000			01855nam a2200241Ia 4500
003			MX-MdCICY
005			20250625153852.0
040			_cCICY
090			_aB-12380
245	1	0	_aA thermal analytical study of some modern and fossil resins from New Zealand
490	0		_vThermochimica Acta, 326(1-2), p.143-149, 1999
520	3		_aDifferential and thermogravimetric analyses of New Zealand modern, Pleistocene (<30 000 years)and Tertiary (>40 000 000 years)Agathis resins show a progressive change in their combustion pro®les with increasing age. Differences between modern resins and Pleistocene Kauri gums are minimal. Both exhibit thermal events in the low-temperature range, commencing near 1008C and extending to 3008C, that re¯ect the relative abundance of more reactive, undersaturated, carboxyl-rich, unpolymerized components in the younger samples. Diagenetic changes accompanying thermal maturation reveal a reduction in intensity of thermal responses below 2008C and a progression in the temperature of the major thermal combustion event, from 350±4508C in the younger resins, to 450±5808C in the 40 000 000-year-old copals. These variations in thermal behavior accord with a reduction in undersaturated bonds and functionalized groups, and an increase in the proportion of aromatized groups that characterize resin aging. Used judiciously, thermal behavior may indicate maturation histories and resin associations.
650	1	4	_aAGATHIS
650	1	4	_aNEW ZEALAND
650	1	4	_aRESIN
650	1	4	_aCOPAL
650	1	4	_aTHERMAL ANALYSIS
700	1	2	_aRodgers, K.A.
700	1	2	_aCurrie, S.
856	4	0	_uhttps://drive.google.com/file/d/1dVIBNsKxA8D1clBoLycS-u7m642LwU7E/view?usp=drivesdk _zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
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