From Fig. 4, it can be seen that the fibers display two strong
endothermic peaks in the first run while the isotropic UHMWPE
display only one peak at a much lower value. The pattern of the
fibers suggests the existence of a combination of constrained and
non-constrained phases of PE in the fibers [4]. The first peak
around 153 C is assigned to the melting of orthorhombic