The objective of this study was to identify chitosan formulations suitable for sustainable functional integration into composite materials. To this end, the influence of solvent type (acetic acid and lactic acid) and chitosan molecular weight on film formation, rheological behavior, thermal response, thermo-optical properties, chemical structure, and piezoelectric performance was systematically investigated. Optimized casting and drying procedures produced transparent, homogeneous, and mechanically stable films suitable for comprehensive characterization. Rheological and thermo-optical analyses demonstrated that solvent selection strongly influenced polymer network formation and molecular mobility. Films prepared using acetic acid exhibited denser and stiffer polymer networks with improved dimensional stability, whereas lactic acid produced more flexible and elastic films. Thermogravimetric analysis revealed only minor differences in the intrinsic thermal stability of the investigated films, while FTIR confirmed that the solvent systems did not alter the chemical structure of chitosan. Electrical measurements carried out whilst the system was subjected to periodic mechanical excitation revealed weak but equally periodic electrical signals, which demonstrate a sensor functionality. These results demonstrate that chitosan films possess tunable structural, thermal, and potential mechanoelectrical sensor properties and highlight their potential as sustainable, functionally integrated components in composite material systems.

The development of sustainable functional materials is an important step toward resource-efficient and smart food production. Insects represent a promising renewable source of chitin, which can be further converted into chitosan and processed into materials with versatile mechanical, chemical, and functional properties. This work focuses on the development of insect-derived chitin and chitosan as functional materials for piezoelectric sensing elements and their subsequent integration into composite structures. The investigated material pathway begins with the extraction and purification of chitin from insect biomass, followed by its controlled conversion into chitosan. Particular attention is given to the influence of extraction, deacetylation, and processing conditions on the resulting material properties. Chitin and chitosan are subsequently processed into films and composite structures and investigated regarding their morphology, mechanical behavior, stability, and electromechanical response. A central objective is the development of bio-based materials capable of generating an electrical response under mechanical deformation, pressure, or vibration. The intrinsic properties of chitin and chitosan, as well as their combination with additional functional phases, provide opportunities to tailor the piezoelectric performance and mechanical characteristics of the resulting materials. The developed sensing materials are further considered for incorporation into composite structures, where mechanical and sensing functions can be combined within a single material system.

Plastic pollution is known to impact the biophysical characteristics of soil. However, there is currently limited knowledge regarding the sequence of events that occur at the foundational levels of terrestrial ecosystems. This encompasses changes in the abiotic properties of soil and their subsequent effects on various aspects of soil-plant interactions, including soil microbial communities and plant characteristics. This study aims to investigate the influence of four different types of plastic pellets - polylactic acid (PLA), polyamide six (PA6), polypropylene (PP), and polystyrene (PS) - on various indicators that reflect soil quality, as well as the growth and development of mangold (Beta vulgaris var. cicla). The study found that the presence of plastic pellets in soil led to significant changes in various parameters, such as the biomass of the plants, the elemental composition of tissues, and root characteristics. The biomass of the plants was reduced in the presence of plastic pellets, indicating that plastic pollution in soil can have a negative impact on plant growth and development. The elemental composition of tissues was found to be altered, which could potentially affect the nutritional quality of the crops. The study revealed changes in root characteristics, which can have implications for nutrient uptake and water absorption.