Östlund Å, Idström A, Olsson C et al (2013) Modification of crystallinity and pore size distribution in coagulated cellulose films. Oktaviani NA, Matsugami A, Hayashi F, Numata K (2019) Ion effects on the conformation and dynamics of repetitive domains of a spider silk protein: implications for solubility and β-sheet formation. Okano T, Sarko A (1985) Intermediates and a possible mercerization mechanism. O’sullvian AC (1997) Cellulose: the structure slowly unravels. Crystal and molecular structure of Na-cellulose I. Nishimura H, Okano T, Sarko A (1991) Mercerization of cellulose. Massiot D, Fayon F, Capron M et al (2002) Modelling one- and two-dimensional solid-state NMR spectra. Liu Z, Sun X, Hao M et al (2015) Preparation and characterization of regenerated cellulose from ionic liquid using different methods. Larsson PT, Wickholm K, Iversen T (1997) A CP/MAS 13 C NMR investigation of molecular ordering in celluloses. Langan P, Nishiyama Y, Chanzy H (2001) X-ray structure of mercerized cellulose II at 1 Å resolution. Kontturi E, Meriluoto A, Penttilä PA et al (2016) Degradation and crystallization of cellulose in hydrogen chloride vapor for high-yield isolation of cellulose nanocrystals. Kono H, Numata Y, Erata T, Takai M (2004) 13C and1H resonance assignment of mercerized cellulose II by two-dimensional MAS NMR spectroscopies. Kobayashi K, Kimura S, Togawa E, Wada M (2011) Crystal transition from Na-cellulose IV to cellulose II monitored using synchrotron X-ray diffraction. Kirui A, Ling Z, Kang X et al (2019) Atomic resolution of cotton cellulose structure enabled by dynamic nuclear polarization solid-state NMR. Isobe N, Kim UJ, Kimura S et al (2011) Internal surface polarity of regenerated cellulose gel depends on the species used as coagulant.
Idström A, Schantz S, Sundberg J et al (2016) 13C NMR assignments of regenerated cellulose from solid-state 2D NMR spectroscopy. Horii F, Hirai A, Kitamaru R (1983) Solid-state 13C-NMR study of conformations of oligosaccharides and cellulose - Conformation of CH2OH group about the exo-cyclic C-C bond. (01)00025-9įrench AD, Santiago Cintrón M (2013) Cellulose polymorphy, crystallite size, and the Segal Crystallinity Index. (02)00132-5įink HP, Weigel P, Purz HJ, Ganster J (2001) Structure formation of regenerated cellulose materials from NMMO-solutions. Ĭolom X, Carrillo F (2002) Crystallinity changes in lyocell and viscose-type fibres by caustic treatment. Ĭhang C, Duan B, Zhang L (2009) Fabrication and characterization of novel macroporous cellulose-alginate hydrogels. Graphic abstractĪzubuike CP, Rodríguez H, Okhamafe AO, Rogers RD (2012) Physicochemical properties of maize cob cellulose powders reconstituted from ionic liquid solution. Moreover, the neutralization, which was conducted after the alkaline treatment with H 2SO 4, established the most suitable conditions for the crystallization of cellulose II.
During the NaOH treatment, at a concentration of 10%, the crystallinity index evaluated by both NMR and X-ray was maximized further, at the treatment temperature of 80 ☌ the crystallinity of the cellulose II evaluated by NMR improved. It is believed that the selective Na-cellulose construction in the inaccessible surface cellulose is the result of an increase in the size of cellulose II crystals. NMR spectroscopy of the intermediate state of the NaOH detected the partial generation of Na-cellulose further, another domain exhibited the spectrum of highly crystallized cellulose II.
It can be thought that controlling the partial Na-cellulose construction is important for improving the assembly of cellulose II this is achieved by optimizing the concentration of NaOH, treatment temperature, and selection of acid for neutralization. Subsequently, neutralization was performed for the crystallization of cellulose II and the effects of the acid employed were also evaluated. The variations in rate of each component were monitored at different NaOH concentrations and reaction temperatures during the treatment these components include the crystalline and accessible surface as well as the inaccessible surface/amorphous region. The cellulose employed was originally filter paper from wood pulp that was subsequently mercerized or dissolved and regenerated to create partly crystalline cellulose II. These post-treatments used different temperatures, lower concentrations of NaOH than used in, for example, the original mercerization, and different neutralization methods. The study incorporated post-treatments of samples that had been mercerized or regenerated to yield somewhat crystalline cellulose II. In this study, methods of completing the structural conversion of partly crystalline cellulose II were studied by solid-state 13C CP/MAS NMR spectroscopy and X-ray diffraction.
0 kommentar(er)
