INVESTIGADORES
MOSIEWICKI mirna Alejandra
artículos
Título:
Polyaniline Modified Cellulose Nanofibrils as Reinforcement of a Smart Polyurethane
Autor/es:
M. L. AUAD; T. RICHARDSON; W. J. ORTS; E. S. MEDEIROS; L. H. C. MATTOSO; M. A. MOSIEWICKI; N. E. MARCOVICH; M. I. ARANGUEN
Revista:
POLYMER INTERNATIONAL
Editorial:
JOHN WILEY & SONS LTD
Referencias:
Año: 2011 vol. 60 p. 743 - 750
ISSN:
0959-8103
Resumen:
Segmented polyurethanes exhibiting shape memory properties were modified by the addition of polyaniline (PANI)-coated
cellulose nanofibrils (CNFs). The two-phase structure of the polymer is responsible for the materials ability to remember
and autonomously recover its original shape after being deformed in response to an external thermal stimulus. PANI was
grown on the surface of the CNFs via in situ polymerization.Modified nanocrystals were added to the segmented polyurethane
in concentrations ranging from 0 to 15 wt%. The changes in the material properties associated with the percolation of the
coated fibrils appear at higher concentrations than previously observed for non-modified CNFs, which suggests that fibril
agglomeration is occurring due to the PANI coating. The shape memory behavior of the composites is maintained at about
the same level as that of the unfilled polyurethane only up to 4 wt% of fibrils. At higher concentrations, the rigidity of the
nanofibrils as well as their interaction with the hard-segment phase and the increasing difficulty of dispersing them in the
polymer collaborate to produce early breakage of the specimens when stretched at temperatures above the melting point of
the soft segments.