Further Test of the Two-Parameter Theory of Dilute Polymer Solutions: Poly(p-bromostyrene)

Abstract

ABSTRACT:Light-scattering and intrinsic-viscosity data are presented for fractions of po1y(p-bromostyrene) in monochlorobenzene and dioxane at 30°C, and in benzene at temperatures ranging from 25 to 50°C. The theta temperature for this polymer in benzene is 26.3°C. With the data for the statistical-radius expansion factor as and the interpenetration function 1f! appearing in the second virial coefficient, the agreement between theory and experiment is examined with respect to the same two criteria as those employed in the previous study on poly(p-methylstyrene). The Yamakawa-Tanaka theory of as and also the modified Flory theory are again found to satisfy both criteria. The data also reproduce the relationship between the cubed viscosity-radius expansion factor and the excluded-volume parameter z if z is estimated using the Yamakawa-Tanaka equation for as. Specifically, the first-order perturbation theory of recently developed by Yamakawa and Tanaka compares well with the data near the theta temperature. The recent critical comments by lsihara and Nagasawa are also replied to.KEY WORDS Two-Parameter Theory/Excluded-Volume Effect/MeanSquare Radius/Second Virial Coefficient/Intrinsic Viscosity/Expansion Factor/Light Scattering/Poly(p-bromostyrene)/ Recently, extensive experimental tests of the two-parameter theory of dilute polymer solutions have been made by four research groups. The foremost of these is the work of Berry 1 who carried out light-scattering and viscosity measurements on solutions of polystyrene. Subsequently similar studies were made on polychloroprene by Fujita, et a/., 2 ' 3 on poly(p-methylstyrene) by Yamakawa, eta/., 4 and on poly(a-methylstyrene) by Nagasawa, et al. 6 ' 6 The raw data of the first three groups are consistent with one another, but those of Nagasawa, et al., are somewhat different from others in behavior. In addition, no definite conclusion has been reached.In this work, our primary attention is directed to the behavior of the mean-square radius <S 2 ) and intrinsic viscosity [r;] of a polymer chain, or the statistical-radius expansion factor as and viscosity-radius expansion factor as defined bywhere <S

Solvent and temperature influences on polystyrene unperturbed dimensions

“…For polystyrene in cyclohexane the transition is purported102,103 to lead to a Kq value at 40 °C, which is lower than that found under conditions. Suffice it to state that these findings103-105 are not supported by valid theory2 nor by extensive data36, 41,44,53,54,[57][58][59]61,63,65,[104][105][106][107][108][109][110][111][112][113] for various solvent-polymer systems on the temperature dependence of intrinsic viscosity, second virial coefficient, chain dimensions, and diffusion coefficients near the temperature.…”

Excluded volume effects and binary cluster integrals in dilute polymer solutions

“…81. In this paper, we use light-scattering and viscosity data obtained recently by our group82 for monodisperse polystyrenes (prepared anionically in tetrahydrofuran) to test the theory following our procedure.…”

Effect of Solvent Quality and Chain Confinement on the Kinetics of Polystyrene Bromination

“…Over the past few decades numerous researchers reported on the formation and physicochemical properties of poly(4-bromostyrene) (PBrS) and its copolymers. These studies have been motivated by excellent flame-retarding properties − and unique phase behavior of PBrS. − A variety of synthetic methodologies for obtaining homopolymers and copolymers of bromostyrene have been described, including free radical, , cationic, , anionic, and controlled radical polymerization . In addition, the synthesis of random copolymers, poly(styrene- co -4-bromostyrene) (PBr x S), comprising styrene and 4-bromostyrene units, has been reported that utilized bromination reaction performed on parent polystyrene (PS) coils. − The latter reaction has several advantages.…”