CINDECA   05422
CENTRO DE INVESTIGACION Y DESARROLLO EN CIENCIAS APLICADAS "DR. JORGE J. RONCO"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Kinetics of isothermal degradation studies of nanosilica-polyurethane composites
Autor/es:
J. VEGA-BAUDRIT; P. VÁZQUEZ; J.M. MARTÍN-MARTÍNEZ
Lugar:
Barcelona - España
Reunión:
Jornada; VII Jornadas sobre Adhesivos en EUROCOAT; 2006
Institución organizadora:
EUROCOAT
Resumen:
Polyurethanes
thermoplastics adhesives containing fumed silicas with different degree of
silanization were prepared and characterized using FTIR spectroscopy,
transmission electron microscopy (TEM), differential scanning calorimetry (DSC)
and isothermal thermogravimetric
analysis. The effect of the presence of nanosilicas with different hydrophilic
degree in the thermoplastic polyurethanes was investigated. An analysis of the
isothermal methods to evaluate kinetic parameters of decomposition of solids
from isothermal thermogravimetric data is presented.
In TPU nanocomposites, the segmental
incompatibility on the TPU was increased with the presence of the hydrophilic
nanosilicas. The formation of hydrogen-bonds between soft segments chains from
TPU and the silanol groups on the silica surface was favoured. Therefore, TPU
became well-organized and consequently crystallinity was increased. The results
obtained show that fumed nanosilica improved thermal properties. Kinetic parameters were studied
using degradation standard equation and Arrhenius method. When the temperature of the isothermal analysis
was increased, an increased of the rate constant was obtained. The nanosilica in
TPU decreases the kinetics of decomposition due to the increase of the
interaction between the polyurethane soft segments. The silanol groups on the
silica surface enhance the phase separation and improved the thermal
properties. Finally, the
fumed nanosilica in TPU-nanocomposites changed the thermal degradation
mechanism.