PPO-PDMS-PHS_n三元多嵌段共聚物的形态结构和性能

利用DMA,TEM和SAXS对以聚苯醚(PPO)为硬段、聚对羟基苯乙烯(PHS)为半硬段和聚二甲基硅氧烷(PDMS)为软段的三元多嵌段共聚物(?)PPO-PDMS-PHS(?)_n的形态结构和性能进行了研究.结果表明,(?)PPO-PDMS-PHS(?)_n以三种嵌段相容相为连续相,PPO与PHS的相容相和PDMS相为两种分散相,其tanδ随温度变化曲线在-100℃至200℃一直是一很高的平台,并具有优异的力学性能,较好地解决了含有机硅类嵌段共聚物强度低的弱点,同时又保留了嵌段共聚物微相分离的特性.

(Z)-1[2-(苯基二溴化锡基)乙烯基]-1-环己醇的合成及晶体结构

报道了标题化合物〔C14H18Br2OSn〕的合成及晶体结构。该晶体属于单斜晶系，空间点群为P21/c，晶胞参数a=11.711(2)，b=9．114（2），c=16．864（3）A，β=102.94（1）°，V=1604.55（0）A3，Mr=480．78，Z=4，Dc=1．99g／cm3，u=65．20cm－1，F（000）=919，R=0．050，Rw=0．050．晶体结构由直接法解出。标题化合物分子中的锡原子被配体的2个碳、2个溴和1个氧原子配位，配位原子呈畸变的三角双锥构型，环已基为椅式构象，五员杂环为信封构象。

Ln(η~6-m-C_6H_4Me_2)(AlCl_4)_3,(Ln=Pr,Er)的合成及Pr配合物的晶体结构

ＬｎＣｌ３（Ｌｎ＝Ｐｒ，Ｅｒ）与ＡｌＣｌ３在二甲苯中反应，合成了η６－（ｍ－Ｍｅ２Ｃ６Ｈ４）Ｌｎ（ＡｌＣｌ４）３这两个新配合物并对其进行了元素分析、红外光谱和质谱的表征。测定了Ｐｒ配合物的晶体结构。该配合物具有扭曲的五角双锥几何构型。二甲苯和一个氯原子处于两个顶点，Ｐｒ配合物属单斜晶系，空间群Ｐ２１／ｎ，晶胞参数为ａ＝９．８７０（３），ｂ＝１６．７９４（８），ｃ＝１６．０２５（７），β＝９４．４０（３）°，Ｖ＝２６４８．５１３，Ｚ＝４。平均Ｐｒ－Ｃ为２．９５（２）。

CaAl_3BO_7:RE(RE=Ce,Gd,Tb)中稀土离子的光谱特性

采用固相反应法合成了ＣａＡｌ３ＢＯ７ＲＥ（ＲＥ＝Ｃｅ，Ｇｄ，Ｔｂ），研究了Ｃｅ３＋，Ｇｄ３＋和Ｔｂ３＋的光谱特性．发现铈离子周围存在较强的晶场，使基态的４ｆ能级劈裂较大，从而导致铈离子的特征发射峰重叠较大；Ｃｅ３＋的５ｄ能级明显低于Ｇｄ３＋的６Ｉ、６Ｐ能级；Ｃｅ３＋和Ｔｂ３＋之间存在有效的能量传递

THEORETICAL-STUDIES ON THE CYCLIZATION PROCESS OF A NEW ORGANOSULFUR REACTION

The cyclization process of a new organosulfur reaction was studied by the MNDO (UHF) method. The first reaction path was assumed to be via the organosulfur radical intermediate, the second via the ionic (cationic and anionic) intermediates. The dehydroxylation process was assumed to occur with the synergistic cyclization. The results obtained indicate that the potential energy barrier of the first reaction path was about 102 kcal mol(-1), and although the formation of the ionic intermediate is comparatively difficult, the potential energy barrier of the second path is comparable to the first. The sequential reaction path via the radical intermediate, i.e. first cyclization, then dehydroxylation, was investigated for comparison. The cyclization reaction was found to be the thermodynamically favored process, while the ensuing dehydroxylation process was found to have a potential energy barrier of about 62 kcal mol(-1).

裂解色谱法测定环化顺1,4聚丁二烯的环化度

用裂解色谱法(PGC)研究了不同环化度的环化顺1,4聚丁二烯(CPBd)。建立了测定CPBd环化度的方法。分析了不同实验条件下生成的CPBd的环化度,结果与NMR测定值一致。

DETERMINATION OF HYDRAZINES BY CAPILLARY ZONE ELECTROPHORESIS WITH AMPEROMETRIC DETECTION AT A PLATINUM PARTICLE-MODIFIED CARBON-FIBER MICROELECTRODE

A novel modified electrode dispersed with ultrafine platinum particles on the surface of a 30-mu m carbon fibre microelectrode was investigated as an amperometric detector in capillary zone electrophoresis (CEEC) for determining hydrazines. The unique cha

MICROSTRUCTURE ANALYSIS OF 3 SEGMENTED COPOLYMERS CONTAINING POLYDIMETHYLSILOXANE BY SOLID-STATE HIGH-RESOLUTION NMR

The microstructure of two bicomponent and one tricomponent segmented copolymers, based on polydimethylsiloxane, poly(p-hydroxystyrene) or/and polysulfone, were investigated using an extended Goldman-Shen pulse sequence, proton spin-spin relaxation measurements, and C-13 and Si-29 NMR spectra. The results indicate that there exist four phases with different sizes, components and morphological structure in the segmented copolymers studied in this work, i. e., a rigid-chain phase of very slow motion, a rigid-chain-rich phase of slow motion, a flexible-chain-rich phase of fast motion and a flexible-chain phase of faster motion. The sizes of different domains, calculated from the spin diffusion rates, are about 50-100 angstrom for the flexible-chain-rich phase of fast motion and 200-300 angstrom for the flexible-chain phase of faster motion. The relative quantities of polydimethylsiloxane in the flexible-chain phase of fast motion are slightly different in different kinds of segmented copolymers.

STUDY ON STRUCTURE-PROPERTY RELATIONSHIP OF POLYIMIDE BLENDS .2. STRUCTURE AND MISCIBILITY OF POLYIMIDE PBPI-E/PTI-E BLENDS

The structure and miscibility of polyimide PBPI-E/PTI-E blends were studied by wide- and small-angle X-ray scattering and dynamic mechanical analysis, where PBPI-E is a biphenyl-dianhydride-based polyimide, and PTI-E is a polyimide from 4,4'-thiodiphthalic anhydride and 4,4'-oxydianiline. The results obtained show that there exists a paracrystalline structure in the blends with high content of PBPI-E, but this does not affect the miscibility of the blends. The blends are miscible over the entire composition range, since only one T(g) was observed for each blend. Meanwhile, the segregation of PTI-E during crystallization of PBPI-E in the blends is interlamellar.

UNSTEADY DIFFUSION KINETICS OF ZIEGLER-NATTA HETEROGENEOUS CATALYST POLYMERIZATION .4. PREDICTION OF EXPERIMENTAL RESULTS OF PROPYLENE ETHYLENE 1-HEXADECENE TERPOLYMERIZATION

The prediction, based on unsteady diffusion kinetics, of the enhancement of reactivity and incorporation of 1-hexadecene in its copolymerization with propylene on adding a small amount of ethylene (increase from 5,2 mol-% to 10,8 mol-% when 2% of ethylene was added, and to 16,1 mol-% when 5% was added) was verified in the terpolymerization of propylene/1-hexadecene/ethylene on a commercial Solvay-type delta-TiCl3 catalyst. The catalyst efficiency was thus also increased. These augmentations originate from the increase in diffusion coefficient of 1-hexadecene at the catalyst surface when the PP crystallinity decreases on introduction of ethylene. Calculation based on unsteady diffusion kinetics showed that the order of diffusion coefficients ethylene > propylene > 1-hexadecene is reversed as the monomer concentration increases when the monomers are not at their equilibrium concentration. Sequence distribution as determined by means of C-13 NMR revealed a tendency of blocky structure rather than a Bernoullian one. The terpolymer compositions obtained by means of an IR method developed in this work conform rather well with the NMR results. Results in this work not only support the unsteady diffusion kinetics but also provide a new route to prepare olefinic copolymer rubbers with heterogeneous titanium catalysts.

FACTORS AFFECTING THE ROLE OF SIO2 IN MGCL2-SUPPORTED ZIEGLER-NATTA COPOLYMERIZATION CATALYSTS

This paper describes the roles of silica (SiO2), the butoxy ligand (-OBu) and ethyl benzoate (EB) on ethylene/1-butene copolymerization with MgCl2/SiO2-supported titanium catalysts. The distribution of SiO2 and of the elements Mg and Ti was observed by means of an energy-dispersed X-ray microanalyzer on a scanning electron microscope (SEM). An inversed Si/Mg ratio results, at invariant Ti/Mg ratio and -OBu content, in higher catalyst efficiency and higher comonomer incorporation, with a correspondingly decreased crystallinity of the copolymers. Thus, the inert carrier SiO2 favors copolymerizability, as seen from the values of the reactivity ratios. The copolymer compositional distribution is also affected by the SiO2 content, as seen from the DSC curves of the copolymers. As to the copolymer morphology, addition of SiO2 makes the copolymer particles larger and more uniform.

A NEWLY PROPOSED MOLECULAR TOPOLOGICAL INDEX FOR THE DISCRIMINATION OF CIS/TRANS ISOMERS AND FOR THE STUDIES OF QSAR/QSPR

A new topological index, the general a(N)-index (GAI), on quantum chemistry, is described in this paper. The GAI can be applied to molecules that contain heteroatoms and multiple bonds, and performs well in distinguishing cis/trans isomers. The relationships between the GAIs and physicochemical properties of olefins and neutral phosphorus compounds were observed with satisfactory results.

抗氧剂和应力对EPDM/CIIR并用胶热氧老化性能的影响

研究了抗氧剂1010和2246及压缩应力对第三单体为双环戊二烯(DCPD)的乙丙橡胶/氯化丁基橡胶(EPDM_D/CIIR)和第三单体为乙叉降冰片烯(ENB)的乙丙橡胶(EPDM_B)/CIIR两种并用胶热氧老化性能的影响。认为抗氧剂能显著改善EPDM_D/CIIR的力学性能和热氧老化性能,压缩应力能影响EPDM_E/CIIR的使用寿命。

热处理对HDPE/iPP共混物中附生结晶的影响

木工作用透射电子显微术研究不同热处理温度对HDPE/iPP共混物溶液浇铸薄膜中附生结晶的影响。经热处理的共混物薄膜HDPE片晶尺寸明显增加,但其长轴仍与iPP成约50°夹角。电子衍射和暗场的实验结果及样品倾斜技术的利用证明了在iPP的两种结构区域中HDPE均在iPP上异相附生生长,两者的接触面为iPP的(010)和HDPE的(100)。在194℃热处理20min,然后自然冷却的HDPE/iPP共混物薄膜中的HDPE仍然在iPP上附生生长。