13C spin-lattice relaxation times and NOE factors were measured as a function of temperature in two magnetic fields for the protonated backbone carbons of poly(/~-hydroxybutyrate-co-/~-hydroxyvalerate) (PHB/V) copolymer in chloroform-d. Analysis of the relaxation data by employing the Dejean-Laupr&re- Monnerie model reveals the following motional characteristics of the copolymer chain: (1) the local dynamics of a comonomer unit, e.g. HB, is independent of the presence of a nearby HV unit and vice versa; (2) different local dynamics prevail not only between the various comonomers, but also within a given comonomer unit in the random copolymer chain; (3) chain segmental motion of the copolymer described by co-operative conformational transitions is similar to that observed for the PHB homopolymer in a previous study
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Segmental motion of poly (p-hyd roxybutyrateco-/ -hydroxyvalerate) in chloroform solution studied by 13C n.m.r, relaxation / Photis Dais and Maria Elena Nedea and R. H. Marchessault // Polymer. – 1992. – Vol 33. – P. 4288-4291.