Thermomechanical behavior, light and X-ray scattering of polylactic acid
Por:
Reyes-Mayer, Adriana, Romo-Uribe, Angel
Publicada:
1 ago 2014
Resumen:
This research focuses on the thermal properties, microstructure and
mechanical behavior of extruded films of biodegradable polylactic acid
(PLA) and compares these properties with those from polyethylene, high
density and linear low density. Thermal properties showed poorer thermal
stability of PLA (some 100 degrees C lower than the polyolefins), and
poorer ability for PLA to crystallize, exhibiting a pronounced cold
crystallization exothermic peak, not present in the extruded
polyolefins. Poor crystallization in PLA films was corroborated by
wide-angle and small-angle X-ray scattering, and hot-stage optical
microscopy. Uniaxial deformation showed that the mechanical properties
of PLA film along and orthogonal to the extrusion direction (determined
under uniaxial testing at room temperature) are significantly larger
than the polyolefins, by a factor of 2-6. Moreover, the mechanical
properties along and orthogonal to the extrusion direction revealed
significant anisotropic mechanical properties of PLA. Furthermore, the
mechanical modulus of PLA was a decreasing function of strain rate thus
suggesting a strain rate softening behavior.
Filiaciones:
Reyes-Mayer, Adriana:
Univ Nacl Autonoma Mexico, Lab Nanopolimero & Coloides, Inst Ciencias Fis, Cuernavaca 62191, Morelos, Mexico
Romo-Uribe, Angel:
Univ Nacl Autonoma Mexico, Lab Nanopolimero & Coloides, Inst Ciencias Fis, Cuernavaca 62191, Morelos, Mexico
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