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International Journal of Biomaterials
Volume 2017, Article ID 6435076, 8 pages
https://doi.org/10.1155/2017/6435076
Research Article

Influence of Processing Conditions on the Mechanical Behavior and Morphology of Injection Molded Poly(lactic-co-glycolic acid) 85:15

1Biomechanical Engineering Laboratory (LEBm), University Hospital (HU), Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil
2Laboratory of Innovation on Additive Manufacturing and Molding (NIMMA), Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil
3GRANTE, Department of Mechanical Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC, Brazil

Correspondence should be addressed to Liliane Pimenta de Melo; moc.liamg@gne.enailil

Received 3 May 2017; Accepted 19 June 2017; Published 7 August 2017

Academic Editor: Jie Deng

Copyright © 2017 Liliane Pimenta de Melo et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Two groups of PLGA specimens with different geometries (notched and unnotched) were injection molded under two melting temperatures and flow rates. The mechanical properties, morphology at the fracture surface, and residual stresses were evaluated for both processing conditions. The morphology of the fractured surfaces for both specimens showed brittle and smooth fracture features for the majority of the specimens. Fracture images of the notched specimens suggest that the surface failure mechanisms are different from the core failure. Polarized light techniques indicated birefringence in all specimens, especially those molded with lower temperature, which suggests residual stress due to rapid solidification. DSC analysis confirmed the existence of residual stress in all PLGA specimens. The specimens molded using the lower injection temperature and the low flow rate presented lower loss tangent values according to the DMA and higher residual stress as shown by DSC, and the photoelastic analysis showed extensive birefringence.