DETERMINATION OF COTTON/NYLON BLEND
PROCEDURES:
STEP 1: FROM THE SAMPLE, CUT A TEST SPECIMEN OF ABOUT 2 GM. DETERMINE ITS
OVEN DRY MASS BY PUTTING ON A CONDITIONING CABINET AT ABOUT 105±3 DEG CENTRIGRADE
FOR 3 HOURS
STEP 2: CUT THE REPRESENTATIVE SAMPLE INTO SMALL PIECES APPROXIMATELY 25MM
IN LENGTH.
STEP 3: PUT ALL THE PIECES INTO A BEAKER AND ADD 200ML OF 80 PERCENT
FORMIC ACID TO IT. SHAKE THE CONTENTS OF THE BEAKER VIGOROUSLY AT INTERVALS FOR
15 MINUTES.
STEP 4: DECANT THE LIQUID THROUGH A NYLON FILTER CRUCIBLE. ADD MORE FORMIC
ACID TO THE BEAKER. SHAKE THE CONTENTS FOR A FEW MINUTES, TRANSFER THE SOLUTION
AND THE RESIDUE INTO THE NYLON FILTER CRUCIBLE.
STEP 6: WASH OUT ANY REMAINING FIBRES IN THE FLASK WITH MORE FORMIC ACID
AND FILTER THE WASHINGS THROUGH THE NYLON FILTER CRUCIBLE. WASH THE RESIDUE
SUCCESSIVELY WITH FORMIC ACID, HOT DISTILLED WATER, AMMONIA AND COLD DISTILLED
WATER
STEP 7: DRY THE RESIDUE AT 105-110 DEG CENTRIGRADE IN THE CONDITIONING
CABINET AND DETERMINE ITS OVEN DRY MASS
CALCULATIONS:
W=
OVEN DRY WEIGHT OF THE SAMPLE
F
= OVEN DRY WEIGHT OF THE RESIDUE
P
= PERCENTAGE BY WEIGHT OF NYLON FIBRE
= (W– F) X 100
W
P’ = PERCENTAGE BY WEIGHT OF COTTON FIBRE
= 100 - P
