![]() ![]() The advantage of CNCs lies in the worldwide availability of the raw material, economical accessibility, high mechanical strength, high specific surface, biocompatibility, and biodegradability. Its ability to form films and its biocompatibility and biodegradability promotes the use of chitosan as a single-use packaging material, which is the focus of this study.Ĭellulose nanocrystals (CNCs), commonly extracted by acidic hydrolysis of cellulose, have been applied as a reinforcement agent to biopolymer-based films to improve mechanical and barrier properties, bringing such materials closer to achieving protection and user experience comparable to commercial plastic foils and wrappings. These properties are beneficial for a wide range of already commercial applications such as drug delivery, wound dressings, and skin-tissue engineering, as a coagulant, flocculant or adsorbent in wastewater treatment, and as a food additive and dietary fibre. Chitosan is, contrary to chitin, soluble in acidic aqueous media and exhibits antimicrobial activity. Chitosan is obtained from chitin using (partial) deacetylation, and therefore consists of β-D-1,4-glucosamine and N-acetyl-D-glucosamine units linked by glycosidic bonds. The disadvantage of marine waste biomass as a raw material is tropomyosin, a known allergen found in the muscles of crustaceans, leading to the popularization of fungal biomass as a source of chitin. Chitin is found in the shells of crustaceans, a waste product of the food-processing industry, the use of which is in line with circular-economy guidelines. One of the solutions is offered by chitosan, a derivate of chitin-the second most abundant polymer on the planet. Considering that the packaging sector uses a noteworthy amount of all produced plastics (44% in the EU market in 2021 ), along with the fact that these materials also have the shortest lifetime, as it is limited to the lifetime of its contents (e.g., fresh produce), bio-based and biodegradable packaging materials are urgently needed to ensure a cleaner future. In light of recent efforts to find a suitable alternative that would be indispensable in the fight against plastic pollution, marine biomass has become an attractive raw-material source of biopolymers. Lastly, (thermal) stability was assessed by means of the thermogravimetric analysis (TGA) technique, suggesting a slight improvement. It is worth noting that the modification of CNCs improved the best base benchmark stress–strain performance. It was observed that tensile strength was highest upon specimens being dry (25 ± 3 MPa for ALG, reinforced with neat CNCs, or 16 ± 2 MPa in the CH with CNCs, reacting to the highest DS), lowering with dewing, and the elongation at break exhibited the opposite. To evaluate the relationship between environmental humidity and mechanical properties, conditioning was applied for 48 h under controlled relative humidity (33%, 54% and 75%) prior to the evaluation of the mechanical properties and moisture content. The H 2O barrier assessed through applicative vapour transmission (WVT) rate increased with the CNC esterification in CH, but was not influenced in ALG. ![]() Films were evaluated in terms of water contact angle (WCA), which decreased upon CNC addition in either of the biocomposite types. The ATR–FTIR analysis of films demonstrated inter-diffusional structural changes upon the integration of pristine/modified CNCs. An investigation of morphology with scanning electron microscopy (SEM) revealed increased chemical compatibility with the CH matrix after acetylation, producing a smooth surface layer, while ALG mixed better with pristine CNCs. ![]() Cellulose nanocrystals (CNCs) were acetylated to the various parametrised degrees of substitution (DS), determined through attenuated total reflection Fourier transform infrared spectroscopy (ATR–FTIR) and incorporated into alginate (ALG) and chitosan (CH) film-forming solutions. ![]()
0 Comments
Leave a Reply. |