A solid-state 13 C NMR analysis of ambers
2000; Elsevier BV; Volume: 41; Issue: 2 Linguagem: Inglês
10.1016/s0032-3861(99)00195-0
ISSN1873-2291
AutoresAntonio Martínez‐Richa, Ricardo Vera‐Graziano, A.M. Morales Rivera, Pedro Joseph‐Nathan,
Tópico(s)Photorefractive and Nonlinear Optics
ResumoColombian copalite samples (found at 73°5′W 6°19′N in the Cimitarra quadrangle), and commercial amber samples from Chiapas (Mexico), Dominican Republic and Poland (Baltic) were studied using solid-state 13C CP-MAS Nuclear Magnetic Resonance (NMR). NMR spectra for Colombian amber are shown and compared to those reported for the resin from the genus of the African species Hymenaea verrucosa and other Hymenaea trees, for which a close resemblance is observed. NMR spectral features of the other studied ambers are also discussed. A physical aging experiment was performed on a Colombian sample at 65°C. Differences in the solid-state NMR and IR spectra are explained in terms of changes in chemical cross-linking, isomerization and morphology.
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