Transparent Films Based on PLA and Montmorillonite with Tunable Oxygen Barrier Properties

Abstract

Polylactide (PLA) is viewed as a potential material to replace synthetic plastics (e.g., poly(ethylene terephthalate) (PET)) in food packaging, and there have been a number of developments in this direction. However, for PLA to be competitive in more demanding uses such as the packaging of oxygen-sensitive foods, the oxygen permeability coefficient (OP) needs to be reduced by a factor of ∼10. To achieve this, a layer-by-layer (Lbl) approach was used to assemble alternating layers of montmorillonite clay and chitosan on extruded PLA film surfaces. When 70 bilayers were applied, the OP was reduced by 99 and 96%, respectively, at 20 and 50% RH. These are, to our knowledge, the best improvements in oxygen barrier properties ever reported for a PLA/clay-based film. The process of assembling such multilayer structures was characterized using a quartz crystal microbalance with dissipation monitoring. Transmission electron microscopy revealed a well-ordered laminar structure in the deposited multilayer coatings, and light transmittance results demonstrated the high optical clarity of the coated PLA films.

Nacre-mimetics with synthetic nanoclays up to ultrahigh aspect ratios

“…Table 3 compares all materials at high relative humidity. High relative humidity poses challenging conditions for gas barriers based upon water-soluble polymers, as increased free volume and plasticization allow faster diffusion of gas molecules [32][33][34]37,68 . Interestingly, the smaller synthetic nanoclays actually outperform previously investigated PVA/ MTM 36 , despite the fact that the weight fraction of nanoclay is lower.…”

Phosphorus-containing flame retardant modified layered double hydroxides and their applications on polylactide film with good transparency

“…The potential of polylactide (PLA) material as a sustainable replacement for traditional petrochemical-derived polymers has received much attention recently because of its acceptable physical, mechanical properties and high transparency in the application fields of paper coating, fibers, films, and packaging [1][2][3][4]. However, some intrinsic properties of PLA, such as low thermal stability, high combustibility, and melt dripping significantly restrict its expansion into new application areas, such as engineering plastics, biomaterials, and flexible electronics [5][6][7][8][9].…”

Thermal, rheological and mechanical properties of poly(propylene carbonate)/methyl methacrylate–butadiene–styrene blends

“…Researchers have made great efforts to discover ecofriendly materials to replace conventional materials synthesized from petroleum [1][2][3]. The synthesis of poly(propylene carbonate) (PPC) from CO 2 and propylene oxide (PO), which was first reported in 1969 by Inoue [4,5], has attracted extensive attention not only for its utilization of CO 2 as an effective way to reduce greenhouse effect, but also for its good biodegradability and biocompatibility [6][7][8].…”