ELISABETH CARVALHO L. CARDOSO

ELISABETH CARVALHO L. CARDOSO

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Study of flexible films prepared from PLA/PBAT blend and PLA E-beam irradiated as compatibilizing agent
2017 - CARDOSO, ELIZABETH C.L.; OLIVEIRA, RENE R.; MACHADO, GLAUSON A.F.; MOURA, ESPERIDIANA A.B.
Plastics global annual production exceeds 250 million tons and more than 40% of the total plastic production is used as packaging materials. In recent years polymeric materials derived from biomass have received great attention due to scarce petroleum resources and environmental concerns. PLA is one of the most extensively studied bio-based and bio-compostable aliphatic polyesters; nevertheless, high brittleness and low toughness limits its application. Blending PLA with PBAT (Poly(butylene adipate-co-terephthalate)), an aliphatic-aromatic copolyester, was the solution found due to its high toughness and biodegradability. Differences between PLA and PBAT solubility parameter values lead to the formation of immiscible blends as well as reduction in their mechanical performance besides a poor morphology; so, 5% of pre-irradiated PLA and a previous compatibilized PLA/PBAT (EcovioTM) were added to PLA/PBAT blends in order to improve miscibility phases. Investigations were accomplished on phase morphology (SEM), mechanical properties, thermal behavior and X-ray diffractions (XRD).
Effects of bio-CaCO3 nanoparticles and graphene nanosheets on properties of PBAT/PLA flexible films treated by ionizing radiation
2016 - REIS, PEDRO R.S.; CARDOSO, ELIZABETH C.L.; LOURENÇO, FELIPE R.; ORTIZ, ANGEL V.; RANGARI, VIJAY K.; MOURA, ESPERIDIANA A.B.
Study of flexible films prepared from PBAT/PLA blends reinforced with bio-CaCO3
2016 - CARDOSO, ELIZABETH C.L.; BUENO, NELSON R.; OLIVEIRA, RENE R.; MOURA, ESPERIDIANA A.B.
Plastics global annual production exceeds 250 million tons and more than 40 % of the total plastic production is used as packaging materials. The most widely used materials include polyethylene (PE) and polypropylene (PP), among others. However, petrochemical-based conventional packaging materials are non-biodegradable and cause serious environmental problems. Poly (lactic acid) (PLA), a linear aliphatic polymer is known as a biodegradable thermoplastic polymer with widely potential applications. However, its high brittleness and low toughness limits its application; blending PLA with PBAT (Poly (butylene adipate-co-terepthalate), an aliphatic-aromatic copolyester, was the solution found due to its high toughness and biodegradability. Nevertheless, differences between PLA and PBAT solubility parameter values lead to the formation of immiscible blends as well as reduction in their mechanical performance. CaCO3 from avian eggshells, when added in PLA / PBAT composites imparts optimization of mechanicals properties due to its characteristic as reinforcing filler. This study aims to evaluate the effects of PLA addition in PBAT/PLA blends especially concerned to mechanical and thermal properties of PLA / PBAT / CaCO3 flexible films. Composites were prepared by melt processing, using a twin-screw extruder (L/D - 25). Before blown film processing, the composites were cooled down for a better dimensional stability, pelletized and dried at 60 ± 2 ºC for 24 h. The mechanical and thermal properties of obtained films were investigated by tensile tests, DSC and TG / DTG. In addition, the morphology of blends and composites were also evaluated by XRD and SEM analyses. The results showed important increase in crystallinity and tensile strength at break of flexible films without severe loss in elongation percentage, due to CaCO3 additional in PBAT / PLA blend with higher PLA contents.
Development of bio-based foams prepared from PBAT/PLA reinforced with biio-calcium carbonate compatibilized by electron beam radiation
2016 - CARDOSO, ELIZABETH C.L.; SEIXAS, MARCUS V.S.; WIEBECK, HELIO; OLIVEIRA, RENE R.; MACHADO, GLAUSON A.F.; MOURA, ESPERIDIANA A.B.