The vibrating annealing method (VA) was applied to polyarylate fiber t
o improve its mechanical properties. The VA treatment was repeated twi
ce under a frequency of 100 Hz and an amplitude of 5 mm for 10 minutes
. The first and second VA treatments (VA1 and VA2) were carried out at
200-degrees-C under tensions of 76 MPa and 84 MPa, respectively. The
polyarylate fiber used in this study was Vectran supplied by Kuraray C
o., Ltd. The changes in mechanical properties and in thermal shrinkage
with the processing were investigated. The dynamic modulus (E') incre
ased stepwise with the processing. The E' value of the original fiber
was 49 GPa at 25-degrees-C, and that of the VA2 fiber was 83 GPa at 25
-degrees-C. Although the original fiber shrank rapidly in the range of
50-degrees-C to 100-degrees-C, the VA fibers shrank gradually. The VA
2 fiber has an excellent dimensional stability: a shrinkage of 0.42% a
t 190-degrees-C.