STUDY ON THE MECHANISM OF NYLON 6, 6 DISSOLVING PROCESS USING CaCl_2/MeOH AS THE SOLVENT

A discussion of the mechanism of nylon 6, 6 dissolving process using CaCl_2/MeOH as the sol-vent is presented. The calcium chloride forms a complex compound with nylon 6, 6 by breakingthe hydrogen bonds. The melting point of the CaCl_2 --nylon 6, 6 complex was found to be reducedby 91K relative to the pure nylon 6, 6 polymer. The role of methanol is somewhat similar to acatalyst. The results demonstrate that the complexation of a Lewis acid (CaCl_2) and a Lewis base(nylon 6, 6) can be used to probe intermolecular interactions such as hydrogen bonding in polymers, to modify the polymer properties and mediate its solubility and processing.

THE SIMULATION OF LIQUID DISTRIBUTION BASED ON MARKOV PROCESS

The Markov process with discrete state and time is used to simulate the distribution of liquid flow in apacked column.The theoretical prediction agrees well with the experimental data.

SOME THEORETICAL PROBLEMS OF ANIONIC POLYMERIZATION OF BUTADIENE——A Study on the Association Degree of n-BuLi and Polybutadienyl-Li

This paper determined the association degree of n-BuLi and polybutadinyllithium(PBLi)by UV spec-trometry and viscometry.The experimental results of UV spectrometric analysis showed that the associationdegree of n-BuLi as well as PBLi is dependent mainly on their concentration in solutions;there may be specieswith three and two degrees of association in cyclohexane solvent respectively for n-BuLi and PBLi,i.e.the asso-ciation degree for the former is equal to 2,4 and 6;and for the latter it equals to 2 and 4.Similarly,the experi-mental results obtained by viscometric measurement showed that the average association degree N of PBLiin cyclohexane changed from 2 to 4 with increasing of its concentration in solution and decreased with addi-tion of a small amount of polar additive into the above mentioned system.Furthermore,in pure polar solvent,such as dimethoxyethane(DME),tetrahydrofuran(THF)or dioxane(DOX),PBLi is completely dissociatedinto monomeric species;however,in pure diethyl ether,due to its weak polarity a part of associated species stillcan be found.Generally speaking,all of the above results were consistent with the results of kinetic studies in-vestigated by us before.

STUDIES ON THE RELATIONSHIP BETWEEN THE NETWORK STRUCTURE AND THE MECHANICAL PROPERTIES OF RUBBER VULCANIZATES (H) THE REINFORCEMENT OF ELASTOMERS BY CARBON BLACK FILLERS AND ITS CHARACTERIZATION

A satisfactory account of reinforcement of rubber through the application of the theory of elasticity forits vulcanizates with carbon black fillers has been obtained. A statistical theory of reinforcement by carbonblack fillers and its characterization was developed. Three methods

AN EXPERIMENTAL STUDY OF HOLE PRESSURES FOR POLYMER MELTS

A slit die apparatus is used to measure hole pressures for two polymer melts.Hole pressures up to 110kPa are determined and shear rates reach 200 s-1.Viscosity data obtained from the same apparatus agreewell with the values obtained from a cone-and-plate rheometer or a capillary rheometer.The hole pressuresobtained by direct measurements are all positive and increase with increasing shear stress.The values of the firstnormal stress difference obtained from hole pressures according to the Higashitani-Pritchard（HP）theory are ofthe right order of magnitude,but appear to be on the low side when compared with values obtained from a cone-and-plate rheometer or with values obtained via exit pressures.It is believed that the hole pressure is a measureof fluid elasticity,but cannot yield accurate values of the first normal stress difference according to the HP theory.

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE(Ⅰ)MODELING OF THE PERMEATION-SWELLING PROCESS

Water transfer through the organic phase of kerosene containing surfactant Span 80,L113B and certain carrier wasstudied theoretically and experimentally in(W/O)/W liquid surfactant membranes.The process of swelling owing to os-motic pressure can be pictured as solubilization of water in membrane phase caused by surfactant and certain carriers andthen diffusion of it through the membrane between the two aqueous phases due to the gradient of chemical potential.Amathematical model for estimating the permeation-swelling rate has been developed.This mathematical model does notcontain any adjustable parameters and the predicted values agree well with the experimental data of Fujinawa et al.,Xinsheng Ma and Yajun Shi and the authors.Using an apparatus developed for measuring the solubility of water in membrane phase,data for solubilization ofwater in oil caused by some surfactants and carrier were measured.

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE (Ⅰ) ADSORPTION OF SURFACTANT AT THE INTERFACE AND THE SWELLING CAUSED BY EMULSIFICATION

The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C2,can be estimated by Eq.（7）—（9）.The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the"Emulsification" swelling rate,Fse,has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.（26）gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.

CALCULATIONS OF VAPOR-LIQUID EQUILIBRIA FOR HYDROGEN-CONTAINING SYSTEMS WITH MODIFIED PENG-ROBINSON EQUATION OF STATE

Peng-Robinson equation of state was modified to represent vapor-liquid equilibria for hydrogen-containing systems. A new expression of the temperature dependent parameter for the supercritical gas hydrogen, and the binary interaction parameters were introduced to improve the description of VLE for 19 binary systems. Results show that this work is superior to the previous work. Moreover, estimations of PVT behavior, the second virial coefficients for hydrogen, and predictions of the volumetric properties of liquid mixtures and VLE for the ternary systems are in good agreement with the experimental data.

A METHOD OF GREEN'S FUNCTION FOR THE UNSTEADY STATE SOLUTION OF A DISPERSION TYPE TUBULAR REACTOR MODEL WITH AN IMMOBILE ZONE

A general unsteady state solution is obtained by means of Green’s functions for a dispersion-typetubular reactor model with an immobile zone.Arbitrary initial concentration profiles along the reactorfor the flowing zone and the immobile zone are allowed and the feed concentration is time-varying.Firsta self-adjoint operator is defined and then the Green’s function is determined.The solution is finally con-structed from the Green’s function.

GIBBS ENSEMBLE MONTE CARLO SIMULATION OF VAPORLIQUID EQUILIBRIA FOR SIMPLE FLUIDS

The Gibbs ensemble Monte Carlo simulation method has been investigated and used to calculate the vaporliquid equilibria of a real binary mixture, argon-methane. In this simulation, the micro-structural and macroscopic properties, including the distribution function, internal energy, densities and compositions of coexisting vapor and liquid phases as well as the enthalpy of vaporization are obtained. Compared with experimental data and calculated results from equations of state, our simulated phase equilibrium properties are of good accuracy, which demonstrates that this simulation methods is a powerful tool in research on phase equilibria of fluids.

STUDY ON THE SEQUENCE STRUCTURE OF BUTADIENE-STYRENE RUBBER BY ^(13)C-NMR METHOD Ⅲ. QUANTITATIVE CHARACTERIZATION OF SEQUENCE STRUCTURE

The quantitative description of the sequence structure of emulsion-processed SBR and solution-processed SBR (by lithium catalyst)was carried out based on their spectral data Of ^(13)C-NMR.The calculating formulae which could be used to obtain diad concentration from the peak intensifies of carbon spectra, average block length, average number of block, and the microstructure composition of the molecular chain were derived. The quantitative result showed that on the molecular chain styrene unit had the tendency to attach to trans-1,4 butadiene unit. The calculated result of the microstructure was in good agreement with that obtained through IR measurement.

THE EFFECT OF MONOMERS FEEDING METHODS ON EMULSION COPOLYMERIZATION OF VINYLIDENE CHLORIDE AND ACRYLATES

The emulsion copolymerization of vinylidene chloride (VDC) with methyl-methacrylate(MMA) and acrylonitrile (AN) was carried out by batch, seeded batch and semicontinuous pro-cesses,respectively. Significant differences were found in the physical and mechanical propertiesof the latexes and films, depending on the methods of monomer feeding. The results both intheory and experiments demonstrated that the copolymer composition and the length of the VDC sequences in the copolymer could be controlled by the modes of monomer feeding process.

STUDY ON THE SEQUENCE STRUCTURE OF BUTADIENE-STYRENE RUBBER BY ^(13)C-NMR METHOD V.CALCULATION METHOD OF DIAD COMPOSITION

The calculating equations which could be used to obtain diad composition from the peakintensities of carbon spectra were derived. The result of the microstructure calculated from thediad compositions was in good agreement with that obtained through IR or;H-NMR measurement.

DSC STUDY ON THE WATER-ABSORBING MECHANISM OF PLASMA POLYMERIZED N-VINYL-2-PYROROLIDONE

Water existing in water-absorbing plasma polymerized N-vinyl-2-pyrrolidone(PPNVP) include pure bulk water, freezable water and non-freezing, or bound, water. The C-N bond of N, N-disubstituted amides in PPNVP was considered as an active binding site for bound water.

THE PREPARATION CHEMISTRY OF V/MgO CATALYST FOR OXIDATIVE DEHYDROGENATION OF ETHYLBENZENE

The structures and catalytic performances of V_2O_5, Mg_3V_2O_8 and V/MgO catalysts have been correlated by means of XRD, FTIR, TPR and flow micro-reactor tests. The postulation about active site has been made. Based on it, better catalysts have been first prepared via grafting and modification with Sb which are better than that via impregnation.

STUDY ON THE SEQUENCE STRUCTURE OF SBR BY ^(13)C—NMR METHOD Ⅰ. ASSIGNMENT FOR UNSATURAT CARBONS SPECTRA

The sequence structures of emulsion-processed SBR and solution-processed (by lithium catalyst) SBR were investigated by ^(13)C-NMR spectroscopy. Seventeen peaks within unsaturated carbon region were recorded under the adopted experimental conditions. Assignments for these peaks were made by empirical-parameter-evaluation method.

STUDY ON THE SEQUENCE STRUCTURE OF SBR BY ^(13)C-NMR METHOD Ⅱ. PEAK ASSIGNMENT FOR ALIPHATIC CARBONS SPECTRA

The study on ^(13)C-NMR spectra of aliphatic carbon region of emuision-processed and solution-processed (by lithium catalyst) SBR was carried out. The assignments for more than thirty odd peaks observed experimentally were made by using 'corresponding analysis' method, combined with the empirical parameters reported in literature. The peak intensifies were calculated based on BemouUian statistic assumption.

STUDY ON THE CONCENTRATION EFFECTS IN GPC IV A NEW METHOD FOR DETERMINATION OF SECOND VIRIAL COEFFICIENTS FROM THE CONCENTRATION EFFECTS

In this paper a new relation between the second virial coefficients A_2, (?)_w and (dV_(es)/dC)_c→0=K_s was derived from proposed model theory of concentration effects in GPC for mono-and poly-dispersed polymers. Based on this relation a new method for determination of second vifial coefficients from the combination of (dV_(es)/dC)_c→0=K_3, (?)_w and K_H measurements was proposed.The values of A_2 for mono-and poly-dispersed polystyrenes with molecular weight range from 10~4 to 10~6 in good and theta solvents were determined by proposed method. Results show that their values of A_2 are in agreement with those obtained by light scattering.

STUDY ON THE SEQUENCE STRUCTURE OF SBR BY ^(13)C-NMR METHOD Ⅵ MONTE CARLO SIMULATION OF THE SEQUENCE OF SBR

A program of Monte Carlo simulation of binary copolymerization for E-SBR (emulsion polymn. SB rubber) was made according to the terminal model. The simulation results obtained by this program were in good agreement with those experimental ones. A detail microstructure information of E-SBR molecular chain has been provided.

Radiation Induced Variations of Electrical Conductivity in Polyaniline

Induced variations of electrical conductivityσdc of polyaniline byγ-radiation have been studied,σdcdc increases from 2.2 to 2.7S/cm due to radiation with a dose of 30-40Mrad.EPR results show that spin concentration increases at the same rate asσdc.The characteristics ofσdc versus temperature fit to Inσdc∝T^(-1) before irradiation,before irradiation,but to Inσdc∝T^(-1/4) after irradiation.