High-Strength, Low-Permeable, and Light-Protective Nanocomposite Films Based on a Hybrid Nanopigment and Biodegradable PLA for Food Packaging Applications.

Herein, a multifunctional filler, a dye (organic)-clay (inorganic) hybrid nanopigment (DCNP), was embedded into polylactic acid (PLA) to fabricate a colored biodegradable/biocompatible film, which is explored as a high thermomechanical resistant as well as a superior light and mass transport barrier for food packaging applications. In this respect, the DCNP was synthesized through a wet chemical process with a reaction yield of 76% and incorporated into a PLA matrix at various concentrations using a solution casting method. The morphological characterizations revealed partially intercalated/exfoliated structure for PLA-DCNP films. The samples filled with DCNP showed up to 20% and 12 °C improvements in storage modulus (E') and glass transition temperature (T g), respectively, compared to those with neat PLA. Incorporation of a small amount of DCNP into the PLA matrix significantly declined the water vapor and gas permeability of PLA by 36 and 54%, respectively. The optical property investigations indicated remarkable color characteristics and light protection performance of the samples containing DCNP. The results also showed better performance of the PLA-DCNP film compared to that of the PLA-Cloisite 20A sample at an identical filler loading. In conclusion, the desirable properties of the resulting films highlighted the potential application of such nanocomposite films as a promising option for food packaging materials.

Factors affecting the properties of nitrocellulose emulsions: A comparative study.

In this study the influence of viscosity and chemical nature of dispersed phase, preparation conditions and storage temperature on the properties of nitrocellulose emulsions produced by gel emulsification (G) and direct mechanical emulsification (D) methods were examined. Chemical nature of dispersed phase had no effect on the drop size for both methods; however it had a significant effect on emulsion stability. Viscosity of dispersed phase did not considerably affect drop breakage process in route G, while strongly affected drop breakage in route D. Addition rate had no significant effect on the drop size produced by route D; while for route G high addition rate resulted in catastrophic phase inversion. The drop size produced by route D decreased dramatically by increasing stirring speed, whereas stirring speed had a minimal effect on the drop breakage process in route G. Finally, it was found that emulsion stability was greatly influenced by storage temperature.