The Interaction Between CO₂ and NaOH-Dissolved Cellulose as a Potential in Cellulose Technology

The growing awareness of consumers, governments, and industries on their influence on the environment generated the world trend to search for solutions to mitigating climate change. Perhaps the most popular subject refers to carbon dioxide capture and applications of green resources for this reason. From the perspective of renewable and sustainable materials, it is hard to think about better candidates than biopolymers. Over the past few years, a lot of attention has been given to understanding the mechanism of action between various saccharides and CO₂; yet the most abundant of them all, cellulose, remained in the shadow of investigations. The reason behind this low interest could be the perception of cellulose as a difficult to process, with applications more related to the paper, textile, or packaging industry. However, in our study, we present that cellulose exhibit a strong affinity for alkali-dissolved CO₂ that leads to coagulation of polymer and formation of novel material with a perspective for industrial applications.<br/>Here, we take the control over the gas delivery and conclusively study the effect of CO₂ on cellulose dissolved in NaOH at two different temperatures (25 and 5 °C). The <i>in-situ </i>analysis gives an inside to carbonation (cellulose <i>vs </i>inorganic species), changes in temperature and pH. It allows hypothesising on the initial mechanism of interaction between cellulose and CO₂ that results in polymer coagulant. Furthermore, the created coagulants, analyse from the perspective of structural and crystallinity changes, prove competitive to alcohol precipitates. This opens for the employment of CO₂ in the process of cellulose regeneration. Our findings are presented with the implication for cellulose processability, in the context of cellulose derivatives and regenerated fibres production, as well as effective exploitation of CO₂ gas.