Page 80 - Basic Principles of Textile Coloration

HO OH + OCN CH3 REFERENCES 69
Polyether or polyester C
CH3 NCO
Diisocyanate

OCN CH3 NHCOO OCONH CH3 NCO
C C
CH3 CH3

Urethane link

NH2CH2CH2NH2

NHCOO CH3 U Urethane link
OCONH C
CH3 CH3
C NHCOO
CH3

U NHCONHCH2CH2NHCONH
(Urea link)

Figure 4.9 Formation of a segmented polyurethane

capable of strong inter-chain hydrogen bonding and provide the strong rigid
segments of the matrix. On initial stretching, the flexible coiled segments of the
polyester or polyether uncoil, but the bonded urethane segments remain immobile.
On releasing the stress, the flexible chains recoil, and since the rigid segments have
not permitted any extensive chain slippage, the flexible chains return to their
original positions. Since they have amino end groups derived from the diamine, the
dyeing of segmented polyurethane fibres is similar to that of the nylons.

REFERENCES

1. J P O’Brian and A P Aneja, Rev. Prog. Coloration, 29 (1999) 1.
2. C Hwo, et al., Chemical Fibers International, 50 (1) (2000) 53.
3. AATCC Int. Conf. and Exibition (1993) 308.