On the Absence of Cyclic Structures in Branched Polystyrenes Synthesized by Living Three-Dimensional Radical Polymerization in the Medium of a Deteriorating Thermodynamic Quality Solvent

• Published in: Polymer science. Series B Vol. 65; no. 3; pp. 284 - 293
• Main Authors: Kurochkin, S. A., Makhonina, L. I., Perepelitsina, E. O., Bubnova, M. L., Berezin, M. P., Grachev, V. P.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-06-2023; Springer Nature B.V
• Subjects: Chemistry; Chemistry and Materials Science; Copolymerization; Divinylbenzene; Glass transition temperature; Macromolecules; NMR spectroscopy; Polymer Sciences; Polymerization; Polymers; Polystyrene resins; Size exclusion chromatography; Solvents; Synthesis; Tetrahydrofuran; Thermodynamics
• ISSN: 1560-0904; 1555-6123
• DOI: 10.1134/S1560090423700938

Branched polystyrenes are synthesized by the radical copolymerization of styrene and divinylbenzene with reversible inhibition (in the presence of 2,2,6,6-tetramethylpiperidine-1-oxyl) under deteriorating thermodynamic quality of the solvent. The resulting polymers are studied by size-exclusion chromatography combined with static light scattering, ozonolysis, NMR spectroscopy, and differential scanning calorimetry. The branched polymers synthesized by living radical polymerization are characterized by lower intrinsic viscosity values than their linear analogs. Kuhn–Mark–Houwink parameters for these polymers in a tetrahydrofuran solution (
а
= 0.29) confirm the nonlinear architecture of macromolecules and a high content of pendant double bonds comparable in the order of magnitude with their theoretical content in the absence of the cyclization reaction indicate their branched structure. The glass transition temperature of the branched polystyrenes is 20–35°С lower than the glass transition temperature of the linear polystyrene.