Compare the tensile strength of dry and wet cotton yarns by lea method and calculate their CLSP.

Abstract:

The strength along the length of a body is known as its tensile strength also called linear strength of that body. In the textile fibers or yarns only tensile strength is calculated due to high length to width ratio of the textile materials. The tensile strength values of the dry and wet cotton yarns varies very much from each other. The strength of wet cotton yarns is greater than that of dry cotton yarns. This is due to the formation of hydrogen bonds between the water molecules and the hydroxyl groups in the cellulosic rings of the cotton fibers in the wet state. There is one phenomenon known to stand that when the cotton gets wet its crystalline region increases hence the strength of the fibrous structure increases.

Objectives:

• To calculate the tensile strength of cotton yarns in both dry and wet state.
• To calculate CLSP of dry cotton yarns.
• To compare the tensile strength of dry and wet cotton yarns.

Materials:

• Dry cotton yarn.
• Water
• Beaker
• Wrapping Reel
• Tensile Strength Testing Machine
• Weighing Balance

Procedure:

• Dry cotton yarn was taken.
• 8 leas of 120 yards of that yarn were made using the wrapping reel.
• 4 of them were soaked in the water placed in the beaker.
• Weight of each of the dry samples were taken on the weighing balance.
• These were now placed on the tensile strength testing machine.
• Tensile strength of both dry and wet yarns were calculated.

Calculations:

Length of lea taken = 120 yards

120 yards = 10920 cm

English count = 0.0059 x  (length of cm / weight in grams )

CLSP = Count Lea Strength Product = Count x Tensile Strength

Dry Yarn

Sample #	Tensile Strength (Kg)	Tensile Strength (lbs.)	Weight (grams)	Count (Ne)	CLSP
1	33	72.6	3.06	20.055	1455.993
2	36	79.2	3.14	20.518	1625.025
3	42	92.4	3.19	20.19	1865.55
4	40	88	3.22	20.008	1760.704
Average Values	37.75	83.05	12.61	20.193	1676.815

 

Wet Yarn

Sample #	Tensile Strength (Kg)	Tensile Strength (lbs.)
5	48	105.6
6	46	101.2
7	58	127.6
8	55	121
Average Values	51.75	113.85

 

Results:

Average Tensile Strength of Dry Cotton Yarns = 83.05 lbs.

Average Tensile Strength of Wet Cotton Yarns = 113.85 lbs.

% difference in Strength of dry and wet cotton yarns = 27%

Normal range = 10-15 % (According to ASTM standards)

CLSP values of Dry cotton yarns = 1676.81