Self-organization of interlaced network lamellar crystals of trans-1,4-polybutadiene (TPBD) on an amorphous surface

A novel morphology of TPBD crystals consisting of a three-dimensional interlaced network was obtained by casting the self-seeded 0.1% benzene solution onto carbon-boated mica. Both the transmission electron microscopy (TEM) and electron diffraction (ED) analyses showed that the network was composed of well-developed lamellae. It is imagined this interesting morphology is the results of asymmetrical growth of the original TPBD lamellae on the amorphous interface, and that their preferred orientation changed when they encountered each other.

Size-affected crystallization of trans-1,4-polybutadiene

By using different catalyst systems, two trans-1,4-polybutadiene (TPBD) samples with different tr trans-content and molecular weight were synthesized. The phase transition of two samples from monoclinic form to hexagonal phase was revealed by differential calorimeter scanning and X-ray, respectively. The small-angle X-ray scattering measurements showed the remarkable discrepancy of phase transition and melting point between the two samples was attributed to the different lamellar thickness of crystals: The crystals with different crystalline morphology and lamellar thickness were developed by casting different concentration TPBD solutions. Transmission electron microscopy morphology observations proved that annealing the specimen at the temperature above the phase transition point for different times resulted in the different lamellae thickening of monoclinic form. It means that annealing the TPBD in its hexagonal phase will also slightly favor the increase of both the phase transition temperature and melting point of hexagonal phase. (C) 2001 Elsevier Science Ltd. All rights reserved.

Effect of electron radiation on crystal structure transition of trans-1, 4-polybutadiene

trans-1,4-Polybutadiene (PTBD) was synthesized by rare earth catalyst system, The effect of electron radiation on phase transition from monoclinic phase to hexagonal phase was observed by TEM, Electron diffraction patterns of monoclinic phase, hexagonal phase and two coexistent phases were recorded, The mechanism of phase transition was also discussed in this paper.

Effect and mechanism in compatibilization of poly(styrene-b-2-ethyl-2-oxazoline) diblock copolymer in poly(2,6-dimethyl-1,4-phenylene oxide) poly(ethylene-ran-acrylic acid) blends

The compatibilization effect of poly(styrene-b-2-ethyl-2-oxazoline) diblock copolymer, P(S-b-EOx), on immiscible blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and poly(ethylene-co-acrylic acid) (EAA) is examined in terms of phase structure and thermal, rheological and mechanical properties, and its compatibilizing mechanism is investigated by Fourier-transform infrared spectroscopy. The block copolymer, synthesized by a mechanism transformation copolymerization, is used in solution blending of PPO/EAA. Scanning electron micrographs show that the blends exhibit a more regular and finer dispersion on addition of a small amount of P(S-b-EOx). Thermal analysis indicates that the grass transition of PPO and the lower endothermic peal; of EAA components become closer on adding P(S-b-EOx), and the added diblock copolymer is mainly located at the interface between the PPO and EAA phases. The interfacial tension estimated by theological measurement is significantly reduced on addition of a small amount of P(S-b-EOx). The tensile strength and elongation at break increase with the addition of the diblock copolymer for PPO-rich blends, whereas the tensile strength increases but the elongation at break decreases for EAA-rich blends. This effect is interpreted in terms of interfacial activity and the reinforcing effect of the diblock copolymer, and it is concluded that the diblock copolymer plays a role as an effective compatibilizer for PPO/EAA blends. The specific interaction between EAA and polar parts of P(S-b-EOx) is mainly hydrogen bonding. (C) 1998 Elsevier Science Ltd. All rights reserved.

镍催聚1,4-聚丁二烯橡胶的e_y,[Z]和f值与其内在的相关性

比较稀土催聚1，4—聚丁二烯橡胶和几种不同温度下聚合的镍催聚1，4—聚丁二烯橡胶的σｙ 和［η］，从中得知链缠结的变化是影响σｙ 和［η］以及 τ的主要原因，而微观结构的变化可能是影响链缠结的因素之一，1，4—聚丁二烯橡胶的加工性能与链缠结有关。

Compatibilizing effect of polystyrene-block-poly(4-vinylpyridine) for poly(2,6-dimethyl-1,4-phenyleneoxide) chlorinated polyethylene blends

The compatibilizing effect and mechanism of compatibilization of the diblock copolymer polystyrene-block-poly(4-vinylpyridine) P(S-b-4VPy) on immiscible blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)/chlorinated polyethylene (CPE) were studied by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC), mechanical properties and FTIR measurements. The block copolymer was synthesized by sequential anionic polymerization and melt-blended with PPO and CPE. The results show that the P(S-b-4VPy) added acts as an effective compatibilizer, located at the interface between the PPO and the CPE phase, reducing the interfacial tension, and improving the interfacial adhesion. The tensile strength and modulus of all blends increase with P(S-b-4VPy) content, whereas the elongation at break increases for PPO-rich blends, but decreases for CPE-rich blends. The polystyrene block of the diblock copolymer is compatible with PPO, and the poly(4-vinylpyridine) block and CPE are partially miscible.

异丙基膦酸单(1-已基-4-乙基)辛酯的某些基本常数的测定

用两相滴定法测定异丙基膦酸单(1-己基-4-乙基)辛酯(PT-2,HL)在水中的溶解度S，在水中的解离常数K在水-正庚烷中的分配常数Kd及二聚常数K2，利用SOLWR计算程序，简单快速地处理两相滴定数据，得到结果为：S=3.68×10-5mol/L，pKa=5.49，logK2=4.67，logKd=2.67(25±0.5℃)

Gas permeation properties of copolyimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride

A series of aromatic copolyimides was prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoroisopropane dianhydride (6FDA) with 3,3'-dimethyl-4,4'-methylene dianiline (DMMDA) by a chemical imidization. The gas permeability coefficients of the copolyimides to H-2, CO2, O-2, N-2 and CH4 were measured under 7 atm. pressure. The fractional free volume of 6FDA-DMMDA is larger than that of HQDPA-DMMDA, while the chain segmental mobility of 6FDA-DMMDA is lower than that of HQDPA-DMMDA. The gas permeability of 6FDA-DMMDA is much higher than that of HQDPA-DMMDA but the permselectivity of 6FDA-DMMDA for H-2, CO2, O-2, N-2 over CH4 is lower than that of HQDPA-DMMDA. The experimental values of the gas permeability coefficients of the copolyimides are in satisfactory agreement with the values estimated from the gas permeability coefficients of the constituent homopolyimides and their weight fractions.

Gas separation properties of aromatic polyetherimides from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride and 3,5-diaminobenzic acid or its esters

The gas transport properties of a series polyetherimides, which were prepared from 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with 1,3-phenylenediamine or 3,5-diaminobenzic acid (DBA) or its esters are reported. The effects of carboxylic group (-COOH) and carboxylic ether groups (-COOR), at five positions of 1,3-phenylenediamine moiety, on H-2, CO2, O-2, and N-2 permeability, diffusivity, and solubility of the polyetherimides were investigated. The gas permeability, diffusion, and solubility coefficients of the polyetherimides containing COOR are bigger than those of HQDPA-PDA, but the ideal separation factors and ideal diffusivity selectivity factors are much smaller than that of HQDPA-PDA because COOR decreases chain segmental packing efficiency and increases chain segmental mobility. The permeability coefficients of HQDPA-DBA to H-2, CO2, and O-2 are bigger than those of HQDPA-PDA; the ideal separation factors for gas pairs H-2/N-2, CO2/N-2, and O-2/N-2 are also much bigger than those of HQDPA-PDA. Both the diffusion coefficients of CO2 and O-2 and the ideal diffusivity selectivity factors for CO2/N-2 and O-2/N-2 are bigger than those of HQDPA-PDA because COOH decreases both chain segmental packing efficiency and chain segmental mobility. The copolyimides, which were prepared from 3,5-diaminobenzic acid and 3,5-diaminobenzic esters, have both high permeability and high permselectivity. (C) 1997 John Wiley & Sons, Inc.

1,4-二羟蒽醌红外光谱的振动分析

测量了１，４－二羟基蒽醌及其氘代物的红外光谱，用ＮＲＣＣ程序进行了振动分析。由于同时考虑了分子内与分子间的氢键，统一处理面内与面外振动，计算结果优于文献报道，并纠正了一些错误归属。

高效离心分配色谱仪对异丙基膦酸单(1-己基-4-乙基)-辛酯-稀土萃取体系的研究

首次用高效离心分配色谱仪（ＨＰＣＰＣ）研究用异丙基膦酸单（１－己基－４－已基）辛酯（ＰＴ－２）分离三价重稀土元素，以分离 Ｙｂ（Ⅲ）， Ｅｒ（Ⅲ）及 Ｌｕ（Ⅲ）为例，考察了流动相酸度、流速、固定相浓度、ＨＰＣＰＣ的转速等因素对ＨＰＣＰＣ分离稀土效果的影响，并用ＨＰＣＰＣ法和液－液萃取法研究了ＰＴ－２萃取重稀土的机理。

异丙基膦酸单(1-己基-4-乙基)辛酯萃淋树脂吸萃重稀土元素(Ⅲ)

本文研究了异丙基膦酸单（１－己基－４－乙基）辛酯萃淋树脂在盐酸介质中对重稀土元素（Ⅲ）的吸萃平衡，考察了平衡水相酸度对吸附反应的影响，计算了重稀土（Ⅲ）间的平均分离系数，确定了吸附反应的Ｆｒｅｕｄｌｉｃｈ等温吸附方程。该树脂吸附Ｙｂ（Ⅲ）的静态饱和容量为６６．５ｍｇＹｂ／（ｇ．Ｒ），饱和萃合物的ＩＲ谱表明ＰＴ－２萃淋树脂吸附Ｙｂ（Ⅲ）的反应为阳离子交换反应。

异丙基膦酸单(1-己基-4-乙基)辛酯上胺205-正庚烷乳状液膜分离钪(Ⅲ)、铁(Ⅲ)、镥(Ⅲ)

本文研究了异丙基膦酸单（１－己基－４－乙基）辛酯（简称ＰＴ－２）上胺２０５－正庚烷乳状液膜分离钪（Ⅲ），铁（Ⅲ），镥（Ⅲ）及外相酸度、表面活性剂浓度、流动载体浓度和内相酸度对Ｓｃ（Ⅲ）、Ｆｅ（Ⅲ）、Ｌｕ（Ⅲ）迁移影响。实验结果表明，在一定的条件下Ｓｃ（Ⅲ）有可能实现与Ｆｅ（Ⅲ）、Ｌｕ（Ⅲ）的分离。

1,4-二丙氧基-2,3-二氰基萘的合成

以1，4－萘醌为原料，经溴化、氰化、烷基化合成了1，4－二丙氧基－2，3－二氰基萘，用SiemensP4四圆衍射仪测得了晶体结构。合成方法简便，反应时间短，产率高。