Polymers Question Paper chromatograms were developed for 50:50 blends of nylon-6
ID: 490648 • Letter: P
Question
Polymers Question
Paper chromatograms were developed for 50:50 blends of nylon-6,6 and nylon-6,1O after the
mixture had been heated to 290°C for various periods of time.t The following observations
describe the chromatograms after the indicated times of heating:
o h-two spots with Rf values of individual polymers.
1/4 h-two distinct spots, but closer together than those of 0 h.
1/2 h-spots are linked together.
3/4 h-one long, diffuse spot.
11/2 h--one compact spot, intermediate Rf value.
On the basis of these observations, criticize or defend the following proposition: the fact that
the separate spots fuse into a single spot of intermediate Rf value proves that block copolymers
form between the two species within the blend upon heating.
Explanation / Answer
Nylon-6,6 and Nylon 6,10 are prepared from nylon salt by heating. Nylon salt is obtained from neutralisation reaction between diacid and diamine. Nylon salt undergoes step growth condensation by elimination of water molecules. So when we heat 50:50 blends of nylon-6,6 and nylon-6,10, we expect that two polymers will combine to form block copolymers.