INVESTIGADORES
ALVAREZ Vera Alejandra
artículos
Título:
Overall Crystallization Behavior of PolypropyleneClay Nanocomposites; Effect of Clay Content and Polymer/Clay Compatibility on the Bulk Crystallization and Spherulitic Growth
Autor/es:
CLAUDIO JAVIER PÉREZ; VERA ALVAREZ
Revista:
JOURNAL OF APPLIED POLYMER SCIENCE
Editorial:
JOHN WILEY & SONS INC
Referencias:
Año: 2009 vol. 114 p. 3248 - 3260
ISSN:
0021-8995
Resumen:
The effect of clay nanoparticles on the overall
crystallization (isothermal crystallization, spherulitic
growth, and nonisothermal crystallization) behavior of polypropylene
(PP) was studied by means of differential scanning
calorimetry and polarized light optical microscopy. In
addition, the changes produced by the compatibility
between the filler and the matrix were analyzed by using
more hydrophobic clays or incorporating PP grafted with
maleic anhydride (PP-g-MA). Different models were used to
predict the relative degree of crystallinity and several parameters
were analyzed. A clear nucleating effect of clay nanoparticles
was found on the experimental behavior (induction
time, half-crystallization time, and overall crystallization
time) and also deducted from the models parameters
(Avrami exponent, rate constant, nucleation activity, activation
energy). The effect was also related with the matrix/clay
compatibility. In addition, the polarized light optical microscopy
showed that the number of spherulites increased and
their size decreased when clay was incorporated, which is
also an indication of the heterogeneous nucleating behavior
of such particles. We also noted faster spherulitic growth
and increasing Kg (the model parameter).