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Dilute solution properties of styrene–acrylonitrile and styrene–methyl methacrylate copolymers. II. Short‐range and long‐range interactions from intrinsic viscosity data

1976; Wiley; Volume: 14; Issue: 4 Linguagem: Inglês

10.1002/pol.1976.180140415

1542-9385

C. Rami Reddy, V. Kalpagam,

Polymer crystallization and properties

Abstract Experimental data on styrene–acrylonitrile (St–AN), and styrene–methyl methacrylate (St–MMA) copolymers reported in Part I of this series are tested by “two‐parameter” theoretical relations. The Fox–Flory (F–F) parameter K is estimated using the F–F, Stockmayer–Fixman (S–F), and Inagaki–Ptitsyn (I–P) equations. In general, the K values obtained by the F–F equation are low for the three St–AN copolymer samples in the systems studied while the values obtained from S–F and I–P equations agree within the limits of experimental error. Values of K obtained from Kurata–Stockmayer (K–S) equation for sample SA 1 agree with values obtained by the S–F and I–P equations. The specific solvent effect on the K values is discussed. Values of the unperturbed dimension r̄0 2 /M̄ w , calculated from the K values estimated from the S–F equation and from the homopolymer data are compared. Except in one case, the calculated r̄0 2 /M̄ w values from homopolymer data are low in comparison with the values obtained from experimental data, which shows that the presence of the repulsive interactions between unlike monomer units brings about an expansion of copolymer molecule. The effect of composition on the steric factor σ values is discussed. The long‐range interaction parameter B , the excess interaction parameters Δ B AB , and χ AB are calculated. The effects of composition and solvent on these parameters are discussed.