Engineering Breathable Biodegradable Multilayers via Solution Blow Spinning for Sustainable Food Packaging

This study investigated porous materials based on cellulose acetate (CA), poly(lactic acid) (PLA), and their multilayer combinations fabricated by solution blow spinning (SBS) for potential food packaging applications. Single-layer neat polymers and multilayer structures (CA/PLA, CA/PLA/CA, and PLA/CA/PLA) were produced through sequential deposition, enabling control of layer arrangement while preserving high porosity. Attenuated total reflectance Fourier-transformed infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis showed negligible polymer interdiffusion or specific intermolecular interactions, indicating that layer integration occurs mainly through physical contact and void filling rather than molecular mixing. Scanning electron microscopy analysis revealed that cellulose acetate possesses a highly porous, interconnected structure, whereas poly(lactic acid) exhibits a predominantly fibrous morphology with clearly distinguishable layers in multilayer systems. Mechanical testing demonstrated that poly(lactic acid) mats had higher stiffness and tensile strength, while cellulose acetate films were more flexible and compliant. Multilayer systems showed complex tensile behavior characterized by interfacial failure and limited load transfer, indicating no synergistic mechanical reinforcement between layers. Water vapor permeability remained high and narrowly distributed for all configurations (890-920 g·m^-2·day^-1), independent of layer sequence, reflecting the porous morphology. These values exceed those of conventional polymer packaging films, highlighting the suitability of the materials for breathable packaging. Overall, solution blow spinning enables scalable fabrication of biodegradable multilayer materials with tunable mechanical performance for sustainable food packaging applications requiring controlled moisture exchange.