The high accumulation of plastic waste in the environment has led to great interest in biodegradable polymers, such as polylactic acid (PLA) or polyhydroxyalkanoates (PHAs). Their benefits, combined with the application of electrospinning technology, represent an innovative proposal for the food packaging industry. This article provides a comprehensive review of the latest developments of PLA- and PHA-biopolyester-based electrospun materials for food packaging applications, summarizing the reported technologies, material properties, applications, and invention patents. In addition, the legislation used to assess their biodegradability is also detailed. Electrospun packaging materials are largely developed through uniaxial, coaxial, emulsion, multiaxial, and needleless techniques. PLA- and PHA-biopolyester-based electrospun materials can be obtained as single and multilayer packaging structures, and the incorporation of natural extracts, organic compounds, and nanoparticles has become a great strategy for designing active food packaging systems. The biodegradability of electrospun materials has mainly been evaluated in soil, compost, and aquatic systems through ASTM and ISO normatives. In this review, the dependence of the biodegradation process on the polymer type, conditions, and test methods is clearly reviewed. Moreover, these biodegradable electrospun materials have shown excellent antioxidant and antimicrobial properties, resulting in a great method for extending the shelf life of fruits, bread, fish, and meat products.

Hydroxypropyl cellulose (HPC) is a biobased, biodegradable, and water-soluble material that is used as an emulsifier, thickener, and stabilizer in aqueous formulations. Its solid-state properties render HPC also attractive for water-soluble sanitary products, packaging, and biomedical applications. While HPC films and coatings are well-known, HPC fibers have hardly been investigated, arguably, due to the lack of methods to spin HPC fibers. Here, we show that fibers can readily be produced by wet spinning aqueous HPC solutions into an aqueous CaCl₂ coagulation bath. This process induces significant alignment of HPC chains under shear forces, resulting in fibers with considerably higher stiffness (Young's modulus = 1.3 GPa) and tensile strength (36 MPa) than solution-cast HPC films (Young's modulus = 0.7 GPa, tensile strength = 19 MPa). The HPC fibers retain their mechanical integrity upon conditioning at 60% relative humidity, although stiffness is considerably reduced. Wet spinning is readily scalable and affords stiff and strong fibers that represent a promising alternative to woven and nonwoven synthetic fibers.

Matériaux hautement barrière aux gaz associant polylactide et couches minces de nanocellulose en une architecture hiérarchique: Les travaux de cette thèse portent sur l’évaluation des phénomènes de transport à travers un film multicouche biosourcé et biodégradable associant acide polylactide et nanocelluloses. Les excellentes propriétés mécaniques et barrières à l’oxygène des nanocelluloses sont particulièrement intéressantes pour le développement d’emballages alimentaires biosourcés et biodégradables. Cependant, leur hygroscopicité diminue très fortement leur barrière à l’oxygène et il est nécessaire de les associer à un polymère plus hydrophobe, tel que l’acide polylactide (PLA), pour préserver cette propriété. Trois types de nanocelluloses ont été étudiées: nanocristaux, nanofibres et nanofibres oxydées TEMPO (radical 2,2,6,6-tetramethylpiperidin-1-oxy). En raison des différences de polarité entre le PLA et les nanocelluloses, une couche adhésive biosourcée et biodégradable de chitosan a été déposée sur le PLA. Les couches minces de nanocelluloses sont déposées par couchage par barre ou électrofilage. Le dépôt de couches minces accentue le chevauchement et l’orientation des CNC, ainsi que l’enchevêtrement des nanofibres.L’analyse de la structure des échantillons a prouvé l’excellente adhésion entre les différentes couches ainsi que l’obtention de couches nanométriques et homogènes de nanocelluloses. Les propriétés de trans-port de la vapeur d’eau ont montré que les couches minces de nanocelluloses absorbent plus d’eau que des couches micrométriques, mais d’une façon sur-prenante, diminuent la perméabilité à l’eau des échantillons à des humidités relatives de 30%, et 80% dans le cas des CNF TEMPO. En effet, les très fortes interactions chitosan-CNF TEMPO limitent leur sensibilité à l’eau et augmentent leur barrière à l’oxygène.Les films multicouches présentent une perméabilité à l’oxygène 160 fois inférieure à celle du PLA. Cette performance peut être obtenue avec des couches minces,ainsi pour une perméabilité à l’oxygène minimale(1.1x10⁻²⁰m³.m/m².s.Pa) un dépôt de 800 nm de CNC est nécessaire, tandis que 80 nm suffisent avec des CNF TEMPO. L’orientation des nanocelluloses par électrofilage n’a pas eu d’effet sur leurs propriétés barrières.

Mechanically adaptive materials inspired by sea cucumber dermis exhibit reversible, water-tunable mechanical properties, yet their use in sustainable fibers remains unexplored. Here, humidity-responsive nanocomposite fibers based on hydroxypropyl cellulose and cellulose nanocrystals were produced by wet spinning into a CaCl2 coagulation bath. The fibers exhibit moisture-induced disintegration, dense packing and moderate CNC alignment, thereby enabling a percolating network. The Young’s modulus increases from 1.3 GPa for neat HPC to 3.6 GPa for nanocomposites containing 60 wt % CNCs, while the strength and strain at break decrease from 36 to 20 MPa and 3.5 to 0.7%, respectively. Under humid conditions, their Young’s modulus and tensile strength decreased to 18 MPa and 0.4 MPa, while their extensibility increased to 36%. Upon drying, the original mechanical properties of fibers and CaCl2-free films are fully restored. The combination of high stiffness and humidity-induced responsiveness expands the potential of mechanically adaptive nanocomposites for water-dispersible products.