Physical structure characterization of high viscosity kenaf bast pulps

Abstract

The high viscosity kenaf bast pulps were prepared by using three different methods (A, B and C) and their viscosity values were 109,63 and 102 cP, respectively. The physical structures of these samples were characterized by FT-IR spectroscopy, X-ray diffractmetry and CP/MAS 13C NMR spectroscopy. Although the FT-IR spectra of all pulp samples revealed the similar chain conformation, the magnitude order of mean hydrogen bonding, relative ether linkage and crystallinity index were in the same trend with the order of viscosity values. Xray diffractograms and CP/MAS 13C NMR spectra indicated the presence of residual lignin between the (11̄0) plane of the pulp that subjected to the method B. However, FT-IR, X-ray and CP/MAS 13C NMR analyses showed the method A gives the highest crystallinity pulp. Furthermore, the relationships between the viscosity and the crystallinity index values in these three methods were in a high correlation (R > 0.9), that indicates the viscosity is parallel to the crsytallinity.