Styrene‐methyl acrylate copolymers and acrylate homopolymers in solution

Abstract

Molecular weight determinations by light scattering and osmometry and intrinsic viscosity measurements were made in various solvents on fractions of styrene–methyl acrylate copolymers with different compositions and on acrylate homopolymers prepared by free‐radical reaction. Relations between intrinsic viscosity [η] and molecular weight M thus established are compared with those reported by other authors. 2‐Methylcyclohexanol was found to be a theta solvent for the copolymers and both parent homopolymers, and isoamyl acetate was a theta solvent for poly(methyl acrylate). From theta point viscosity data obtained with these solvents, unperturbed chain dimensions were estimated. The results are compared with the unperturbed dimensions estimated from the [η]–M relations obtained in good solvents. On the basis of the experimental data it was found that the unperturbed dimension depends linearly on the copolymer composition, in contrast to the case of styrene–methyl methacrylate copolymers. Composition dependences of the theta temperature and of the parameter describing the long‐range interactions between nonadjacent segments in polymer chains were investigated. The result implies that long‐range interactions between monomeric units never disappear even when those between the same monomeric units vanish. The Huggins constant for copolymer is discussed in terms of the excluded volume variable.

Liquid-liquid equilibria and theta temperatures in binary solvent-copolymer solutions from a perturbed hard-sphere-chain equation of state

“…When a pair of copolymer molecules interacts with each other, eq. (5) assumes that the contact frequency between a pair of particular segments depends only on the copolymer composition; this assumption is reasonable only for truly random copolymers.…”

“…For this system, eqs. ( 4 ) and (5) are As discussed in ref. 19, in polymer solutions, overestimation of the equation-of-state effect is caused by the overestimated contribution from G2, in the perturbation term.…”

Aqueous polymerization of methyl acrylate initiated by ceric ion-reducing agent systems in nitric acid medium

“…The variation of the molecular weights of the polymers formed at different % conversions was determined by measuring the intrinsic viscosities of the polymers obtained at different % conversions and computing from the viscosity-molecular weight relationship from the literature [8] (Table 1).…”

Dilute Solution Properties of Random Acrylonitrile/ Methyl Acrylate Copolymer

“…Using the MHS equation for Flory's theta solvent and method 2E, we estimated A and the related parameters from literature data for PAN in DMP and for PMA in isoamyl acetate. 12 Figure 12, which illustrates the relation between A (or a or C00 ) and AN content for PAN, the ANjMA copolymer and PMA, indicates that the AN/MA copolymer containing 8 wt% (i.e., 5 mol%) MA is more flexible than PAN in DMF.…”