worksheet and assessment card masters - National STEM Centre

Fabric can be treated with a resin finish. Find out its
effects for yourself.
The treatment used to give minimum-iron, drip-dry
performance to cotton -involves the production ofa
cross·:linkedpolymer (resin).withinthe fabric structure.
The simplest system involves urea and formaldehyde.
--A-B-A-B-A-B-
I I I
B
I --A--B--A-
B
I
B
I B--A -B-
This resin finish ,givento cotton fabrics improves the
easy-care properties of the fabric, but this is not the
only effect on the fabric.
YOU WI LL NEED:
Samples of untreated and drip-dry cotton
Ironing facilities
Select white cotton fabrics of comparable quality - one
untreated and the other treated with a drip-dry finish.
Carry out the following tests: tear resistance, creasing,
and pleat retention (see sections 7.5 and 12.5 or ask
your teacher for help). Record your results. Does it come out?
Will it
tear easily?
Will it
crease?
Will it
hold a pleat?
Untreated cotton Drip-dry cotton
CAN YOU BLEACH WHITE COTTON WHEN IT HAS
A RESIN FINISH?
YOU WI LL NEED: .
White drip-dry cotton (old shirt fabric will do), 2 pieces,
10 cm X 10 cm
White calico (untreated), 2 pieces, 10 cm x 10 cm
Ribena or fresh blackcurrant or blackberry juice
Chlorine bleach (e.g. Parazone, Domestos)
Access to washing and ironing facilities
1 Stain one piece of each type of fabric with fruit juice.
Let it dry in. Keep the other piece of each fabric as a
control.
heavy stain
2 W'asheach stained fabric to try to remove the stain.
3 Bleach out the stain.
shadow stain
Follow the instruction on the bottle of bleach
carefully.
no stain
4 Thoroughly rinse the fabrics and dry them.
5 Iron each fabric with a hot iron (cotton setting).
c
hot setting
Describe the appearance of each piece of fabric.
© 1984 Nuffield-Chelsea Curriculum Trust