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81.
The study deals with the analysis of diffusion and mass transfer modelling during pervaporation in a true ternary system involving a polar liquid mixture (ETBE/EtOH) and a polar block copolymer (polyurethaneimide or PUI). A survey of methods of pervaporative transfer modelling in ternary systems is first developed. From differential permeation experiments carried out with both pure liquids, it appears that both permeants obey a Fickian law. Moreover, the diffusional behaviour is consistent with Long's model, which has thus been assumed for the related ternary system. An extension of the Brun's model is then derived, which takes into account the diffusion coupling as well the significant deviation from sorption ideality. From a practical point of view, the calculated values of fluxes show generally good agreement with the experimental results, although a small deviation occurs for mixtures of low ethanol content. Diffusion coefficients of both pure solvents corresponding to transient or steady state are compared. A very good agreement is found for the aprotic permeant (ETBE). whereas the diffusion coefficient of ethanol in transient state is only the quarter of the value corresponding to steady state. The results are discussed in comparison with related investigations in the literature, involving specific liquid-polymer interactions. 相似文献
82.
Gy. Marosi R. Lágner Gy. Bertalan P. Anna A. Tohl 《Journal of Thermal Analysis and Calorimetry》1996,47(4):1155-1161
Nucleating and transcrystallization behaviour of additives in engineering PP composites and the effect of modified interfacial structure is the subject of this series of papers. The first part concentrates on polypropylene/liquid crystalline polyester blends. Increased crystallisation temperature and degree of crystallinity of polypropylene is characteristic to the blends containing different amount of LCP additive. Transcrystallization process governs the formation of crystalline structure in these systems in course of isothermal crystallisation at 132C. The nucleating effect of LCP gives rise to more uniform crystalline structure in the polypropylene phase.The financial support of the OTKA 014194 is acknowledged with gratitude. 相似文献
83.
84.
LiCl—HOAc和LiCl—HOAc—H2O体系(25℃)相图 总被引:2,自引:0,他引:2
测定了LiCl-HOAc和LiCl-HOAc-H_2O体系25℃时的溶度,绘制了溶度图.在LiCl-HOAc体系的相图中有LiCl及LiCl·1/2HOAc2种固相,后者是固液异成分化合物,体系中未发现LiCl·5HOAc或LiCL·HOAc的生成.LiCl-HOAc-H_2O体系25℃时的相图中有3种固相,即LiCl·H_2O、LiCl和LiCl·(1/2)HOAc.相变LiCl·H_2O→LiCl→LiCl·(1/2)HOAc表明HOAc在该三元体系中具有盐溶、脱水和溶剂合3种作用.此结果提供了一种制备无水LiCl的新方法. 相似文献
85.
Thermal behaviour of blends based on N,N'-bis(4-itaconimidophenyl) ether (IE) and 4,4'-bis(4-allyl-2-methoxyphenoxy) benzophenone
(R1) or 4,4'-bis(2-allylphenoxy) benzophenone (R2) are described in this paper. The reactive diluent content was varied from 5-50% (mass/mass) in these blends. A decrease
in the melting point and exothermic peak temperature was observed with increasing mass percent of reactive diluent. Thermal
stability of blends was affected at high mass percentage of reactive diluents.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
86.
87.
Summary In this work, an optimization procedure for gradient RPLC separation, using ternary mobile phases, is described. This procedure requires eight preliminary experiments in gradient elution mode to predict the retention surface for each solute over the whole triangular space. This is followed by computerized calculations to determine the best ternary gradient elution profile with respect to both selectivity and analysis time. The efficiency of this procedure from the point of view of rapidity and of accuracy, is illustrated for the specific separation of twelve phenyl urea herbicides. 相似文献
88.
Ultra-high-molecular-weight polyethylene (UHMWPE) – carbon black (CB) blends were prepared by gelation/ crystallization from
PE dilute solutions containing CB particles. The UHMWPE/CB composition chosen were 1/0.15, 1/0.25, 1/0.5, 1/0.75, 1/1, 1/3,
1/5, and 1/9, etc. The cross-linking of PE chains was performed by chemical reaction of dicumyl-peroxide at 160 °C. X-ray diffraction patterns indicate that the crystallinity of PE within the blends decreased drastically through the chemical
reaction at high temperature. The sample preparation method by gelation/crystallization provided the UHMWPE–CB system with
various CB contents up to 90% and the conductivities for the resultant specimens were in the range from 10-9 to 1 Ω-1 cm-1 corresponding to the electric conductivity range of semiconductors. The blends assured thermal stability of electric conductivity
by cross-linking of PE chains, although the mechanical property such as the storage and loss moduli were very sensitive to
temperature. The conductivity of the blends with CB content ≥20% were almost independent of temperature up to 220 °C and the values in the heating and cooling processes were almost the same. On the other hand, for the UHMWPE–CB blends with
13% CB content corresponding to the critical one, temperature dependence of electric resistivity showed positive temperature
coefficient (PTC) effect. The PTC intensities for non-cross-linked and cross-linked materials were lower than that of the
corresponding low-molecular-weight-polyethylene (LMWPE)–CB blend but the maximum peak appeared at 160 °C which is higher than the peak temperature of LMWPE–CB blend.
Received: 10 December 1997 Accepted: 9 April 1998 相似文献
89.
Yuandong Wu 《Journal of solid state chemistry》2005,178(5):1569-1574
The new ternary alkali tantalum polysulfide K2Ta2S10 has been synthesized by reacting TaS2 with an in situ formed melt of K2S3 and S at 773 K. The compound crystallizes with four formula units in the monoclinic space group P21/n (No. 14) with lattice parameters of . The structure contains two different zigzag chain anions [TaS5]−, running parallel to the crystallographic b-axis separated by potassium cations. The two crystallographically independent tantalum atoms are in a distorted bi-capped trigonal prismatic environment of eight sulfur atoms which was never observed before. The TaS8 polyhedra share three S atoms on each side to form the anionic chains. The compound was characterized with FIR and Raman spectroscopy. 相似文献
90.
Ba8Cu16P30 – a New Ternary Variant of the Clathrate I Type Structure Ba8Cu16P30 (a = 14.117(1) Å, b = 10.093(1) Å, c = 28.022(2) Å) was prepared by heating a mixture of the elements (800°C; excess of Ba and P; removal of the by-products by acetic acid/H2O2). The compound crystallizes orthorhombically (Pbcn; Z = 4) in a new superstructure of the cubic clathrate I type structure with an ordered distribution of the atoms. The structure is characterized by a three-dimensional framework of CuP4 tetrahedra with cavities in the form of pentagonal dodecahedra and tetrakaidecahedra, which are occupied by the Ba atoms. The compound shows semiconduction, therefore the composition should be Ba8Cu15.5P30.5. 相似文献