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para ‐Substituted Poly(styrene peroxide)s: Synthesis, Characterization, Thermal Reactivities, and Chain Dynamics Studies in Solution
Author(s) -
De Priyadarsi,
Sathyanarayana D. N.
Publication year - 2002
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20020101)203:2<420::aid-macp420>3.0.co;2-z
Subject(s) - polymer chemistry , styrene , copolymer , chemistry , activation energy , peroxide , glass transition , differential scanning calorimetry , reactivity (psychology) , polymer , thermogravimetry , organic chemistry , thermodynamics , inorganic chemistry , physics , medicine , alternative medicine , pathology
Abstract The synthesis and spectroscopic characterization of three polymeric peroxides of styrene monomers with substituents in the para position are discussed. NMR spectroscopy revealed the alternating copolymer structure with labile peroxy bonds (—O—O—) in their main chain. The thermal reactivity of the polymers was studied by differential scanning calorimetry and thermogravimetry. The measured heat of degradation of these polymers is nearly the same as that of poly(styrene peroxide). The mechanism of the primary exothermic degradation has been substantiated by thermochemical calculations. The chain dynamics studies of these polyperoxides in terms of 13 C spin‐lattice relaxation time ( T 1 ) have been carried out to understand their main chain flexibility. The temperature dependence of correlation time has been utilized for the determination of the activation energy for the overall segmental motion and internal group rotation. Their flexibility in terms of glass transition temperature ( T g ) have been examined. The flexibility trend observed in solution parallels that in the bulk.