Production and Characterization of Pulp from Flax Straw

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Addis Ababa University


Flax (Linum usitatissimum) is a bast fiber plant, it has a long length of fiber and good sources of pulp used as input for the production of paper. Pulping of flax straw with Kraft process was studied. Proximate analysis, Chemical compositions, and morphological properties of flax straw fibres were also investigated in this paper. Proximate analysis including ash content (4.13%) and moisture content (11%). Chemical properties including cellulose (51.34%), hemicellulose (25.20%), lignin (14.12%), ash (4.13%) and extractives (5.21%) were determined by assuming flax straw content have only the above compositions. Morphological properties of flax straw including fiber length, diameter, lumen width, and cell wall thickness was 1.41mm, 16.78μm, 9.45, and 3.77μm, respectively. Flax straw has an acceptable Runkel ratio (0.8) and flexibility coefficient (56.32) in the range of non-woods. Morphological analysis of pulp from flax straw by using a scanning electron microscope(SEM) to determine the morphology of fiber. Basic understanding from this results in qualitative determination the structure of fiber even if see the fiber have a crack or not. The quality and length of pulp directly related to the strength and properties of the paper. Pulp production from flax straw including Various pulping conditions including the composition of cooking liquor (10, 15 and 20%) and cooking temperature (130, 140 and 150oC) at reaction times (60, 90 and 120 min) were studied in full-factorial design and determine the good pulping conditions. The influence of pulping conditions on the pulp obtained (Yield and Kappa number) are analyzed by three-factor and full factorial experimental design, and optimum pulping conditions are obtained. The best properties of the pulp kappa number and yield were obtained with 10% sodium hydroxide, in the cooking solvent, 131.74oC cooking temperature and 120 min as cooking time. The optimum value of yield and kappa number were obtained from experiment 40.56%, 10.45 respectively. Tensile strength, tearing strength and burst strength are fit on the standard. In general, results based on chemical and morphological analysis indicated that flax straw fibres are promising fibrous raw material for paper production.



Flax Straw, Pulp, Paper, Kraft Pulping, Full Factorial Design