Next Article in Journal
Magnetite-Accelerated Corrosion of SA508 Tubesheet Material and Its Effect on Steam Generator Tube Denting
Previous Article in Journal
Numerical Study on the Optimization of Roll-to-Roll Ultraviolet Imprint Lithography
Previous Article in Special Issue
Coating of Nanolipid Structures by a Novel Simil-Microfluidic Technique: Experimental and Theoretical Approaches
Open AccessFeature PaperArticle

Poly (Lactic Acid)/Thermoplastic Starch Films: Effect of Cardoon Seed Epoxidized Oil on Their Chemicophysical, Mechanical, and Barrier Properties

1
Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant’Angelo, 80126 Naples, Italy
2
Programa de Ingeniería de Alimentos, Facultad de Ingeniería, Universidad de Cartagena, Food Pakaging and Shelf Life Research Group, Carrera 6 # 36-100, Cartagena de Indias D.T y C 130001, Colombia
3
Institute for Polymers, Composites and Biomaterials, National Council of Research, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
4
Instituto de Ingeniería de Alimentos para el Desarrollo, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain
5
Institute of Applied Sciences and Intelligent Systems, National Council of Research, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
6
International Research Organization for Advanced Science and Technology (IROAST), University of Kumamoto, Kumamoto 860-8555, Japan
*
Author to whom correspondence should be addressed.
Coatings 2019, 9(9), 574; https://doi.org/10.3390/coatings9090574 (registering DOI)
Received: 1 August 2019 / Revised: 29 August 2019 / Accepted: 2 September 2019 / Published: 8 September 2019
(This article belongs to the Special Issue Coatings and Interfacial Films for Food Applications)
In this work, biodegradable films based on poly (lactic acid) (PLA) and corn thermoplastic starch (TPS), additivated with epoxidized cardoon oil plasticizer (ECO) at 3% by weight with respect to PLA mass fraction, were prepared by melt extrusion process and compression molding. The effect of ECO on structural, thermal, mechanical, barrier, and spectral optical properties of the films was investigated. Spectroscopic analysis evidenced the development of physical interaction between oil and polymers, mainly PLA. In addition, no oil migration occurrence was detected after six months of film preparation, as evidenced by oil mass evaluation by precipitation as well as by 1H-NMR methods, thus highlighting the good inclusion of oil inside the polymeric network. The plasticizing action of the oil induced a lean improvement of the interfacial adhesion between hydrophobic PLA and hydrophilic TPS, particularly accentuated in PLA80_ECO composition, as evidenced by morphological analysis of blend fracture surfaces. TGA data underlined that, differently from TPS-based films, PLA-based systems followed one degradative thermal profile suggesting a slight compatibilization effect of epoxidized oil in these films. The shifting of Tg values, by differential scanning calorimetry (DSC) analysis, indicated a weak miscibility at molecular level. Generally, in the investigated blends, the phase separation between PLA and TPS polymers was responsible for the mechanical properties failing; in particular, the tensile strength evidenced a negative deviation from the rule of mixtures, particularly marked in TPS-based blends, where no physical entanglements occurred between the polymers since their immiscibility even in presence of ECO. The epoxidized oil strongly improved the barrier properties (water vapor permeability (WVP) and oxygen permeability (O2P)) of all the films, likely developing a physical barrier to water and oxygen diffusion and solubilization. With respect to neat PLA, PL80 and PL80_ECO films evidenced the improvement of surface wettability, due to the presence of polar groups both in TPS (hydroxyl residues) and in epoxidized oil (oxirane rings). Finally, following to the conditioning in climatic chamber at T = 25 °C and RH = 50%, PLA80 film became opaque due to TPS water absorption, causing a light transmittance decreasing, as evidenced by spectral optical analysis. View Full-Text
Keywords: biomass recovery; cardoon epoxidized oil; poly (lactic acid); thermoplastic starch; bioplastics biomass recovery; cardoon epoxidized oil; poly (lactic acid); thermoplastic starch; bioplastics
Show Figures

Graphical abstract

MDPI and ACS Style

Turco, R.; Ortega-Toro, R.; Tesser, R.; Mallardo, S.; Collazo-Bigliardi, S.; Chiralt Boix, A.; Malinconico, M.; Rippa, M.; Di Serio, M.; Santagata, G. Poly (Lactic Acid)/Thermoplastic Starch Films: Effect of Cardoon Seed Epoxidized Oil on Their Chemicophysical, Mechanical, and Barrier Properties. Coatings 2019, 9, 574.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map

1
Back to TopTop