Solid State 13C NMR and Diffuse Reflectance Mid-Infrared Spectroscopic Analysis of the Effects of Retting on the Chemical Composition of KenafFibre

Bast ribbons from Tainung 1 (T₁) and Guatemala 45 (G₄₅) cultivars of kenaf ( Hibiscus cannabinus ) were subjected to a chemical retting process. The resulting changes at the base and tip regions of each cultivar were analysed using solid-state ¹³C NMR and diffuse reflectance mid-infrared spectroscopies. Chemical retting was performed by boiling the substrates in NaOH (70 g litre⁻¹) +NaHSO₃ (5 g litre⁻¹) for 1 h, after which they were neutralised, washed and air dried. This process produced large decreases in the non-cellulosic components, though 25% of the phenolic component was left undegraded, and cellulose crystallinity was increased by ∽5% over that in unretted samples.