Age-induced changes in cellulose nanostructure of cotton textiles studied by combined scattering and modeling

Age-induced changes in the structure and properties of polymer materials are highly relevant in various contexts, from paper and textile recycling to marine pollution and preservation of cultural heritage. In particular, the recycling of common cellulosic textiles such as cotton fabrics would greatly benefit from a better understanding of these changes and methods to study them efficiently. Based on our previous work [1], we aim to develop a high-throughput method for characterising the age-induced degradation of cotton fibers, based on near infra-red (NIR) spectroscopy and machine learning. To address the nanoscale mechanisms of the degradation and to form a link to different experimentally observable properties, we utilize the combination of X-ray scattering and molecular modeling [2].

We conduct systematic X-ray scattering experiments on cotton textiles with different degrees of degradation induced by chemical treatments and laundering. We aim to detect changes in the crystalline structure and crystallinity by wide-angle X-ray scattering (WAXS) and differences in the arrangement of cellulose microfibrils with small-angle X-ray scattering (SAXS). Possible degradation mechanisms will be modeled using a combination of stochastic and dynamic molecular simulations. The models will be linked to the experimental scattering results through scattering intensities computed from the models [3]. The results will serve as a basis for the NIR based characterization method and elucidate the mechanisms of structure and property changes in cotton textiles during their use, supporting their efficient recycling.

[1] Mahlamäki, E.; Schlapp-Hackl, I.; Rissanen, M.; Hummel, M.; Mäkelä, M., Resour. Conserv. Recycl. 2023, 193, 106984
[2] Paajanen, A.; Zitting, A.; Rautkari, L.; Ketoja, J; Penttilä, P., Nano Lett. 2022, 22, 5143
[3] Penttilä, P.; Paajanen, A.; Ketoja, J., Carbohydr. Polym. 2021, 251, 117064