| Abstract:The cotton pulps pretreated with PFI refining, dimethyl sulfoxide(DMSO), 4% sodium hydroxide respectively and without any pretreatment were used as raw material to prepare the cellulose nanocrystals(CNCs) by acid hydrolysis. The properties of the CNCs were characterized by scanning electronic microscope(SEM), X-ray diffraction(XRD), infrared spectrum(IR) and thermogravimetric analysis (TG). The observation of SEM indicated that the CNCs prepared with by the first 3 pretreated cotton pulps had rod-like shape, the length was 200～400 nanometers and the diameter was about dozens of nanometers. But the CNCs prepared with NaOH pretreated cotton pulp had spherical shape and remarkable flocculation, the diameter was about 100 nanometers. XRD results indicated that the CNCs had the same crystal type as cotton pulp and the crystallinity of CNCs was improved. IR spectroscopic analysis demonstrated that the CNCs had the same functional groups as cotton pulp. TG analysis of the CNCs showed that the thermal stability of CNCs was worse than that of cotton pulp. But surprisingly the CNCs using NaOH pretreated cotton pulp as raw material had the largest residual quantity up to 40% at 600℃, the reason of this unordinary result remains to be explained in further study. |
