectric relaxations were observed: a local beta-process in the glassy state, a segmental relaxation, a slow segmental process, an ion-mode relaxation, and electrode polarization. The local P2VPy beta-relaxation was strongly suppressed with increasing LiClO(4) content arising from the formation of transient crosslinks, which lead to a subsequent decrease in the number of free pyridine groups and/or a reduction in the local free volume in the presence of LiClO(4). Ion conduction at low LiClO(4) concentrations (<10 mol %) is governed by the diffusion of anions through the matrix, which is strongly coupled with the segmental relaxation. At relatively high LiClO(4) concentration (10 mol %), partial decoupling between ion motion and the segmental relaxation was observed, leading to increased conductivity.