Extraction and Characterization of Bast Fibres from Roselle (Hibiscus sabdariffa) Stem for Industrial Application

Abstract

Fibers extracted from Roselle (Hibiscus sabdariffa) stem were investigated as starting raw materials for textile industries, bio-packaging material, pulp and paper products, particle boards and composite material applications. Two extraction methods for obtaining bast fibres from Hibiscus sabdariffa stem such as Bacterial retting (BR) method and chemical retting (CR) method were studied. The Physico-chemical and mechanical properties of Bacterial retted (BR) and chemically retted (CR) Roselle (Hibiscus sabdariffa) fibre was Light brown in colour, with 16.07-20.2 Diameter(μm), 2.10-2.8 Fibre length (mm), 9.54-11.00% Moisture, 0.93-2.50% Ash, 55.55-60.40% Cellulose, 33.70-27.04% Hemicellulose, 10.50-11.40% Lignin, 145.60-177.55 MPa Strength, 20.70-24.90 GPa Modulus, 0.5-0.7% Elongation at break for bacterial retting (BR) method while chemical retting (CR) method was Dark brown in colour, 16.07-20.2 Diameter(μm), 2.10-2.8 Fibre length(mm) 12.90-14.50% Moisture, 1.00-2.70% Ash, 48.56-56.62% Cellulose, 38.07-31.85% Hemicellulose, 12.50-11.64% Lignin, 135.15-159.05MPa strength, 19.85-23.70GPa, 0.4-0.6% Elongation at break. The results showed that fibres produced by bacterial retting (BR) has better quality than chemical retting (CR) in terms of mechanical properties and flexibility, but the time involved in bacterial retting (BR) was too long to be considered for today’s industrial process integration, thus making it less attractive. More advancement in biotechnology with combined enzymatic and chemically retting will give shorter time with high quality fibres. In general, bast fibres from Roselle (Hibiscus sabdariffa) stem is also a unique natural fiber in the class of jute and kenaf. R&D into large scale production and industrial utilization of indigenous bast fibres will no doubt aid the revival and future development of Nigerian textile and allied industries.