A copolymer according to the inventions may be transparent, has a high fracture strain and a high elasticity.

Most preferably, the peak engineering stress is about 4.4 g/d, and the break strain is about 24 percent.

The inventive fiber has a peak engineering stress greater than about 1.6 g/d and a break strain greater than about 15.5 percent.

As soon as the failure strain is reached at one of the localized positions, the entire structure fails.

The strain value at failure for the filamentary material of the second ply (70) is greater than the 0 and 90 degree filamentary material of the first layer (64).

A preferred range for the peak engineering stress is from about 3.0 g/d to about 5.0 g/d, and a preferred range for the break strain is from about 20 percent to about 50 percent.

The beam's ductility is characterized either by the strain to failure or the percentage change in length.

The strip has a fracture strain of 0.01 or more, a lamination factor of 0.8 or more, and a core loss of less than 0.2 W/kg at 60 Hz and 1.4T.