Despite the numerous advantages claimed by the NMMO process compared to the conventional cuprammonium and viscose processes, several concerns have been expressed on large-scale adoption of the NMMO process. The solvent (NMMO) itself is toxic and explosive by-products are generated during the process of dissolution. In addition, higher temperatures (>90 °C) and antioxidants are

The Lyocell process — Potential negative effects of side reactions

Fig. 18.6 Depiction of the possible side reactions of the NMMO process. Reproduced from [01Ros] with permission from Elsevier necessary for dissolution that could degrade cellulose. It has also been reported that it is difficult to recover the solvent after fiber production [01Ros]. In addition, the dissolution of cellulose in NMMO causes side reactions and also leads to the formation of considerable amounts of by-products that cause various unwanted properties in the fibers. Some of the side reactions of the NMMO system and their potential impacts are listed in Fig. 18.6. High temperatures (100-120 °C) required for dissolution also cause degradation of cellulose.

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