Characterization of PLA-limonene blends for food packaging applications

Polymers derived from renewable resources are now considered as promising alternatives to traditional petro-polymers as they mitigate current environmental concerns (raw renewable materials/biodegradability). D-limonene can be found in a variety of citrus, indeed is the main component of citrus oils and one of most important contributors to citrus flavor. The incorporation of limonene in PLA matrix was evaluated and quantified by Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS). Transparent films were obtained after the addition of the natural compound. Mechanical properties were evaluated by tensile tests. The effect of limonene on mechanical properties of PLA films was characterized by an increase in the elongation at break and a decrease in the elastic modulus. The fracture surface structure of films was evaluated by scanning electron microscopy (SEM), and homogeneous surfaces were observed in all cases. Barrier properties were reduced due to the increase of the chain mobility produced by the D-limonene. (C) 2013 Elsevier Ltd. All rights reserved.This research was supported by the Ministry of Science and Innovation of Spain (MAT2011-28468-C02-02). Marina P. Arrieta thanks Generalitat Valenciana (Spain) for a Santiago Grisolia Fellowship. Authors thank Professor Alfonso Jimenez from the University of Alicante, for his useful discussions.Arrieta, MP.; López Martínez, J.; Ferrándiz Bou, S.; Peltzer, MA. (2013). Characterization of PLA-limonene blends for food packaging applications. Polymer Testing. 32(4):760-768. https://doi.org/10.1016/j.polymertesting.2013.03.016S76076832

PLA-PHB/cellulose based films: Mechanical, barrier and disintegration properties

Nanocomposite films based on poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends and synthesized cellulose nanocrystals (CNC) or surfactant modified cellulose nanocrystals (CNCs), as bio-based reinforcement, were prepared by melt extrusion followed by film forming. The obtained nanocomposites are intended for short-term food packaging. Thus, the mechanical, optical, barrier and wettability properties were studied. Functionalized CNCs contribute to enhance the interfacial adhesion between PLA and PHB, leading to improved mechanical stiffness and increased film stretchability. The synergic effects of the PHB and CNCs on the PLA barrier properties were confirmed by increases in oxygen barrier properties and reductions in surface wettability of the nanocomposites. In addition, the measurements of the viscosity molecular weight for ternary systems showed practically no degradation of PLA and smaller degradation of PHB during processing due to nanocrystal presence. The disintegration process in composting conditions of PLA was delayed by the addition of PHB, while CNC speeded it up. PLA-PHB-CNCs formulations showed enhanced mechanical performance, improved water resistance, reduced oxygen and UV-light transmission, as well as appropriate disintegration in compost suggesting possible applications as packaging materials. (C) 2014 Elsevier Ltd. All rights reserved.This research was supported by the Ministry of Science and Innovation of Spain (MAT2011-28468-C02-01 and MAT2011-28468-C02-02). M.P. Arrieta thanks Generalitat Valenciana (Spain) for Santiago Grisolia Fellowship (GRISOLIA/2011/007) and Universitat Politecnica de Valencia for the Development Support Programme PAID-00-12 (SP20120120). The Authors acknowledge Gesenu S.p.a. for compost supply. Authors gratefully thank Prof. Alfonso Jimenez (University of Alicante, Spain) and Prof. Maria Dolores Salvador Moya (Universitat Politecnica de Valencia) for their assistance with OTR measurements and optical microscope-EDF measurements, respectively.Arrieta, MP.; Fortunati, E.; Dominici, F.; Rayón Encinas, E.; López Martínez, J.; Kenny, JM. (2014). PLA-PHB/cellulose based films: Mechanical, barrier and disintegration properties. Polymer Degradation and Stability. 107:139-149. https://doi.org/10.1016/j.polymdegradstab.2014.05.010S13914910