Stress-induced bimodal ordering in POSS/PCL biodegradable shape memory nanocomposites
Por:
Alvarado-Tenorio B., Romo-Uribe A., Mather P.T.
Publicada:
1 ene 2012
Resumen:
Simultaneous wide- and small- angle X-ray scattering (WAXS-SAXS) has revealed a stress-induced bimodal orientation of POSS crystals and PCL chains, both in a constrained POSS/PCL crosslinked network architecture with shape memory properties. POSS/PCL nanocomposites with molecular weight of 2,600 g/mol exhibiting shape memory behavior were synthesized and variation of crosslinker molar ratio was used to obtain POSS/PCL networks with different crosslink density (Alvarado-Tenorio et al., Macromolecules, 44, 5682, 2011). In that study it was shown that there are POSS crystals embedded in an amorphous PCL matrix, and the POSS crystals were ordered in a cubic nanostructure. In this work, it will be shown that elongation at room temperature of all the networks yielded a double-induced orientation (90° and 180°) of the POSS crystals, as indicated by the 101 reflection. Moreover, it was also detected stretched-induced crystallization of the otherwise amorphous PCL chains. Furthermore, SAXS data showed long periods in the meridional and equatorial orientations of 630 Å, 90 Å and 45 Å corresponding to a lamellar nanostructure of PCL chains. The induced bimodal orientation of the POSS-PCL molecular network will be correlated with its shape memory properties. © 2012 Materials Research Society.
Filiaciones:
Alvarado-Tenorio B.:
Lab. de Nanopolímeros y Coloides, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca Mor. 62210, Mexico
Syracuse Biomaterials Institute, Syracuse University, Syracuse, NY 13244-1240, United States
Romo-Uribe A.:
Lab. de Nanopolímeros y Coloides, Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca Mor. 62210, Mexico
Mather P.T.:
Syracuse Biomaterials Institute, Syracuse University, Syracuse, NY 13244-1240, United States
|