聚氯乙烯断面特征区及粗糙度与断裂能的关系

以往对聚合物材料的断面粗糙度与力学性能关系的研究主要是针对断面总体粗糙度进行的,忽略了断裂的不同阶段及不同的断裂机制在断面上产生的相应的特征区对力学性能参数的影响,导致如文献［１］、［２］中得出的粗糙度参数与断裂能耗间的数据关系存在较大的分散性．本文...     

韧性聚合物材料断面分维与断裂韧性

韧性聚合物材料断面分维与断裂韧性吕素平，漆宗能（中国科学院化学研究所工程塑料国家重点实验室，北京，１０００８０）关键词分维，断裂韧性，聚合物，微裂纹，剪切带利用分形几何定量描述材料断面的粗糙特征［１－４］为建立断面形貌与材料韧性间的定量关系提供了可能...     

聚醚醚酮醚酮的合成与表征

聚醚醚酮（ＰＥＥＫ）自工业化以来［１］，由于其优异的性能已在机械、航天等领域得到广泛应用．各种聚芳醚酮类聚合物相继被开发出来．但以亲电缩聚路线制备聚醚醚酮醚酮（ＰＥＥＫＥＫ）的报道较少［２］．本文以二苯醚和４－氟苯甲酰氯为主要反应试剂，采取付氏酰基化...     

含间位聚醚酮醚酮酮的合成与结晶

聚芳醚酮类聚合物因其综合性能优异而在高技术领域得到广泛应用．这些高聚物的主链大都为全对位连接,使其熔点较高以至加工难度增大．如果在聚合物主链中引入间位结构,则可在对玻璃化转变温度影响较小的情况下降低熔点来改善加工条件［１］．含间位聚醚酮醚酮酮（ＰＥＫＥＫｍＫ）也是其中一种．本文主要研究ＰＥＫＥＫｍＫ的合成、基本物性与结晶行为．样品的合成与制备：单体４,４′双（对苯氧基）二苯甲酮按文献［２］方法合成．聚合物参照文献［３］合成．将粉末样品在油压机上熔融后快速取出投入冰水中淬火得无定形样品,或将熔融…     

金属离子与卟啉的嵌入反应动力学研究──Ⅶ．一元酸根催化Cu(Ⅱ)与溴化间－四(N－乙酸甲酯基－3－吡啶基)卟啉的配位反应

研究了在３５±０．１℃、离子强度０．５ｍｏｌ／Ｌ（ＫＣｌ）条件下，甲酸根、乙酸根、丙酸根和丁酸根分别催化Ｃｕ（Ⅱ）离子与四溴化间－四（Ｎ－乙酸甲酯基－３－吡啶基）卟啉（Ｈ２Ｔβ－Ｎ－ＡＣＭｓｐｙＰＢｒ４）的反应动力学及其机理，该类反应对卟啉和Ｃｕ（Ⅱ）离子均为一级反应，反应动力学方程为：ｄ［ＣｕＰ＾４＋］／ｄｔ＝ｋ｛１．０＋ｂ［Ａ＾－］）／（１．０＋Ｋ３，４．［Ｈ＾＋］＾２｝［Ｃｕ＾２＋］［Ｐ］Ｔ     

色谱灰色数模的建立及其应用研究(Ⅱ)——NLCGM(1,1)模型的建立及芳烃保留行为的预测

色谱保留值与流动相组成间关系的研究一直是色谱工作者关心的课题［１,２］．灰色模型对于处理具有不确定关系的两因素间的关系问题具有独到之处,在容量因子（ｋ）与流动相组成（φ）关系的研究方面已得到了应用［３～８］．传统ＧＭ（１,１）模型将ｋ与φ之间的关...     

聚醚酮酮/含萘环聚醚砜醚酮酮无规共聚物的合成与性能

聚芳醚酮作为一类耐高温特种工程塑料，具有优异的热、电、机械性能，已被广泛应用于电子电器、宇航、原子能工程等高科技领域．对于聚醚醚酮（ＰＥＥＫ）及其改性的研究已有很多报道［１～４］，然而有关主链含萘环的聚芳醚酮的报道较少［５］．前文［６］采用亲电取代路...     

PPV-PDMeOPV共聚物发光性质的实验和理论研究

具有优良电致发光性能的有机聚合物材料的研制及其发光性能和应用的研究是９０年代新兴的高科技领域．聚对苯乙炔［Ｐｏｌｙ（ｐ－ｐｈｅｎｙｌｅｎｅｖｉｎｙｌｅｎｅ）,缩写为ＰＰＶ,又称聚苯撑乙烯］是这一领域最先研制出来的具有代表性的材料［１,２］．为改变ＰＰ...     

C60接枝聚(N-乙烯基咔唑)的合成、表征及光电导性能

自从Ｃ６０被发现和被制备出来以后,其特殊的结构和独特的物理和化学性质受到各研究领域学者的广泛青睐．聚（Ｎ－乙烯基咔唑）（ＰＶＫ）体系经 Ｃ６０掺杂后光电导性能有很大幅度提高．但掺杂体系不稳定,因而限制了对该类材料的应用．为了克服这种缺点,我们尝试用各种简单的方法把Ｃ６０化学键合到高分子链中,制备具有光电导性能的Ｃ６０高分子衍生物． 最近,唐本忠［１］和 Ｐａｔｉｌ［２］等分别用常规的自由基聚合方法,将Ｃ６０接枝到聚合物分子主链上,我们已研究了不含导电高分子的Ｃ６０共聚物的光电导性能［３］,本文采用…     

含萘环聚醚砜醚酮酮的合成与表征

聚芳醚酮是一类综合性能优异的新型热塑性高分子材料，在高科技领域中获得了广泛的应用［１，２］，研制新型的聚芳醚酮是目前十分活跃的课题［３～７］．本文在亲电缩聚合成聚醚酮酮（ＰＥＫＫ）的基础上［８］，利用合成的新单体—４，４－二（β－萘氧基）二苯砜（Ｂ...     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.     

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.