INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Mechanical performance under severe stress conditions of plasticized polylactic acid/poly(3-hydroxybutyrate) blends.
Autor/es:
L. A. FASCE; V. P. CYRAS; PETTARIN, VALERIA; L. B. MANFREDI; IGLESIAS MONTES, MAGDALENA L.; D'AMICO DAVID ALBERTO
Lugar:
Sevilla
Reunión:
Simposio; Fifth International Symposium Frontiers in Polymer Science; 2017
Resumen:
The development of new biobased and biodegradable packaging materials is constantly growing. Polylactide acid (PLA) and poly (3-hydroxybutyrate) (PHB) are environmentally friendly polyesters with highly promising perspectives for short-life applications. However, the inherent brittleness of PLA and PHB leads to rigid films which need to be modified to enhance their flexibility. One common practice is plasticizer addition.In a previous work, blends with different ratio PLA (Nature Works)/PHB (PHB Industrial) (70/30 and 60/40), plasticized with 10, 15 and 20 wt% of glyceryl tributyrate (TB) (Fluka), were obtained in a Haake mixer (185ºC and 50 rpm) and characterized. The blends containing 15 wt% of TB presented the best mechanical properties regarding uniaxial tensile tests, showing good balance between stiffness and deformation capacity. Nonetheless, when the stress conditions are more severe the materials? performance could change from ductile to fragile. Therefore, the present work aims to evaluate the fracture and impact performance of the selected blends. Fracture tests were carried out on mode I double edge-notched tensile specimens (DENT) at constant deformation rate (1 or 10 mm/min). Different Fracture Mechanics approaches were applied depending on the materials´ fracture behaviour. The Essential Work of Fracture methodology was adopted for blends that exhibited ductile fracture behaviour, J-Integral at instability (Jc) for ductile instability performance, and the stress intensity factor (KIc) for films that presented brittle behaviour. Dart impact experiments were conducted on a Fractovis Ceast falling weight type machine at room temperature at 0.5 m/s. Thickness related energy (U/t) and disc maximum strength (σd) were determined.