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The technology of food packaging is responding to significant market dynamics such as the rapid growth in e-commerce and preservation of fresh food, a sector that accounts for over 40% of plastic waste. Further, mandates for sustainability and recent changes in national governmental policies and regulations that include banning single-use plastic products as observed in sweeping reforms in Europe, Asia, and several US States are forcing industries and consumers to find alternative solutions. This review highlights an ongoing shift of barrier coatings from traditional synthetic polymers to sustainable breakthrough materials for paper-based packaging and films. Advantages, challenges and adapting feasibility of these materials are described, highlighting the implications of selecting different materials and processing options. A brief description on progress in methods of coating technologies is also included. Finally, the end fate of the barrier materials is classified depending on the packaging type, coating materials used and sorting facility availability. Different types of coatings, such as water-based biopolymers, due to their greater environmental compatibility, are making inroads into more traditional petroleum-based wax and plastic laminate paperboard products for fresh food bakery, frozen food, and take-out containers applications. In addition, nano-biocomposites have been studied at an accelerating pace for developing active and smart packaging. Based on the momentum of recent developments, a strong pace of continuing developments in the field can be expected. [Display omitted] • Top trends in food packaging are driven by sustainability, e-commerce, and the end fate of the materials. • Recent developments in bio-based materials have the potential of replacing petro-based polymers. • High speed and specialized coating methods have emerged in the past few years for food packaging development. • Businesses are focused on the recycling of synthetic and biopolymers. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new pathway for sustainable packaging materials was engineered by formulating multilayer CNF/CNC barrier coatings. • CNF and CNC synergistically enabled high oil and grease resistance (a kit rating of 11) comparable to fluorochemicals. • A significant reduction in oxygen transmission rate was demonstrated (∼by a factor of about 260) compared to uncoated paper. • Sustainable biomaterials are relevant to society's ongoing efforts to improve health, safety, and environmental stewardship. Abstract Cellulose derivatives such as cellulose nanofibers (CNF) and cellulose nanocrystals (CNC) have enormous potential to reduce or replace petroleum and fluorochemicals for food and other packaging applications. CNFs have been studied for their excellent oxygen and gas barrier properties; however, their performance rapidly decreases in the presence of moisture and higher humidity. CNCs are less sensitive to moisture due to their highly crystalline nature; however, coatings and films made of CNCs are much more prone to fracture due to their high brittleness. Our work demonstrates a unique composite barrier coating system of CNF and CNC that synergistically enables oil and grease resistance (a kit rating of 11) comparable to fluorochemicals. It also demonstrates a significant increase in air resistance (∼by a factor of about 300), and a reduction in oxygen transmission rate (∼by a factor of about 260) compared to uncoated paper. The improvements in oil and gas barrier properties were evaluated with respect to the molecular, chemical, and structural properties of the developed coatings. [ABSTRACT FROM AUTHOR]

This review article was prompted by a remarkable growth in the number of scientific publications dealing with the use of nanocellulose (especially nanofibrillated cellulose (NFC), cellulose nanocrystals (CNC), and bacterial cellulose (BC)) to enhance the barrier properties and other performance attributes of new generations of packaging products. Recent research has confirmed and extended what is known about oxygen barrier and water vapor transmission performance, strength properties, and the susceptibility of nanocellulose-based films and coatings to the presence of humidity or moisture. Recent research also points to various promising strategies to prepare ecologically-friendly packaging materials, taking advantage of nanocellulose-based layers, to compete in an arena that has long been dominated by synthetic plastics. Some promising approaches entail usage of multiple layers of different materials or additives such as waxes, high-aspect ratio nano-clays, and surface-active compounds in addition to the nanocellulose material. While various high-end applications may be achieved by chemical derivatization or grafting of the nanocellulose, the current trends in research suggest that high-volume implementation will likely incorporate water-based formulations, which may include water-based dispersions or emulsions, depending on the enduses. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extraction of lignin-containing cellulose nanofibers (LCNF) from hemp hurds waste. • Development of LCNF coatings/films with reduced polarity and low hydrophilicity. • Elucidation of the role of lignin content and distribution on barrier properties. • Significantly higher water contact angle with LCNF coatings and films. • LCNF-based coatings/films can contribute to a circular economy and sustainability. Residual hemp (Cannabis sativa) hurd fibers obtained from hydrothermal, carbonate, and kraft treatments were the resources used to obtain lignocellulosic nanofibers (LCNF) by using an ultra-fine friction grinder. The morphological, crystallinity, and chemical characteristics of the nanocellulose films were carried out using SEM, XRD, EDX and ToF-SIMS. Water barrier properties of the same were measured in terms of water contact angle, water vapor permeability (WVP) and water absorption. The barrier properties were found to be dependent not only on the lignin content and lignin distribution, but also on the film density and porous structure. LCNF films and coatings showed much higher water contact angle (WCA) (80°-102°) than films produced from the bleached CNF. WVP was found to be more dependent on the density of films than lignin content. Overall, LCNF-based films and coatings derived from hemp hurd residual fibers can contribute to a circular economy and sustainability. [ABSTRACT FROM AUTHOR]