Mechanical properties of enzyme-treated chemically degummed corn husk fibers and their Weibull distributions
Fibers were extracted by chemical degumming various sections of corn husks and subjected to enzyme treating. The location of corn husks (outer, middle, inner) and the section of each corn husk (bottom, middle, upper) give 9 different sample sets, namely outer bottom, outer middle, outer upper; middle-bottom, middle-middle, middle-upper; inner-bottom, inner-middle, inner-upper. Linear density, diameter and tensile properties of the fibers are measured and analyzed statistically. Distributions of linear density (tex=g/km), force required to break single fibers(cN), elongation at break (%), breaking tenacity (MPa), elasticity modulus (GPa) complies well with two-parameter Weibull distributions. Husks were separated into three different types according to their location, namely, outer layer, middle layer and inner layer. Then those husks were cut into three different parts as upper, middle and bottom. Those 9 types of corn husk parts were digested separately in 0.2 M NaOH for 30 minutes at boiling temperature. The extracted fibers were washed 5 times with water. The fibers were neutralized with 10% acetic acid solution and rinsed again until pH 7 is attained. The obtained fibers were dried under ambient conditions before undergoing enzymatic treatment with Pulpzyme HC ®. The enzymatic treatments were carried out on fibers in beakers at 50°C for 60 min with a liquor ratio of 1:50 in distilled water. 2% xylanase enzyme concentration was calculated based on the percentage ratio of enzyme mass to the fiber mass. In order to stop enzymatic activity boiling water was poured on enzyme solutions. Then, the fibers were rinsed five times. Linear density, diameter, and mechanical properties, namely, breaking force, elongation at break, breaking tenacity and elasticity modulus of fibers were investigated. The fiber samples were conditioned at 21°C temperature and 65% relative humidity for a minimum of 24 hour-duration before the characterization processes. The linear density of corn husk fibers were determined according to ASTM D 1577-07. the mass of fibers in kg. Fiber diameter is calculated by: D=2*(tex/pi.rho) Mechanical properties of fibers were measured according to ASTM D 3822. The crosshead speed was 155 mm/min, the gauge length was 2.54 cm and the load cell was 10 N. 20 specimens for each sample fiber group were tested by using Tinius Olsen H10KT(R) Tester with QMat for Textiles(R) software.