Temperature Influence on the Heterocontact Interactions in Styrene-Acrylonitrile Copolymers

392-39

Dilute Solution Properties of Styrene-Acrylonitrile Random Copolymers: Part III-Temperature Variation of Limiting Viscosity Number

389-39

Permeability properties of polyelectrolyte complexes from carboxymethyl-cellulose and poly(2-vinyl- N-methylpyridinium iodide)

334-337Polyelectrolyte complexes between carboxymethylcellulose and poly(2-vinyl-N-methylpyridinium iodide) have been studied. The polycation of two different degrees of substitution was used to make complex precipitates that differ in the stoichiometry. The diffusive permeability of KCl and urea through the solution cast membranes of these complex precipitates has been studied. The polyelectrolyte complex membrane containing the polycation of higher degree of substitution has been found to possess good membrane properties

Electromembrane from polyelectrolyte complex of polyaniline and carboxymethylcellulose

338-341A Composite membrane of polyaniline and carboxymethylcellulose has been prepared. The polyaniline in the membrane exists in the conducting state even at pH as high as 6.5, due to the Donnan effect. At high ionic strength, the polyaniline changes to the nonconducting state, but the rate is slow enough to make application of the membrane at high pH possible. It has been shown that the degree of protonation of polyaniline changes the permeability of the membrane. Further, we have proposed that for composites like polyaniline-carboxymethylcellulose, the permeability can be changed by changing the oxidation state of the conducting polymer, thereby changing the crosslinking between the polymer components

Permeability properties of polyelectrolyte complexes from carboxymethyl-cellulose and poly(2-vinyl- N-methylpyridinium iodide)

334-337Polyelectrolyte complexes between carboxymethylcellulose and poly(2-vinyl-N-methylpyridinium iodide) have been studied. The polycation of two different degrees of substitution was used to make complex precipitates that differ in the stoichiometry. The diffusive permeability of KCl and urea through the solution cast membranes of these complex precipitates has been studied. The polyelectrolyte complex membrane containing the polycation of higher degree of substitution has been found to possess good membrane properties

Use of a compensation parameter in the Thermal Decomposition of Copolymers

During the past 25 years, thermal techniques have been widely used to study the kinetics of solid state decomposition reactions. In principle, one should find prodigious data on homopolymers, to facilitate the interpretation of the thermal decomposition behaviour of copolymers. During recent studies on poly(styrene-co-methyl methacrylate), however, it was found that the available data on polystyrene and poly(methy1 methacrylate)was too inconsistent to be used with any level of confidence. Isothermal and nonisothermal experiments are found to yield differing kinetic parameters. Procedural factors, such as the heating rate, sample size,pretreatment of the sample, container shape and atmosphere, are implicated in the widely differing calculated parameters; the range of decomposition studied and the particular form of the equation used for data reduction also have an effect

Electromembrane From Polyelectrolyte Complex of polyaniline and carboxymethylcellulose

338-341A Composite membrane of polyaniline and carboxymethylcellulose has been prepared. The polyaniline in the membrane exists in the conducting state even at pH as high as 6.5, due to the Donnan effect. At high ionic strength, the polyaniline changes to the nonconducting state, but the rate is slow enough to make application of the membrane at high pH possible. It has been shown that the degree of protonation of polyaniline changes the permeability of the membrane. Further, we have proposed that for composites like polyaniline-carboxymethylcellulose, the permeability can be changed by changing the oxidation state of the conducting polymer, thereby changing the crosslinking between the polymer components

Dilute solution properties of methyl methacrylate—acrylonitrile copolymer (MA2)

This article deals with studies of the dilute solution properties of methyl methacrylate-acrylonitrile (MMA-AN) copolymer of 0.415 mole fraction (mf) of acrylonitrile composition. Mark—Houwink parameters for this copolymer have been evaluated in acetonitrile (MeCN), 2-butanone (MEK), dimethyl formamide (DMF), and γ-butyrolactone (γ-BL). The Mark-Houwink exponent a in all four solvents at all temperatures is larger than the corresponding values of the parent homopolymers. The solvent power is in the order of DMF < γ–BL < MEK < MeCN; [η] decreases with an increase in temperature, which is behavior characteristic of polymers in good solvent. The unperturbed dimensions (K0) values, obtained by the Stockmayer–Fixman method, are lower than those for the parent homopolymers and depend on solvent as well as temperature. The solute—solvent interaction parameter X1 values are close to 0.5; X1 is independent of temperature. The excess interaction parameter XABvalues are negative. The results for this copolymer system in regard to low second virial coefficient A2, large X1, and high a values suggest that the large extension of these copolymer chains is due to the unusual short-range interactions