Influence of ph on morphology and structure during hydrolytic degradation of the segmented gl-b-[gl-co-tmc-co-cl]-b-gl copolymer
Márquez, Yolanda (Universitat Politècnica de Catalunya)
Martínez, Juan Carlos (ALBA Laboratori de Llum de Sincrotró)
Turon, Pau (B. Braun Surgical S.A.)
Franco García, María Lourdes (Universitat Politècnica de Catalunya)
Puiggalí, Jordi (Universitat Politècnica de Catalunya)

Fecha:	2015
Resumen:	Hydrolytic degradation in media having a continuous variation of pH from 2 to 12 was studied for a copolymer having two polyglycolide hard blocks and a middle soft segment constituted by glycolide, trimethylene carbonate, and ?-caprolactone units. The last units were susceptible to cross-linking reactions by ? irradiation that led to an increase of the molecular weight of the sample. Nevertheless, the susceptibility to hydrolytic degradation was enhanced with respect to non-irradiated samples and consequently such samples were selected to analyze the degradation process through weight loss measurements and the evaluation of changes on molecular weight, morphology, and SAXS patterns. Results reflected the different hydrolytic mechanisms that took place in acid and basic media and the different solubilization of the degradation products. Thus, degradation was faster and solubilization higher in the basic media. In this case, fibers showed a high surface erosion and the formation of both longitudinal and deep circumferential cracks that contrasted with the peeling process detected at intermediate pHs (from 6 to 8) and the absence of longitudinal cracks at low pHs. SAXS measurements indicated that degradation was initiated through the hydrolysis of the irregular molecular folds placed on the amorphous interlamellar domains but also affected lamellar crystals at the last stages. Subsequent heating processes performed with degraded samples were fundamental to reveal the changes in microstructure that occurred during degradation and even the initial lamellar arrangement. In particular, the presence of interfibrillar domains and the disposition of lamellar domains at different levels along the fiber axis for a determined cross-section were evidenced.
Ayudas:	Ministerio de Economía y Competitividad MAT2012-36205 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-188
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Publicado en:	Fibers, Vol. 3, Issue 3 (September 2015) , p. 348-372, ISSN 2079-6439

DOI: 10.3390/fib3030348

25 p, 1.6 MB

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