Barrier Properties of Polylactic Acid in Cellulose Based Packages Using Montmorillonite as Filler

Abstract

Polylactic acid (PLA) and montmorillonite (CB) as filler were studied as coatings for cellulose based packages. Amorphous (AM) and semi crystalline (SC) PLA were used at different concentrations according to a 2 × 6 × 3 full factorial experimental design. CB loading was three concentrations and coating was performed by casting. Contact angle (CA), water vapor (WVP) and grease permeabilities were measured for each resultant package and were compared to commercial materials (Glassine Paper, Grease Proof Papers 1 and 2 produced commercially). Significant differences were found and the main factors were the type and concentration of PLA. The best values were: for grease penetration, +1800 s; WVP from 161.36 to 237.8 g·µm·kPa and CA from 69° to 73° for PLA-AM 0.5% and CB variable. These parameters are comparable to commercial packages used in the food industry. DSC revealed three different thermal events for PLA-SC and just T g for PLA-AM. Crystallinity was also verified, obtaining a ΔH crys of 3.7 J·g

Preparation and characterization of poly(lactic acid)/poly(ethylene oxide) blend film: effects of poly(ethylene oxide) and poly(ethylene glycol) on the properties

“…6, a WCA of approximately 65 ∘ can aptly foster the reliability of the films in short-term food packaging application. 33,34 Scanning electron microscopy PLA film was free of any voids as depicted in Fig. 7(a), whereas PLA/4 wt% PEO film was full of pores ranging from approximately 2 to 5 m. This porous microstructure of the PLA/4 wt% film accounted for the inferior barrier property, facilitating diffusion pathways for both oxygen and water vapour.…”

Bio-Based Coatings for Paper Applications

“…Several biopolymers such as PLA [98], PHB [99], and chitosan [100] have been intercalated into clay to form bionanocomposites films with improved barrier properties against water vapor and oxygen permeability. Application of these bionanocomposites as a coating over paper is a common route to achieve the barrier against water vapor, gases, water and grease [100,101]. For paper coating application, the large aspect ratio of nanoclay (around 50-1000) compared with a standard clay pigments (10-30) creates a more tortuous path for diffusion of air and gas molecules resulting in lower permeability.…”

“…The bionanocomposite paper coatings have been developed by mixing PLA and modified MMT in methylene chloride solution and application by solvent casting [101]: the barrier properties of PLA-MMT coated papers highly depend on the crystallinity and concentration of PLA and are comparable with commercially coated papers, in terms of water contact angle (up to 73°), WVP (up to 237.8 g μm/(m 2 ·24 h·kPa)) and grease permeability (+1800 s). However, the incorporation of clay in the PLA matrix does not affect the barrier properties significantly but it rather acts as a nucleating agent as determined by the improved thermal properties.…”

Development and characterization of nano‐crystalline cellulose incorporated poly(lactic acid) composite films

“…The highest values were obtained with 10 % (w/w) nano-crystalline cellulose addition. The load bearing capacity of the composite films were enhanced due to efficient shifting of stress from matrix to nano-crystalline cellulose fillers and robust hydrogen bonding between the hydroxyl groups existing in lignocelluloses in cotton fibers [21,22]. The composite films are stronger and more flexible, Figure 6.…”