Fibers comprising a propylene homopolymer or a copolymer of propylene and
at least one of ethylene and one or more unsaturated comonomers exhibit desirable
properties. The homopolymers are characterized as having 13C NMR peaks
corresponding to a regio-error at about 14.6 and about 15.7 ppm, the peaks of about
equal intensity. The copolymers are characterized as (A) comprising at least about
60 weight percent (wt %) of units derived from propylene, and (B) having at least
one of the following properties: (i) 13C NMR peaks corresponding to
a regio-error at about 14.6 and about 15.7 ppm, the peaks of about equal intensity,
(ii) a B-value greater than about 1.4 when the comonomer content of the copolymer
is at least about 3 wt %, (iii) a skewness index, Six, greater than
about -1.20, (iv) a DSC curve with a Tme that remains essentially the
same and a Tmax that decreases as the amount of comonomer in the copolymer
is increased, and (v) an X-ray diffraction pattern that reports more gamma-form
crystals than a comparable copolymer prepared with a Ziegler-Natta (Z-N) catalyst.
