Chitin Nanocrystals Provide Antioxidant Activity to Polylactic Acid Films

From fundamental insights to rational (bio)polymer nanocomposite design - Connecting the nanometer to meter scale

Nanoparticle addition has the potential to make bioplastic use mainstream, as the resultant nanocomposite shows improved mechanical, barrier, and thermal properties. It is well established that the architecture and dynamics of the nanoparticle-polymer interphasial region, ∼ 1.5-9 nm from the nanoparticle surface, are crucial for nanocomposite characteristics. Yet, how these molecular phenomena translate to the bulk is still largely unknown. A multi-disciplinary and multi-scale vision is required to capture the full picture and improve materials far beyond what is currently possible. In this review, a first step in bridging the apparent gap between fundamental insights toward observed material properties is made. At the molecular scale, the polymer chain density and dynamics at the nanoparticle surface are governed by a complex interplay between enthalpy and entropy. The resultant interphasial properties can only be propagated to the macroscopic scale effectively when the nanoparticles are well-distributed. This makes the dispersion state a key parameter for which thermodynamic and kinetic insights can be used to prevent nanoparticle aggregation. These insights are linked to material properties relevant to packaging. The outlook section elaborates on the remaining challenges and the steps required to further understand and better design nanocomposite systems.

Advances in chitin-based nanoparticle use in biodegradable polymers: A review

Chitin-based nanoparticles are polysaccharide materials that can be produced from a waste stream of the seafood industry: crustacean shells. These nanoparticles have received exponentially growing attention, especially in the field of medicine and agriculture owing to their renewable origin, biodegradability, facile modification, and functionality adjustment. Due to their exceptional mechanical strength and high surface area, chitin-based nanoparticles are ideal candidates for reinforcing biodegradable plastics to ultimately replace traditional plastics. This review discusses the preparation methods for chitin-based nanoparticles and their applications. Special focus is on biodegradable plastics for food packaging making use of the features that can be created by the chitin-based nanoparticles.

Comparison of the Degree of Acetylation of Chitin Nanocrystals Measured by Various Analysis Methods

Chitin and its derivate chitosan have versatile properties and have been used in various applications. One key parameter determining the functionality of chitin-based materials is the degree of acetylation (DA). For DA determination, NMR and FTIR spectroscopy are often considered to be the gold standard, but these techniques may not always be available and are rather time-consuming and costly. The first derivative UV method has been suggested, although accurate measurements can be challenging for materials with high degrees of acetylation, due to hydroxymethylfurfural (HMF) formation and other side reactions occurring. In this paper, we re-evaluated the first derivate UV method for chitin and chitosan powder, chitin nanocrystals, and deacetylated chitin nanocrystals. Our results showed that the first derivative UV method is capable of measuring DA with high accuracy (>0.9), leading to values comparable to those obtained by 1H NMR, 13C NMR, and FTIR. Moreover, by-product formation could either be suppressed by selecting the proper experimental conditions, or be compensated. For chitin nanocrystals, DA calculation deviations up to 20% due to by-product formation can be avoided with the correction that we propose. We conclude that the first derivative UV method is an accessible method for DA quantification, provided that sample solubility is warranted.