Periodate oxidation of cellulose to produce "dialdehyde cellulose" (DAC) has lately received increasing attention in sustainable materials development. Despite the longstanding research interest and numerous reported studies, there is still an enormous variation in the proposed preparation and work-up protocols. This apparently reduces comparability and causes reproducibility problems in DAC research. Two simple but prevalent work-up protocols, namely glycol quenching and filtration/washing, were critically examined and compared, resulting in this cautionary note. Various analytical techniques were applied to quantify residual iodine species and organic contaminations from quenching side reactions. The commonly practiced glycol addition cannot remove all oxidising iodine compounds. Both glycol and the formed formaldehyde are incorporated into DAC's polymeric structure. Quenching of excess periodate with glycol can thus clearly be discouraged. Instead, simple washing protocols are recommended which do not bear the risk of side reactions with organic contaminants. While simple washing was sufficient for mildly oxidised celluloses, higher oxidised samples were more likely to trap residual (per)iodate, as determined by thiosulfate titration. For work-up, simple washing with water is proposed while determining potential iodine contaminations after washing with a simple colorimetric test and, if needed, removal of residual periodate by washing with an aqueous sodium thiosulfate solution.

The potential of biobased materials like regenerated celluloses as precursors for carbon fibers (CFs) is long known. However, owing to an intrinsic two pathway pyrolysis mechanism of cellulose its carbonization is accompanied with side reactions under generation of volatiles. In practice, this leads to a reduced char yield, results in inferior mechanical properties of the CFs, and requires time-consuming thermostabilization procedures or wet-chemical pretreatments during production. Thus, their market share currently remains low. In ambitions to circumvent these issues, the potential of electron beam irradiation (EBI) as a dry chemical pretreatment for cellulosic CFs was investigated in this study. The conducted chemical analyses showed that high radiation dosages (2 MGy) lead to a strong depolymerization of the cellulose chains down to oligomers , while the fibrous macrostructure was preserved. Minor oxidation reactions were also evident. Thorough thermostabilization experiments under air in the temperature range from 100 °C to 250 °C revealed that reactions caused by EBI treatment alone were insufficient to increase the char yield. Only when the EBI treated precursor fibers are subjected to heating between 200 and 250 °C the char yield increased significantly to 34.4 % compared to 12.1 % for the untreated fiber. Furthermore, the EBI treatment strongly accelerated the reactions during thermostabilization allowing to collect CFs at heating rates of 2 °C/min compared to 0.5 °C/min needed for pristine fibers. Additionally, cellulose-lignin composite fibers were subjected to EBI treatment, proving that this strategy can also be applied to these emerging biobased CF precursors.