No abstract

Abstract. Blends of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB) plasticized with a lactic acid oligomer (OLA) added at three different concentrations (15, 20 and 30 wt% by weight), were prepared by an optimized extrusion process to improve the processability and mechanical properties of these biopolymers for flexible film manufacturing. Morphological, chemical, thermal, mechanical, barrier and migration properties were investigated and formulations with desired performance in eco-friendly films were selected. The efficiency of OLA as plasticizer for PLA_PHB blends was demonstrated by the significant decrease of their glass transition temperatures and a considerable improvement of their ductile properties. The measured improvements in the barrier properties are related to the higher crystallinity of the plasticized PLA_PHB blends, while the overall migration test underlined that all the proposed formulations maintained migration levels below admitted levels. The PLA_PHB blend with 30 wt% OLA was selected as the optimum formulation for food packaging, since it offered the best compromise between ductility and oxygen and water vapor barrier properties with practically no migration. Vol.9, No.7 (2015) 583-596 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2015.55 * Corresponding author, e-mail: ilaria.armentano@unipg.it © BME-PT In contrast to the development of novel polymeric materials and new polymerization routes, blending is a relatively cheap and fast method to tailor the plastics properties. As a result, this approach may play a crucial role in increasing the competitiveness of biopolymers [2][3][4][5]. Poly(lactic acid) (PLA) thereby represents the most investigated aliphatic polyester for a wide range of applications, due to its biodegradability, renewability and excellent mechanical properties, good processability and low cost [6,7]. It is now produced on a large scale and used for various applications in different domains: packaging, medicine, agriculture and textiles. However, high brittleness, slow crystallization rate and low barrier properties of PLA compared to those of synthetic polymers strongly limit its applications in, for instance, food packaging [6]. Several strategies have been attempted for PLA to enhance its crystallization rate as well as to improve its barrier properties. Blending of PLA with other biopolymers or conventional synthetic polymers is one of the most effective methods to obtain new properties required for specific end-use applications [8,9]. For example, blending PLA with poly(hydroxybutyrate) (PHB), a highly crystalline biopolymer with high melting point and among the most studied polyhydroxyalkanoates (PHAs), leads to materials with interesting physical, thermal, and mechanical properties compared to neat PLA [10][11][12]. PLA and PHB are biodegradable polyesters and they are used in consumer products by several industrial sectors due to their biocompatibility, biodegradability and sustainability [6,12,13]. They have comparab...

No abstract

On the use of tris(nonylphenyl) phosphite as a chain extender in melt-blended poly(hydroxybutyrate-co-hydroxyvalerate)/ clay nanocomposites: Morphology, thermal stability, and mechanical properties J. González-Ausejo, E. Sánchez-Safont, J. Gámez-Pérez and L. Cabedo, J. Appl. Polym. Sci. 2015, DOI: 10.1002 Characterization of polyhydroxyalkanoate blends incorporating unpurified biosustainably produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) A. Martínez-Abad, L. Cabedo, C. S. S. Oliveira, L. Hilliou, M. Reis and J. M. Lagarón, J. Appl. Polym. Sci. 2015, DOI: 10.1002 Modification of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) ABSTRACT: Active edible films represent one of the current and future trends in the development of new polymers for selected applications, particularly food packaging. Some biopolymers show excellent performance as carriers for active compounds extracted from natural sources and are able to be released at a controlled rate to packaged food. In this review we aim to present, in a comprehensive way, the most recent advances and updates in this subject, where much research is currently ongoing and new studies are reported very often. This review focuses on innovative biopolymer matrices, their processing to obtain edible active films, and present and future applications.

Abstract:The most fashionable trends in food packaging research are targeted towards improvements in food quality and safety by increasing the use of environmentally-friendly materials, ideally those able to be obtained from bio-based resources and presenting biodegradable characteristics. Edible films represent a key area of development in new multifunctional materials by their character and properties to effectively protect food with no waste production. The use of edible films should be considered as a clean and elegant solution to problems related with waste disposal in packaging materials. In particular, pectin has been reported as one of the main raw materials to obtain edible films by its natural abundance, low cost and renewable character. The latest innovations in food packaging by the use of pectin-based edible films are reviewed in this paper, with special focus on the use of pectin as base material for edible coatings. The structure, properties related to the intended use in food packaging and main applications of pectins are herein reported.