High‐pressure treatment of water‐filled co‐extruded polylactide films: Effect on microstructure, barrier, thermal, and rheological properties

Abstract

The impact of high‐pressure treatments (450 and 600 MPa) on the morphological, thermal, structural, and barrier properties of commercial coextruded polylactide (PLA) packaging films has been explored to evaluate their applicability in food processing. Pouches filled with water as a food simulant were subjected to high‐pressure treatment for 15 min at ambient temperature. Results indicated no significant changes in the visual appearance, color, integrity, or water barrier properties of the post‐process pouches. However, high‐pressure treatment affected mechanical property results. Thermal analysis of the film showed endothermic double melting peaks (165.12 and 170.55°C), which did not change with the pressurization; however, the exothermic crystallization peak (118.08°C) varied significantly. Both SEM and AFM micrographs demonstrated that the surface morphology and roughness parameters (arithmetic mean [Sa] and root mean square height [Sq]) of the films were significantly affected by the HP treatment, which is further complemented by the FTIR spectra and XRD diffractogram. Melt rheology (175–205°C) of the pressure‐treated films showed a significant drop (20–30%) in mechanical rigidity (G′) when compared to the untreated sample. Changes in the microstructure/crystallinity in the PLA films were indicated by van Gurp and Palmen plot. Practical Application The results reported here can help to improve the design of the coextruded packaging materials so that it can be successfully implemented to high‐pressure processing and high pressure‐assisted thermal processing of food.

Effect of High-Pressure Processing on the Packaging Properties of Biopolymer-Based Films: A Review

“…This enhancement in WVP could also be due to the formation of holes and cavities on the film structure during HPP. Such an increasing trend in WVP with the increase in pressure level was observed in the case of co-extruded PLA films, where, the WVP of the untreated film (1.55 ± 0.12) × 10 −14 (kg·m/[m 2 ·s·Pa]) increased to (1.59 ± 0.10) × 10 −14 and (1.62 ± 0.13) × 10 −14 (kg·m/[m 2 ·s·Pa]) when subjected to 450 and 600 MPa [ 58 ]. The authors state that the reduction in the crystallization of the co-extruded film might have facilitated the transport of water vapor and thus enhanced the permeability.…”

Effect of Mortise and Tenon Structure on the Properties of Wood Flour Polyvinyl Chloride-Laminated Veneer Lumber Co-Extruded Composites

“…A composite combining the performance characteristics of WPC and LVL, i.e., strong weather resistance, high mechanical strength, and strong creep resistance can be prepared by co-extrusion molding technology. This technology involves the use of two or more extruders to continuously extrude two-phase or multiple materials into multilayer composite materials through specific molds [23][24][25]. At present, co-extrusion technology has been applied to the production and preparation of WPC composites, namely Co-WPCs.…”