Cotton fiber maturity determination using the Sodium Hydroxide swelling method.
IS 236: 1968 ,ASTM D1442-00
- Fiber maturity ratio
- Fiber maturity coefficient
Instruments Used For Testing
Microscope, Glass slides, and cover slips, Scissors, forceps, glass rod, 18 percent Sodium hydroxide solution, draw box.
Working Principle Of Instrument
Approximately 100 fibers are placed between slits and viewed under a projection microscope. The fibers are carefully spread in the glass slides, covered with another glass slide after adding a drop of sodium hydroxide. This causes swelling of fibers to give a better appearance.
Specifications Of The Instrument
- Observation screen : 200mm
- Graduated screen
- Coaxial halogen lamp
- Mechanical stage of size: 135* 120mm
- Magnification : 125X to 1000X
Radial projection microscope is a versatile instrument of universal application designed for all stages of textile production. It is compact, dust proof and light weight. The test object projected on the screen in desired magnification can be analyzed. Adjustments require very few operations so that the user is free to concentrate on the image on the screen.
- Vertical adjustments
- horizontal adjustments
- The fibers are opened and cleaned. The tuft is prepared from which the sample is to be tested.
- 18% caustic soda solution is also prepared which is used to swell the fibers.
100 – 200 fibers approximately.
- 100 – 200 fibers are removed approximately from the bundle in their lengthwise direction.
- The fibers are placed on a microscope slide and spread carefully to a width of 30mm to 40mm.
- A drop of mounting medium ie sodium hydroxide is placed and covered with another glass plate.
- This 18% caustic soda spreads without any air bubbles and causes swelling of fibers.
- The presence/ absence of convolutions is observed by placing the slide in the microscope.
- Mature fibers have a well-developed cell wall and appear rod-like after swelling.
- Immature fibers are ribbon-like with convolutions.
- Half mature fiber lies between these two classes.
- The number of mature, half mature and immature fibers are counted and calculations are performed.
|S.NO||Total Number of Fibers||Mature
- Percentage of mature fibres (PM) = (M ÷ t) × 100
Where, M = total number of mature fibers,
and t = total number of observations.
- Percentage of half-mature fibers =(H ÷ t) × 100
- Percentage of immature fibers =(I ÷ t) × 10
where M, H, I are no.of mature, no.of half mature, no.immature fibers.
- maturity ratio MR = (N-D/200) + 0.7
N – Percentage of normal fibers
P – Percentage of dead fibers
- Maturity coefficient MC = (M+0.6(H)+ 0.4(I) )/ 100
M – Percentage of mature fibers
I – Percentage of immature fibers
H – Percentage of half-mature fibers
Statistical Tools/Parameters Used
Mean, C, t-test, f-test.
Modern Instruments Available To Test These Properties/Parameters
Fiber length and Strength-HVI.
Uses Of This Test
For testing cotton sample for suitability for spinning a count for finding FQI value of the cotton sample.