Stimuli-triggered multilayer films in response to temperature and ionic strength changes for controlled favipiravir drug release

The application and promotion of biodegradable plastics are hindered by the imbalance between their mechanical and degradation performance imbalance, as well as high costs. Herein, a series of poly(ethylene adipate‐co‐terephthalate) (PEAT) copolyesters with excellent mechanical and degradation properties are synthesized by one‐step melt polycondensation. The influence of the proportion of aliphatic groups in the molecular chain on the structure and properties, especially the degradation performance, of the copolyesters was studied. The molecular chain flexibility and degradability of PEAT increases with increasing of adipic acid content and decreasing of ET fragment length (LET). The comprehensive mechanical properties of PEAT60 can be comparable to traditional packaging material poly(butylene adipateco‐terephthalate) (PBAT). The degradation performance of PEAT can be adjusted the molecular chain structure. PEAT with LET < 3 exhibit degradation performance, and PEAT with LET < 2.2 exhibit significant degradation acceleration. The excellent mechanical and degradable properties of PEAT copolyester make it expected to be used in degradable packaging and other fields to help solve plastic pollution, while its lower cost will aid in the promotion of degradable materials.

Seawater‐degradable poly(ethylene adipate‐co‐terephthalate) copolyester: Synthesis, properties, and degradation behavior

Liu,

Wang,

Yin

et al. 2024

Effect of fiber orientation on the mechanical properties of a biodegradable composite made from lyocell‐fiber reinforced polybutylene adipate terephthalate

Cordin,

Bechtold,

Ngo

et al. 2024

Polymer waste in the environment is a more and more serious problem for nature. Therefore, the industry is increasingly interested in the use of materials that are biodegradable. Polybutylene adipate terephthalate (PBAT) belongs to the group of biodegradable polymers, but this polymer often does not have the desired properties for many uses. Therefore, this polymer is often mixed with other biodegradable polymers to form blends with suitable properties. An alternative is, to change the polymer's properties with the addition of fibers. The aim of the present work is to use lyocell fibers to improve the mechanical properties of PBAT. Lyocell is an eco‐friendly cellulose fiber that is biodegradable. The lyocell fibers were embedded into a PBAT matrix in the form of a woven fabric, with different orientations of the fabric warp yarns to the long axis of composites. Consequently, composites with a warp yarn orientation of 0°, ±22.5°, ±45°, ±67.5°, and 90° were prepared. The mechanical properties were characterized by quasi‐static tensile testing and also by dynamic mechanical analysis. The elastic modulus as a function of warp yarn orientation was modeled with the modified rule‐of‐mixture theory and with the theory of elasticity.

Colorimetric chitosan/polyvinyl alcohol composite membrane incorporated with anthocyanins as pH indicator for monitoring fish freshness

Nguyen,

Phung,

Nguyen

et al. 2024

During storage, food undergoes transformations, often producing volatile nitrogen compounds known as total volatile basic nitrogen (TVB‐N), which serves as an indicator of food freshness. In this study, chitosan (CTS) was blended with polyvinyl alcohol (PVA) and incorporated with anthocyanins (ACNs) to monitor the quality changes in fish fillets over different time intervals. The results demonstrated that the presence of PVA in the CTS membrane enhanced light transmittance and reduced water absorption due to the reinforcement of the membrane structure through chemical interactions. In the freshness monitoring experiments, the CTS/PVA membranes exhibited an improved value of total color difference (ΔE), facilitating better detection of pH changes of the surrounding environment. Moreover, the ΔE value of the CTS/PVA film was observed to be quite similar to the value at pH 9 after 24 h and at pH 11 after 36 h when the fish fillet was stored at 25°C. In contrast, the ΔE value of the CTS/PVA film closely matched the value at pH 11 after 96 h of storage at 4°C. Additionally, the correlation between the generated TVB‐N and the ΔE values indicated a higher correlation coefficient (R2) for the composite membranes compared to the pristine CTS or PVA membranes.