DETERMINATION OF POLYESTER/COTTON
BLEND:
PROCEDURES:
STEP1: PREPARE ACID MIXTURE BY MIXING 70ML OF DISTILLED WATER WITH 200ML
OF ACETIC ACID AND BY ADDING CAREFULLY WITH COOLING 190ML OF SULPHURIC ACID IN
SMALL LOTS. THE MIXTURE IS ALLOWED TO COOL TO THE ROOM TEMPERATURE
STEP 2: FROM THE TEST SAMPLE, DRAW A REPRESENTATIVE SAMPLE WEIGHING ABOUT
2GM
STEP 3: CUT THE TEST SPECIMEN INTO PIECES OF APPROXIMATELY 25MM IN LENGTH
STEP 4: PUT THE SAMPLE ON CONDITIONING CABINET AT 105±3 DEG FOR 3 HOURS,
COOL IT AND DETERMINE ITS OVEN-DRY WEIGHT
STEP 5: PUT ALL THE PIECES INTO A GLASS BEAKER AND ADD 100ML OF ACID
MIXTURE TO IT
STEP 6: MAINTAIN THE CONTENTS IN THE BEAKER AT ABOUT 50DEG FOR ONE HOUR, SHAKING THE BEAKER GENTLY AT INTERVALS OF 10 MINUTES
STEP 8. FILTER THE CONTENTS THROUGH A NYLON FILTER CRUCIBLE.
TRANSFER ANY RESIDUAL FIBRES FROM THE BEAKER WITH LITTLE ACID MIXTURE INTO THE
CRUCIBLE
STEP 9: WASH THE RESIDUE ON THE FILTER ONCE BY FILLING THE CRUCIBLE WITH
ACID MIXTURE
STEP 10: WASH THE RESIDUE SUCCESSIVELY SEVERAL TIMES WITH COLD WATER, TWICE
WITH DILUTE AMMONIA SOLUTION AND THEN THOROUGHLY WITH COLD WATER
STEP 11: DRY THE CRUCIBLE AT 105±3 DEG CENTRIGRADE FOR ONE HOUR IN THE
CONDITIONING CABINET
STEP 12: WEIGH THE RESIDUE ON THE SENSITIVE ELECTRONIC BALANCE
CALCULATION:
F
= OVEN DRY WEIGHT OF THE RESIDUE
W= OVEN DRY WEIGHT OF THE TEST
SPECIMEN
P
= PERCENTAGE BY WEIGHT OF POLYESTER
= F X 100
W
P’=
PERCENTAGE BY WEIGHT OF COTTON
= 100 - P
