GREENCO - Untapping the potential of GREEN COmposites by combining performance and environmental sustainability

Abstract:

The push towards more and more sustainable materials has given a strong impulse to research in the field of the so-called “green polymer composites”, namely composite materials made of a biodegradable polymer matrix filled with natural fibers. To date, the scientific community has mainly focused on the maximization of the performance of composites based on apparently sustainable raw materials. Despite some notable results, the actual “greenness” of such systems remains questionable. Pristine natural fibers generally require highly impacting pre-treatments to enhance fiber dispersibility and quality of the fiber-matrix interphase. Regarding the matrices, many bio-based and/or bioderived polymers are only marginally less impacting than many petroleum-based plastics. Moreover, the actual biodegradability of most green matrices is far from being proved. This calls into question the key-property that a truly sustainable green composite should possess, i.e., the possibility to degrade in a reasonable time if dispersed in the environment. GREENCO addresses these crucial issues by focusing on the role of the natural fibers, which, in addition to providing reinforcing action, can be engineered to ensure pro-degradative effect and reduce the overall carbon footprint. Owing to the complementary expertise of a close-knit research team, the challenge will be addressed at different level, from the rational selection of the raw materials (polymers and fibers) to their convenient pre-treatment(s) (e.g., enzymatic, microwave), up to the optimization of formulations that combine the unescapable features for large scale applications: adequate mechanical properties and genuine environmental sustainability. A systematic Design of Experiments is planned for elucidating the complex relationships between the multiple input variables (cellulose content of the fibers, surface treatment(s), fiber content) and the key output variables (mechanical properties, rheological behavior, biodegradability). Moreover, each step of GREENCO will be driven by the quantitative analysis of the environmental impact of materials and processes based on Life Cycle Assessment. GREENCO also aims at changing the approach towards green composites, whose performance can no longer be separated from their actual sustainability. This will be done by introducing a novel design principle grounded on the concept of “sustainability-weighed performance”, according to which lower performance can be accepted provided that sufficient environmental benefits are eventually achieved. Such an approach will be highly beneficial to the next generation of materials scientists/engineers, who will play a leading role in GREENCO.