Polylactic acid (PLA) nanocomposite films represent a sustainable alternative to conventional petroleum-based plastics in active food packaging, offering a path to reduce post-consumer solid waste while extending perishable food shelf life. Integrating agricultural by-products, such as banana waste cellulose micro/nanofibers, enhances mechanical and barrier properties, while incorporating active antimicrobial agents like lauric arginate ethyl ester (LAE) provides targeted inhibition against foodborne pathogens. However, a critical operational transition remains between formulating active biopolymer films in controlled laboratory environments and deploying these materials across high-speed industrial converting and food packaging lines. This perspective examines key operational discrepancies, including active agent thermal degradation during melt processing, phase separation between hydrophobic polymer matrices and hydrophilic cellulosic reinforcements, controlled active agent release kinetics under variable storage conditions, and the lack of standardized shelf-life validation protocols in commercial supply chains. To transition active PLA-cellulose-LAE formulations into standard packaging practice, we present a forward-looking roadmap emphasizing interface compatibility engineering, thermal processing window optimization, controlled release kinetic modeling, and continuous active packaging quality auditing.
Forward roll coating is an industrial technique that is used to applies a thin protective liquid layer on a moving surface. The process of forward roll coating using the Ellis fluid is modeled in form of differential equations. These complex differential equations governing polymer motion are simplified using lubrication approximation theory due to the thin-film geometry. Both analytical and numerical methods are employed to determine the velocity field, pressure gradient, pressure distribution, and flow rate. Key coating features, such as film thickness and separation points, are also calculated. This study explores in detail how the inverse capillary number, Ellis fluid parameters, and power-law index affect the coating process. Results reveal that non-Newtonian effects significantly influence coating thickness and flow behavior. Shear-thinning behavior in the Ellis model reduces pressure and delays separation points, also enhancing coating smoothness. It is also noted that inverse capillary ( 1 N C a 2 ) number increases the separation point and coated thickness 12.80% and 20.26% as 1 N C a 2 increases from 0 to 2 for fixed α = 1 . For the same 1 N C a 2 and α = 2 the increased separation point and coated thickness are 6.99% and 10.99%. These effects for the pertinent parameters are shown through figures and tables, which illustrate how these parameters impact coating characteristics. Results confirm that Ellis’s fluid parameters play a crucial role in controlling coating thickness, separation points, and pressure distribution.
In this study, a polytetrafluoroethylene (PTFE)-modified waterborne copolyester composite coating was developed by uniformly incorporating PTFE into an environmentally friendly waterborne copolyester matrix. The waterborne copolyester offers distinct eco-friendly advantages, along with excellent adhesion to PET substrates and high flexibility, making it particularly suitable for photovoltaic module backsheets. The microstructure, tribological properties, and environmental service reliability of the resulting coating were systematically investigated. The PTFE effectively reduced the coefficient of friction between the coating and the counterpart ball and promoted the formation of a stable transfer film, thereby enabling a continuous reduction in wear. Compared with the pure waterborne copolyester coating, the wear rate of the PTFE-modified coating decreased by 19.1%. This enhanced tribological performance is attributed to a continuous film-forming network established by PTFE within the waterborne copolyester matrix. Furthermore, PTFE synergistically reinforced the matrix, generating a “soft–hard” composite structure. At the optimal 10% PTFE content, the soft and hard phases were uniformly distributed, delivering the greatest friction reduction and wear resistance. Combining the intrinsic environmental benefits, strong PET adhesion, and high flexibility of the waterborne copolyester, this approach provides a promising new strategy for developing high-performance wear-resistant coatings for photovoltaic module backsheets.
