交联高分子的分子量分布

从概率母函数出发,利用Lagrange展开,导出了起始分子为Flory和Poisson分布的交联高聚物的分子量分布函数,并用以描述交联分子结构的溶胶分数。     

Liquid Crystalline Polymers

The liquid crystalline behavior of low molecular weight compounds has been known for more than a century; synthetic polymers have been manufactured on a large scale for several decades, but just recently it was found possible to produce polymers using the structural principles of liquid crystalline compounds. The resulting materials have, as expected, unusual properties. Numerous applications, not only in opto-electronics, are already anticipated for such materials.     

Liquid Crystalline Polymers

History of Liquid Crystalline PolymersThe liquid crystalline(LC)state was first observed by Austrian botanist and chemist F.Reinitzer more than a century ago,and it was then confirmed in 1888 by German physicist O.Lehmann who named such a state of matter as"liquid crystal"in 1900.While low molecular mass(LMM)liquid crystals were successfully used in LC displays(LCDs),the development of LC polymers(LCPs)followed an independent path.Conceptually,LCPs are prepared with the incorporation of mesogenic groups that are responsible for the formation of LC mesophases,such as rod-like(calamitic)and discotic ones,into polymer chains.Depending on where the mesogens are attached,traditionally there are three major categories of LCPs.Main-chain LCPs(MCLCPs)have mesogens in the polymer backbone,while mesogens of side-chain LCPs(SCLCPs)are incorporated as side groups in a polymer with a relatively flexible main chain.In main-chain/side-chain combined LCPs(MCSCLCPs),mesogens are in both the backbone and side chains.Other classes of LCPs include mesogenjacketed LCPs(MJLCPs),dendronized LCPs,and LC networks(LCNs).     

一个判别液晶聚合物状态的新方法

伴随液晶相转变而产生的转变焓、转变熵可提供有关各相的结构、状态及有序度等信息.本文从动力学、热力学角度分析了液晶聚合物从各向同性熔体冷却时系统的热熵变化,建立了液晶聚合物升降温过程中的热熵图,提出了定量判断液晶聚合物从各向同性熔体冷却后所处状态的新方法.     

Molecular Weight Distribution of Living Radical Polymers

Summary: The molecular weight distribution formed in an ideal living radical polymerization is considered theoretically. It was found that the hypergeometric function that combines the most probable and the Poisson distribution represents a fundamental distribution of the living radical polymers. The number‐ and weight‐average molecular weights are derived for this fundamental distribution, together with those for polymerizations in a batch and in a continuous stirred tank reactor. These average molecular weight functions are obtained based on the arithmetic calculations without deriving the distribution functions. The effect of the monomer transfer reactions on the formed MWD is also considered. The present study clarifies the relationship between the reaction mechanism and the formed molecular weight distribution as well as the fundamental characteristics of living radical polymers.

Calculated number fraction distribution N(r) development with (dashed) and without (solid) the monomer transfer reactions.     

Fundamental Molecular Weight Distribution of RAFT Polymers

The molecular weight distribution formed in an ideal reversible addition‐fragmentation chain transfer (RAFT)‐mediated radical polymerization is considered theoretically. In this polymerization, the addition to the RAFT agent is reversible, and the active period on the same chain could be repeated, via the two‐armed intermediate, with probability 1/2. This possible repetition is accounted for by introducing a new concept, the overall active/dormant periods. With this method, the apparent functional form of the molecular weight distribution (MWD) reduces to that proposed for the ideal living radical polymers (Tobita, Macromol. Theory Simul. 2006 , 15, 12). The repetition results in a broader MWD than without the repetition. The formulae for the average molecular weights formed in batch and a continuous stirred tank reactor are also presented.

     

组装合成超分子液晶聚合物动态功能材料

从电荷转移相互作用。离子相互作用及氢键组装三个方面综述了通过分子自组装合成超分子液晶聚合物近年来的最新研究成果。总结 阴谋家类体系作为动态功能材料在器件化及应用方面所取得的重要进展，并展望了这一领域今后的发展方向。     

分子量对壳聚糖溶致液晶性的影响

三种不同分子量的壳聚糖[脱乙酰度均为(84±1)%]在二氯乙酸溶液中都呈现胆甾型溶致液晶相.临界浓度随分子量增加而降低,但均比同样聚合度的甲壳素的高.用偏光显微镜法和激光小角散射法测得的胆甾液晶相的螺距很相近,在浓度相同时,其值随分子量的增加而减小.     

液晶聚合物材料的红外光谱表征

红外光谱以高选择性、无破坏性以及高超的分辨和实时跟踪能力成为从分子水平研究液晶聚合物的的重要分析手段,而偏振二向色技术、时间分辨步扫描技术和二维相关分析技术的发展进一步提高了红外光谱分析复杂液晶聚合物的能力。本文介绍了传统傅里叶变换红外光谱及各种新型光谱分析技术（主要是二维相关技术）对液晶聚合物材料表征的研究进展,特别是对于液晶聚合物分子氢键、共聚和共混物相容性以及外场（温度、电场、光场、应力场）作用下液晶分子取向等的研究,并分别进行了具体的应用实例分析。     

甲壳型液晶高分子研究进展

介绍了近年在甲壳型液晶高分子的设计、合成、表征以及结构与性能关系探索方面的进展,对今后的研究方向提出了粗浅的看法。     

发光液晶高分子:分子构筑、结构与性能及其应用

发光液晶高分子结合了液晶高分子的有序性、稳定性、力学性能和发光分子的发光特性,有着广阔的应用前景。为了获得高效的发光液晶高分子,不同结构的发光液晶高分子被成功地设计与合成,包括主链型、侧链型、“甲壳”型发光液晶高分子、发光液晶高分子网络等。同时,分子结构、液晶相结构与光物理性质的关系也得到了相应的深入研究。本文总结了发光液晶高分子的最新研究进展,详细介绍了不同类型发光液晶高分子的分子结构设计合成、结构与性能、相关应用,并对其发展前景进行了展望。     

发光性液晶共轭聚合物的研究进展发光性液晶共轭聚合物的研究进展

综述了可用做发光材料的液晶共轭聚合物（LCCPs)的种类及其制备,介绍了LCCPs在制备发光器件中的取向方法,并对其光学性能进行了评述。     

疏水缔合聚合物分子量分布曲线的测定

在体积百分浓度为50%1,3-丙二醇、0.2 mol/L Na Cl和水溶剂条件下,消除疏水缔合聚合物(HAWSP)溶液中疏水缔合作用,屏蔽溶液中的聚电解质效应,使HAWSP分子在稀溶液中处于单分子分散状态.然后利用膜孔径分离原理,选择不同孔径的微孔滤膜,用微孔滤膜流动实验装置对疏水缔合聚合物进行分级,将不同分子量的聚合物分离开来.用二次方程拟合滤出液质量-过滤时间关系曲线得到各级分聚合物溶液的质量,以分光光度法测定各级分聚合物溶液的浓度,根据质量和浓度计算得到各级分的累积百分含量.结合静态光散射和毛细管法标定了疏水缔合聚合物Mark-Houwink方程[η]=0.182M~(0.586),用于准确测定疏水缔合聚合物各个级分的分子量.选择四参数方程曲线,根据各级分的分子量M和累积百分含量W,得到分子量的分布曲线.与动态光散射分析进行比较的结果表明,两种方法测试结果一致.     

含季铵离子液晶聚合物

详细讨论了带有铵离子的液晶聚合物的合成与性能,以及铵离子对聚合物液晶性能的影响。研究表明,液晶相温度的增加是由铵离子在聚合物链中浓度的增加而引起的。     

A Facile Method for Controlling the Molecular Weight of Hyperbranched Light‐Emitting Polymers

Summary: Two series of hyperbranched conjugated polymers were synthesized via an A₃ + B₂ type Wittig reaction. The molecular weights of the polymers were successfully tuned by simply changing the feed ratio of the monomers. Polymers with higher molecular weights presented more efficient photoluminescence, higher thermal stability and higher performance of LEDs.

     

Osmometric Molecular Weight Determinations of Peptides Using o-Chlorophenol

Abstract

Osmometric molecular weight determinations of peptides carried out at 37° using o-chlorophenol as solvent have been found to be precise with the exception of determinations involving peptides containing free carboxyl groups.     

含液晶聚合物的原位复合材料中界面相容性的改善策略

综述了近年来含液晶聚合物的原位复合材料中增容技术的一些进展,主要了四种增容技术,即加入具有增容作用的第三组分;在分散相液晶聚合物的主链上引入与基体树脂主链中相同或相似的单元,酯交换反应和多元共混技术,简要描术字原位复合材料的发展趋势。     

Synthesis of Liquid Crystalline Polymers with Side Chains

The present paper covers the synthesis and characterization of several intermediate products, monomer, and polymers. 3-{ 2-[ 4-( 4-Nitrophenylazo ) phenoxy] ethyloxycarbonyl} propanoyloxy (2-hydroxy) propyl acrylate (4) was prepared by the ring-opening reaction of glycidyl acrylate with the monoester of succinic acid (3). The polymers (5) with different molecular weights were prepared by the free-radical polymerization. The polymers (5) had liquid crystalline behavior without decomposition as revealed by DSC, optical microscope.     

液晶金属配位聚合物的合成及性能

基于国内外最新研究文献 ,系统论述了近年来液晶金属配位聚合物的合成方法、液晶行为及应用前景。指出液晶金属配位聚合物的合成方法可归纳为直接配位法、单体配位法、交联配位法和聚合物反应法四种。液晶金属配位聚合物一般呈现热致液晶行为 ,显示稳定的向列液晶相或近晶液晶相。有些金属配位聚合物还呈现互变性近晶态或单变液晶性。液晶金属配位聚合物具有金属的特殊性质 ,是一种新型高性能磁导、电导和光导材料 ,可望应用于液晶显示材料、磁性信息储存薄膜材料、润滑剂和各向异性催化剂等。