离聚物对含液晶聚合物聚砜体系的增容作用

离聚物对含液晶聚合物聚砜体系的增容作用刘杰，何嘉松（中国科学院化学研究所工程塑料国家重点实验室北京１０００８０）关键词增容作用，离子聚合物，热致液晶聚合物，高分子共混物，原位复合材料工程塑料与液晶聚合物（Ｌｒｙ）共混（形成所谓的原位复合材料）时在降低...     

酸酐化聚砜对聚砜/液晶聚合物共混物的界面增容作用

首先合成了马来酸酐接枝改性聚砜.改性后聚砜材料的表面张力增大,其中的极性分量增加明显,并以此增容聚砜/液晶聚合物(VectraB950)为原位复合体系,研究了增容前后共混物的加工流变行为和界面性能.结果表明,酸酐化聚砜可增强聚砜与液晶聚合物之间的界面作用,引起共混物加工粘度的上升;漫反射FTIR研究表明,增容后共混体系中的特殊相互作用增大;XPS和PLM的研究表明,在熔融加工过程中改性聚砜与液晶聚合物组分之间存在一定的界面化学反应,并生成了接枝共聚物.共混物相容性的提高应归结于相间化学反应与物理作用共同作用的结果.     

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。     

离聚物在液晶聚合物与聚碳酸酯共混体系中的增容作用

离聚物在液晶聚合物与聚碳酸酯共混体系中的增容作用刘杰何嘉松（中国科学院化学研究所工程塑料国家重点实验室北京１０００８０）关键词增容作用，离聚物，热致液晶聚合物原位复合材料（Ｉｎ ｓｉｔｕｃｏｍｐｏｓｉｔｅ）是一种新兴的复合材料，是由热致液晶聚合...     

液晶离聚物的合成

由于液晶离聚物需要在液晶聚合物中引入离子基团，因此造成了合成上的困难，有关液晶离聚物的合成还处于探索阶段。本文综述了液晶离聚物的合成方法，并描述了这些方法所获得的液晶离聚物的规律性的液晶行为。     

含羧基的液晶离聚物

探讨了含有羧酸基液晶离聚物,描述了主,侧链带有羧酸基液晶离聚物,并分别讨论了不同羧酸基含量对碳氢和硅氧烷为主链的侧链带羧酸基液晶离聚物的Tε和Ti的影响.随着羧酸基的增加,对不同类型液晶离聚物Tε的影响规律不同,主要为羧酸基的增加产生不同氢键交联度的结果;同时羧酸基链段的长短也对Tε有重要的影响.随着离子浓度的增加,液晶离聚物的Ti总体呈下降趋势.不同浓度的羧酸基对液晶相和焓变AH也具有影响.     

手性主链液晶离聚物的液晶性能

以6,6'-二羟基麦芽糖六乙酸酯(MA)、4,4'-对羟基联苯酚(MB)、2,5-二羟基苯甲酸(MC)、癸二酰氯(SD)为单体,采用溶液缩聚的方法合成了主链液晶离聚物.通过红外光谱、差示扫描量热及偏光显微等手段,研究了MC含量对液晶离聚物性能的影响.结果表明:液晶聚合物均为热致胆甾型,随MC含量的增加,其玻璃化转变温度、熔点和清亮点呈上升趋势,液晶相逐渐被破坏,羧酸离子的引入没有改变聚合物的液晶相类型.     

液晶离聚物--液晶行为的研究

综述了液晶离聚物中离子的种类,位置、在链中浓度对液晶性能的影响,无论是主链还是侧链液晶离聚物,离子的种类,位置对中介区间的宽度有影响,但对中介相类型基本没有影响,当离子浓度增大到一定值时,液晶性能消失。     

嵌段共聚物增容剂对不相容均聚物共混体系相行为和界面性质的影响

聚合物共混体系(又称聚合物合金)兼具其相应组分的均聚物和共聚物的多种特征,甚至具有新的理想性能,从而成为了一种具有极高经济价值的新材料.该材料的研发极大地丰富了高分子物理学、高分子化学和材料学的研究内容,拓宽了聚合物材料在现代工业中的应用,同时把聚合物材料研究推向了交叉科学的前沿.均聚物/嵌段共聚物/均聚物体系作为经典的三元聚合物共混体系,对其进行深入地研究,不仅可以促进人们对高分子科学中重要问题的理解,而且可为新型嵌段共聚物增容剂的改良和设计提供理论依据.近年来,有关聚合物共混体系的实验、理论和计算机模拟工作很多,并且取得了较大的进展,但是相关综述较少.本文以均聚物/嵌段共聚物/均聚物体系为例,综述该领域的基本概念和发展历史,并着重介绍两嵌段共聚物增容剂对该三元共混体系相行为和界面性质的影响.此外,还介绍了这一领域的关键科学问题、发展前景和研究方向.     

离子聚合物在Nylon－1010／PP共混物中的增容作用

离子聚合物在Ｎｙｌｏｎ－１０１０／ＰＰ共混物中的增容作用曲桂杰，刘景江（中国科学院长春应用化学研究所长春１３００２２）关键词聚丙烯，Ｎｙｌｏｎ－１０１０，离子聚合物，增容选择离子聚合物作为高聚物共混的增容剂，通过离子间的相互作用可达到增容效果［１］。...     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.