Effect of natural and synthetic antioxidants incorporation on the gas permeation properties of poly(lactic acid) films

authors	Goncalves, CMB; Tome, LC; Garcia, H; Brandao, L; Mendes, AM; Marrucho, IM
nationality	International
journal	JOURNAL OF FOOD ENGINEERING
author keywords	Poly(lactic acid) (PLA) films; Antioxidants; Time-lag; Gas barrier properties
keywords	MECHANICAL-PROPERTIES; POLYLACTIC ACID; BARRIER PROPERTIES; BIODEGRADABLE POLYMERS; BUTYLATED HYDROXYTOLUENE; SEPARATION MEMBRANES; SURFACE MODIFICATION; POLY(L-LACTIC ACID); ALPHA-TOCOPHEROL; BLENDS
abstract	Gas permeation properties (permeability, diffusivity and solubility coefficients) were determined for carbon dioxide and oxygen in poly(lactic acid) (PLA) films enriched with 0, 2, 4 and 10 wt.% of different antioxidants, at three temperatures, 284, 293 and 303 K, using a time-lag apparatus. Three antioxidants, a natural, alpha-tocopherol (AT), and two synthetic, butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), were tested. DSC results show that the polymer glass transition temperature slightly decreases with the increase of the antioxidant content. The crystallinity degree of PLA films decreases with the addition of BHT and TBHQ whereas the incorporation of AT increases the crystallinity of PLA films. The permeability towards water vapour, at 299 K and 45% of relative humidity, and surface energy show a decreased in the wettability of the prepared materials with the increase of the antioxidants content. The incapacity to measure gas permeation in PLA films with 10 wt.% of AT and BHT incorporated was due to phase separation, proved by SEM images. The CO2 and O-2 permeation results show that PLA barrier properties can be improved by the incorporation of antioxidants but are strongly dependent on the amount and structure of the antioxidant added. (C) 2013 Elsevier Ltd. All rights reserved.
publisher	ELSEVIER SCI LTD
issn	0260-8774
year published	2013
volume	116
issue	2
beginning page	562
ending page	571
digital object identifier (doi)	10.1016/j.jfoodeng.2012.12.034
web of science category	Engineering, Chemical; Food Science & Technology
subject category	Engineering; Food Science & Technology
unique article identifier	WOS:000317255400037