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Memorias de investigación
Research Publications in journals:
Water-induced structural changes in poly(lactic acid) and PLLA-clay nanocomposites
Year:2016
Research Areas
  • Macromolecules and polymers
Information
Abstract
The influence of nanoclays on the structural changes of hydrated poly( L -lactic acid) (PLLA) was investigated at two temperatures, above and below its Tg. Samples of a commercial PLLA and nanocomposites with 2 wt% of an organically modified montmorillonite and an unmodified halloysite were kept in a phosphate buffered solution for different times at 37 and 58 ? C and then characterized. The crystallinity degrees and the nature of the crystalline structures developed were determined by differential scanning calorimetry, X-Ray Diffraction and Fourier Transform infrared spectroscopy. While in the cold crystallization of PLLA in dry conditions the a form is obtained only above 100 ºC, different mixtures of a and a 0 forms were obtained in water at 58 ºC, depending on the clay used. The hydrolytic degradation of PLLA played a main role in the structural transformations found at long immersion times, since the short chains formed allowed greater crystallinity degrees and leaded to more perfect crystals. PLLA structure is changed by clays because of its ability as nucleating agents but also due to its effect on the hydrolytic degradation. The unmodified tubular halloysite inhibited degradation, so that lower degrees of crystallinity were obtained in the halloysite based nanocomposite. On the other hand, the modified montmorillonite acted as catalyst of degradation, which explained the appearance of crystalline structures in the nanocomposite with montmorillonite after 84 days of immersion at 37 ºC.
International
Si
JCR
Si
Title
Polymer
ISBN
0032-3861
Impact factor JCR
3,586
Impact info
Volume
107
10.1016/j.polymer.2016.11.031
Journal number
From page
211
To page
222
Month
SIN MES
Ranking
Participants
  • Autor: Freddys Beltran Gonzalez (UPM)
  • Autor: Maria Ulagares De la Orden Hernandez (UPM)
  • Autor: Vicente Lorenzo Esteban (UPM)
  • Autor: Joaquin Maria Martinez Urreaga (UPM)
Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Polímeros, Caracterización y Aplicaciones
  • Departamento: Ingeniería Química Industrial y del Medio Ambiente
  • Departamento: Física Aplicada e Ingeniería de Materiales
S2i 2020 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)