嵌段离聚物的制备及其络合和缔合性质

报道了一种氢化ＳＢＳ（ＳＥＢＳ）的化学改性方法，由此得到了一种基于ＳＥＢＳ的离聚物，其中ＰＳ嵌段接有少量羧酸盐基．用动态光散射和粘度法表征了基于ＳＥＢＳ的不同配对离子的磺酸离聚物在非极性溶剂中的缔合行为，给出了缔合物存在的证据和缔合物尺寸的定量数据．ＳＥＢＳ磺酸盐离聚物与含吡啶基的无规共聚物在稀溶液和本体中能形成分子间的络合物，这从共混物溶液粘度的反常增大和本体Ｔｇ的显著增加得到了证明．用粘度法、透射电子显微镜表征和证实了ＳＥＢＳ羧酸钠离聚物在水中可以形成稳定的胶体分散．疏水粒子为表面的离子基团所稳定．     

含液晶离聚物共混体系的研究进展

液晶离聚物(liquid crystalline ionomers,LCIs)是一种具有液晶性能的离聚物,也可以说是带有离子基团的液晶聚合物.将液晶离聚物与其它热塑性聚合物熔融共混时,其既能起到液晶聚合物的高模量、高强度作用,同时也具有离子的增容剂作用.本文论述了液晶离聚物在共混体系中的研究进展.按照液晶离聚物所含离子的不同,论述了含有-COOH,-SO3H和≡N+ 的液晶离聚物对共混体系的增容和增强作用.考察了液晶离聚物对共混体系热力学性能、形态结构和力学性能的影响.     

聚左旋乳酸遥爪离聚物的静态结晶及剪切诱导结晶行为

遥爪离聚物体系由于易形成相对均匀的可逆网络，受到高性能材料领域学者的广泛关注。通过引入磺酸根和Na+反离子，设计合成了一种分子链轻微缠结的聚左旋乳酸遥爪离聚物，由于离子聚集的“锚定”作用，其静态结晶动力学显著延迟。通过时温叠加得到的样品线性黏弹准主曲线显示出宽平台和末端松弛延迟的特点，这反映了强缔合的特点。在韦森堡数大于1的剪切流场作用下，该材料表现出剪切增稠和结晶加速行为。研究发现，增稠是剪切诱导结晶引起的，增稠可能发生在两个区域，即在剪切应力稳定之前或者之后，并且增稠发生在剪切应力稳定之后所需的临界功明显更高，这可能与稳定后缔合点连续的解离和再缔合导致的能量损耗相关。     

阴离子型离聚物的研究进展

参考近年来文献资料,总结了磺酸型、羧酸型、膦酸型等阴离子型离聚物的合成方法,对离聚物的几种重要聚集态结构模型进行了介绍,对于文献报道的各种模型在应用方面的不足之处也进行了总结。对于离聚物形态结构,介绍了有关微相分离方面的研究以及利用电镜技术得到的新突破。在离聚物的溶液性质方面,介绍了溶液粘度和溶剂作用的相关研究。对于离子对含量和类型等因素对离聚物力学性能和玻璃化转变温度的影响进行了总结,最后指出了离聚物尚需进一步研究的问题。     

聚苯醚离聚体/聚(苯乙烯-co-4-乙烯吡啶)共混体系的溶液行为

聚（２，６ 二甲基 １，４ 苯醚）（ＰＰＯ）离聚体（磺化或羧化聚苯醚）／聚（苯乙烯 ｃｏ ４ 乙烯吡啶（ＰＳＶＰ）共混物的溶液行为研究表明，与对应的ＰＰＯ／ＰＳＶＰ共混物相比，这两个系列的共混物都表现出较高的比浓粘度．这是由于聚苯醚离聚体上的酸基发生质子转移，产生了酸根阴离子和吡啶基阳离子，两组分间的酸 碱相互作用导致了分子间的缔合，从而使比浓粘度提高．     

轻度磺化聚苯乙烯与聚苯乙烯共混物的流变性能表征

采用DSR-200动态应力流变仪研究了磺化度为0.98%(摩尔分数)的轻度磺化聚苯乙烯(SPS)离聚物及其锌盐(ZnSPS)与聚苯乙烯(PS)的共混物(PS/SPS,PS/ZnSPS)的流变性能.由于离聚物中离子聚集的物理交联作用,使其流变性能与PS相比有明显差别.动态频率实验结果表明,所有样品均可采用时温等效处理.另外,在与分子链运动相关的低频区,由于离子聚集的作用使得离聚物的模量远大于PS的模量.离聚物在稳态剪切作用下,由于离子聚集的破坏而表现出明显的屈服现象,并能用Utracki的屈服应力公式表征其屈服应力和零切粘度.此外,离聚物的屈服现象还与温度相关.由于动态和稳态实验分别测试离子聚集存在和破坏的不同材料状态,因此对离聚物无法应用Cox-Merz规则.动态和稳态实验结果均表明,PS/SPS和PS/ZnSPS的性能与组成的变化规律不同,意味着二者之间存在不同的离子聚集结构或相互作用.     

离聚物共混研究进展

综述了十 多年来。人们旨在提高相容性及其它一些性能，将离聚物引人共混体系所展开的系列研究。总结出，离聚物共混体系中，离聚物起增容作用的根本原因是在共混休整 系中引入了一些特殊的离子相互作用：离子－离子作用，离子－偶极作用，过渡金属离子的配位作用，介绍了目前研究离聚物共混的主要方法。     

离聚物在质子交换膜燃料电池膜电极中的应用进展

离聚物是质子交换膜燃料电池(PEMFC)膜电极(MEA)中的重要组成部分之一.它不仅作为将质子和水从阳极转移到阴极的离子交换膜,更重要的是还在催化剂层中起黏合剂、气体输送和质子传递的作用.本文分析了膜电极催化剂层中离聚物的特点和所起的关键作用,重点强调了离聚物在催化剂墨水和催化剂层中的微观结构及其与催化剂层中其他组成的相互影响.该综述对于低成本的新型无氟离聚物的设计和功能化具有重要意义,以期最终能取代价格昂贵的全氟磺酸(PFSA)离聚物.     

离聚物型自修复高分子材料的研究进展

自修复是指材料在受到损伤后可自行修复,并在一定程度上恢复其力学性能的特性,对提高材料的使用寿命及安全性具有重要意义。离聚物中的离子基团在一定条件下由于静电相互作用及与主链的不相容性而相互聚集,形成动态可逆的物理交联点,从而赋予了离聚物材料在无外加修复剂的条件下即可实现自修复的特性。本文系统评述了离聚物型高分子材料的自修复过程与机理、常用的离聚物体系、激发离聚物自修复行为的方式及影响离聚物自修复特性的因素。     

"标记"芘的激基缔合物荧光在水溶性高分子研究中的应用

首先介绍了芘的荧光发射光谱的特点及其激基缔合物荧光、然后给出了用芘标记高分子的各种方式和方法,讨论了水溶性高分子的”标记”芘形成激基缔合物的原理,评述了芘标记高分子箕缔合物荧光在水溶性分子疏水相互作用,静电相互作用、氢键、络合等研究中的应用,也介绍了芘标记激基缔的荧光在高分子凝胶体积相变、分子链运动等领域的研究进展。     

Ionomer-surfactant self-assembly in low-polarity solvents

A systematic study of complexation reactions of sulfonated polystyrene ionomers containing up to 5 molar percent of polar chain units with various oil-soluble surfactants is carried out in low-polarity organic solvents. Dipole-dipole attractions of the components lead to the formation of complexes characterized by limiting compositions and an unusual polymer-colloidal morphology of joint clusters and/or micelles. The limiting compositions (φ) for the complexes formed between ionomers and surfactant of the same charge (bis(2-ethylhexyl)sulfosuccinate sodium salt), or nonionic surfactants (primarily aliphatic amines) are equal to 15–30 surfactant molecules per one ionomer salt/acid group on average, with φ depending on the hydrophilic-lypophilic balance of the components, the initial aggregation state of surfactant and the nature of low-polarity solvent. Ionomersurfactant complexation is accompanied by disruption of self-contacts of ionomer salt/acid groups, leading to “unfastening” and expansion of the ionomer coils in dilute solution. The “driving force” of the ionomersurfactant complexation and the structure of the resultant complexes are discussed.     

Solution properties of ionomers. I. Counterion effect

The effect of counterions on the solution properties of two types of ionomers, one based on sulfonated polystyrene and the other based on styrene–methacrylic acid copolymer, was studied by viscosity and light scattering measurements. It was found that the order of counterion binding of ionomers in a polar solvent and the order of aggregation of ionomers in a low-polarity solvent were the same for the same ionomer system. However, the order for the sulfonated ionomer was Li < Na < K < Cs, whereas that for the carboxylated ionomer was the opposite. This can be explained by a difference in desolvation during anion–cation interaction and by considering site-binding in a polar solvent and the association of ion pairs in a low-polarity solvent. These findings for ionomer systems are parallel to the association behavior of small ions in water, cation affinity in crosslinked resins, and counterion binding of polyelectrolytes in water.     

Complexation between sodium dodecyl sulfate and amphoteric polyurethane nanoparticles

The complexation between negatively charged sodium dodecyl sulfate (SDS) and positively charged amphoteric polyurethane (APU) self-assembled nanoparticles (NPs) containing nonionic hydrophobic segments is studied by dynamic light scattering, pyrene fluorescent probing, zeta-potential, and transmission electron microscopy (TEM) in the present paper. With increasing the mol ratio of SDS to the positive charges on the surface of APU NPs, the aqueous solution of APU NPs presents precipitation at pH 2, around stoichiometric SDS concentration, and then the precipitate dissociates with excess SDS to form more stable nanoparticles of ionomer complexes. Three stages of the complexation process are clearly shown by the pyrene I1/I3 variation of the complex systems, which only depends on the ratio of SDS/APU, and demonstrate that the process is dominated by electrostatic attraction and hydrophobic aggregation.     

嵌段离聚物的缔合和络合行为(Ⅲ)──基于SEBS的嵌段离聚物和含吡啶基聚合物间的相互作用

制备了一系列基于氢化SEBS的嵌段离聚物(BCI),研究了具有不同金属对应离子的BCI分别和含聚乙烯吡啶基的无规共聚物MVP和SVP的共混物的溶液粘度和本体的热行为.结果表明,MVP和SVP可与BCI的PS离子化嵌段形成络合物,导致T_g增加且远高于FOX方程预示值,同时比浓粘度远高于加合性预示值.在所研究的金属离子中,Ni和Cu显示最佳的络合能力.     

Complexation of poly(acrylic acid) and poly(ethylene oxide) investigated by enhanced Rayleigh scattering method

The method of enhanced Rayleigh scattering spectroscopy (ERS) was developed to investigate the complexation of poly(acrylic acid) (PAA) and poly(ethylene oxide) (PEO) in semidilute polymer solutions. Based on the Ornstein‐Zernike equation, the relationship between macromolecular static correlation length and ERS intensity was presented. Moreover, the ERS spectra were calculated by the moving window two‐dimensional (MW2D) correlation spectroscopy to get detailed information of the polymer complexation. The results indicated that the ERS spectroscopy characteristics of the polymer mixtures have similar trend, and the ERS intensity promptly increases as the macromolecular chains contract. The increase of ERS intensity showed that the degree of complexation between PAA and PEO increases when the pH value decreases. The complexation results from the collapse of macromolecular chains, which is induced by the PAA chains contracting and the enhanced association between PAA and PEO chains because of the hydrogen bond formation. In addition, the association resulting from the complexation of PAA and PEO in solution was demonstrated by the MW2D correlation spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1847–1852, 2010     

A Magnesium-Selective Ionophore Containing Four Amide Carbonyl Ligands Derived from L-Tartaric Acid and Axial Furano Oxygen Binding Sites

Octahedrally converging hexadentate macrocyclic receptors 1 and 2, based on L-tartaric acid and furanmoieties, were synthesized andtheir complexation properties studied. In this paper,magnesium ion selectivitiesdetermined by ISE experiments, chiroptical changes observedby circular dichroism(CD) on complexation, and association constants measuredby NMR titration arediscussed.     

The effect of cations on nucleophilic additions to carbonyl compounds: carbonyl complexation control versus ionic association control. application to t

The fundamental influence of cations in nucleophilic additions to carbonyl compounds is discussed in terms of either carbonyl complexation or ionic association with the nucleophile. Since loose ion pairs react essentially under complexation control while tight ion pairs react under association control, an experimental criterion is proposed to determine which factor controls the reactivity (complexation or association) based on the kinetic effects of cryptand or crown-ether addition.An application of this duality is then examined for the regioselectivity of nucleophilic additions to α-enones and correlated with perturbational arguments based on abinitio calculations. Under complexation control, attack at carbon 2 is favoured, especially when a soft nucleophile is involved and the counter-ion is Li⁺ rather than Na⁺. Under association control two cases are considered according to whether the cation is directly bound or not to the nucleophilic center; in addition, the influence of hard or soft metals and the possibility of a cationic bridge in the transition state have been discussed. Several kinetic controlled reactions have been examined and interpreted in this way. An extension of this concept to other reactions will be considered.     

Electroptical and dynamic properties of sulfonated polystyrene molecules and their associates in chloroform

The behavior of sulfonated PS containing 0.5, 1.35, 2.6, and 5.8 mol % of sodium sulfonate groups in chloroform solutions has been studied by static and dynamic light scattering, viscometry, and electric birefringence. The molecular mass of ionomers is measured, and their translational diffusion coefficient, intrinsic viscosity, and free relaxation times are estimated. It has been shown that association in solutions of ionomers containing more than 1.35 mol % of sodium sulfonate groups proceeds according to the open association model. Analysis of autocorrelation functions of scattered light intensity and electric birefringence decay makes it possible to determine translational diffusion coefficients and relaxation times for individual ionomer molecules, their pair associates, and higher multiplicity associates. With an increase in the fraction of sodium sulfonate groups, the hydrodynamic radius of individual ionomer molecules decreases from 8 to 5.8 nm, while the ratio between the hydrodynamic radius of pair associates and individual sulfonated PS molecules increases.     

Blends of polycarbonate and ethylene-1-octylene copolymer

The mechanical properties and morphology of polycarbonate/ethylene-1-octylene copolymer (PC/POE) binary blends and PC/POE/ionomer ternary blends were investigated. The tensile strength and elongation at break of the PC/POE blends decreased with increasing the POE content. The impact strength of the PC/POE blends showed less dependence on thickness than that of PC. And the low-temperature impact strength of PC was modified effectively by addition of POE. The morphology of the PC/POE blends was observed by scanning electron microscope. The PC/POE weight ratio had a great effect on the morphology of the PC/POE blends. For the PC/POE (80/20)/ionomer ternary blends, low content (0.25 and 0.5 phr) of ionomer could increase the tensile properties of PC/POE (80/20) blend and had little effect on the impact strength. And 0.5 phr ionomer made the dispersed domain distribute more uniformly and finely than the blend without it. But with high content of ionomer, the degradation of PC made the mechanical properties of the blends deteriorate. Blending PC and ionomer proved the degradation of PC, and the molecular weight decreased with increasing the ionomer content.