Page 414 - Handbook of Properties of Textile and Technical Fibres

The chemistry, manufacture, and tensile behavior of polyamide fibers 387

Cl
3+
N Cl O Ga Cl N
3+
O Ga Cl N Cl O
Cl

Cl
3+
N Cl Ga O Cl 3+ N
O N Cl Ga O
Cl
Cl

Cl
3+
N 3+ Cl O Ga Cl N
O Ga Cl N O
Cl
Cl
Figure 12.20 Replacement of hydrogen bonds in polyamides by GaCl 3 .

using a high molecular-weight polymer, provide initial moduli up to 13 Gpa, which is
twice the initial moduli of 6 GPa for commercial PA66 fibers (Najafi et al., 2017b;
Gupta, 2008).
It is interesting to see that a porous structure of PA6 prepared by dry-jet-wet
spinning technique appears after the removal of GaCl 3 (see Fig. 12.21).
The structure of as-spun polyamide fibers depends critically on the spinning speed
(take-off speed). The classical spinning systems of PA textile fibers have spinning

5 μm

Figure 12.21 Sliced section of PA 6 fibers prepared by conventional dry-jet-wet spinning after
GaCl 3 salt removal.