| dc.description.abstract | Polyethylene terephthalate (PET) is a very important polymer, but this kind of synthetic
polymer is resistant to biological degradation. For this reason there is an urgent need to
develop renewable source based biopolymers able to degrade via a natural composting
process. An interesting biodegradable polymer is poly(lactide acid) (PLA), which made
primarily from renewable agricultural resources. Extrusion is widely used for processing
thermoplastic polymer, and studies indicate that, under the high-shear and high-temperature
conditions, polymers can undergo a variety of changes at the intra and intermolecular level.
Therefore an extrusion process is a very attractive approach, for obtained polymeric blends.
In this work, poly(ethylene terephthalate) (PET)-poly(lactide acid) (PLA) blends at different
PLA contents (1, 2.5, 5 and 7.5 wt-%), are proposed. PET, PLA and their blends are obtained
by extrusion method and characterized using DSC, XRD, SEM, AFM and mechanical tests.
The glass transition temperatures (Tg) are ranging from TgPET (74.91 °C) to TgPLA (61.54 °C),
as the PLA content increase: 73.12 °C, 69.04 °C, 65.91 °C and 62.11 °C, for 1, 2.5, 5 and 7.5
wt-%, respectively. From XRD, it can be observed that all the blends are missing the
crystallite signals from PET and PLA, and only the amorphous character is detected. Spherical
form agglomerates, immersed in an amorphous matrix, are detected by SEM; any different
phases are not distinguishable, then, a selective solvent was used to dissolve PLA and
determine the sites that this polymer occupies in the blend. The differences were observed by
SEM and also by AFM. The 2.5 wt-% blend shows a high tensile strength (76-79%) and, was
observed by the morphology of the fracture behavior of polymer is ductile. | |
