Compatible Ternary Blends of Chitosan/poly(vinyl alcohol)/poly(lactic acid) Produced by Oil-in-Water Emulsion Processing

Abstract

Ternary compatible blends of chitosan, poly(vinyl alcohol), and poly(lactic acid) were prepared by an oil-in-water (O/W) emulsion process. Solutions of chitosan in aqueous acetic acid, poly(vinyl alcohol) (PVA) in water, and poly(lactic acid) (PLA) in chloroform were blended with a high-shear mixer. PVA was used as an emulsifier to stabilize the emulsion and to reduce the interfacial tension between the solid polymers in the blends produced. It proved to work very well because the emulsions were stable for periods of days or weeks and compatible blends were obtained when PVA was added. This effect was attributed to a synergistic effect of PVA and chitosan because the binary blends PVA/PLA and chitosan/PLA were completely incompatible. The blends were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal mechanical analysis (TMA), stress-strain tests, and Fourier transform infrared spectroscopy (FTIR). The results indicated that despite the fact that the system contained distinct phases some degree of molecular miscibility occurred when the three components were present in the blend.

Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

“…1c-f). This same upward shift has already been reported for blends of CS with PLA [12]. The intensity of this peak was higher in the absence of MDI and is most likely due to the heterogeneous nature of the PLA/CS blend without MDI, leading to a higher composition of PLA in the analyzed wavelength.…”

“…A c c e p t e d M a n u s c r i p t 12 In summary, increasing the amount of MDI had increased the number of urethane groups leading to a higher degree of cross-linking between PLA and CS polymer chains as well as an increase in H-bonding. This affected the adhesion properties of the PLA/CS blends as shown in sections 3.2-3.4.…”

“…The peak observed at 1745cm -1 in pure PLA (Fig. 1a), which has been attributed to the C=O stretching associated with ester groups [12,24], was observed at 1755cm -1 in all of the PLA/CS blends (Fig. 1c-f).…”

Biodegradable Blends with Potential Use in Packaging: A Comparison of PLA/Chitosan and PLA/Cellulose Acetate Films

“…Many efforts to produce polymeric coatings and blends incorporating chitosan or cellulose acetate into biodegradable polyesters such as PLA are reported in the literature [16][17][18][19][20][21]. Biodegradable blends from the solubilization of plasticized chitosan into different polymers such as PLA, starch, and poly(vinyl acetate) (PVA) followed by casting to obtain films have been reported [16][17][18][19].…”

“…Biodegradable blends from the solubilization of plasticized chitosan into different polymers such as PLA, starch, and poly(vinyl acetate) (PVA) followed by casting to obtain films have been reported [16][17][18][19]. A new approach involving the incorporation of plasticized chitosan into PLA, by extrusion followed by coating with a chitosan solution, to enhance the antimicrobial action has also been reported [20].…”