X hits on this document





6 / 17



Cellulose estimation

2 g of dewaxed and defatted sample was cut into small pieces. To this was added 100 ml of 3% sulphite solution, and then the mixture was filtered. The residue was washed in a beaker and made up to 100 ml with water, and 5ml of 1.78 % sodium chlorite (NaClO2) was added. After standing for 10 min, the fibre was filtered off and returned to the beaker, and the volume made up to 50 ml with water and 50 ml of 6% sodium sulphite. The entire mixture was boiled for 20 min, and the two previous steps were repeated. The material was suspended in 100 ml of water and 5 ml of hypochlorite with 2 ml of 20% sulphuric acid. The pH was adjusted to 4 with H2SO4. After incubating for 10 min and filtering, the residue was made up to 50 ml with water and 50 ml sulphite (to remove all lignins). The mixture was refluxed and boiled for 1 h, washed, filtered (G3 filter), and neutralized with NH3 solution. After washing well and drying, the total cellulose content was estimated as follows:

Total cellulose on dry basis = 100 x Residue / dry material weight


Physico-mechanical parameters

The processed and split culm strands (50 count dyed, 100 count dyed, 120 count dyed, and 120 count undyed) were analyzed for properties such as tex, actual strength, percent elongation, breaking force, and tenacity. The fibre samples were weighed, and their length was measured. The tex count (weight in g) was calculated using the following formula:

Tex count = wt (g) x 1000 /length (m)


Tenacity, elongation, and breaking force

Determination of the elongation percent and breaking force (Davies et al. 2007) was done by a modification according to the standard procedure followed at SITRA (South India Textiles Research Association) laboratories, Coimbatore, India, which was based on a constant rate of extension. The instrument (INSTRON Universal Strength Testing Installation INSTRON, 6021 series UK) was fitted with the pneumatic grip to hold the culm strands for the strength test. The top jaw was connected to the load cell. The cross head, on which the movable jaw was fixed, moves at a constant rate of extension. The specimen extends and finally breaks, which determines the end point of the test. The maximum force to break was recorded, while the extension or elongation of the specimen at Fmax was also noted as the breaking extension in %. From a series of tests using at least 25 culm strands, the mean breaking strength (actual strength) and the mean breaking elongation percent was calculated. The (Coefficient of variance) CV% of strength and elongation was also calculated. The tenacity was calculated using the

following formula:

Tenacity = Breaking strength (g) / (Tex/denier)


Statistical analysis was done using data on fibre dimension of the rind and core regions. The arithmetic mean and standard deviation (SD) were determined. Student’s ‘t’

Benazir et al. (2010). “Sedge fibers and strands,” BioResources 5(2), 951-967.


Document info
Document views54
Page views54
Page last viewedThu Jan 19 07:28:15 UTC 2017