Cellulosic fibers were extracted from Alfa stems (Stipa tenaccissima L.) using alkaline methods only and without any fiber pretreatment in order to reduce the environmental impact and the extraction costs. A simple post-treatment that consisted of subsequent manual fiber disintegration was studied. The extraction quality was improved according to a two-step investigation. Firstly, the processing temperature, duration and the sodium hydroxide (NaOH) concentration, together with the usefulness of the post-treatment, were studied based on visual examinations. Then, a second set of NaOH concentrations was selected and their effect on the non-cellulosic components removal and on the crystallinity degree of the native crystalline cellulose I was studied. Fibers were characterized by means of Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD), High Performance Anion Exchange Chromatography equipped with Pulse Amperometric Detection (HPAEC-PAD), together with optical microscopy and Scanning Electron Microscopy (SEM). It was shown that the best pulp was obtained by treating the stems in a NaOH solution with a concentration of 3.25 M at 100 °C during 2.5 hours, together with applying the post-treatment. The resulting pulp consisted mainly of single fibers with a smaller amount of bundles and nano-fibrillated cellulose (NFC). Besides, the crystallinity of cellulose I was of 88% and the fibers had an average diameter and length of 10.19 µm and 1082 µm, respectively. Furthermore, the XRD study showed that treating the fibers with NaOH concentrations beyond 3.25 M resulted in a significant drop in the cellulose I crystallinity.
|Julkaisu||Cellulose Chemistry and Technology|
|Tila||Julkaistu - 1 tammikuuta 2018|
|OKM-julkaisutyyppi||A1 Julkaistu artikkeli, soviteltu|