Drawing-induced changes in the properties of polyethylene fibers prepared by gelation/crystallization

Scanning Force Microscopy on the Orientation of Gel‐Crystallized Ultrahigh Molecular Weight Polyethylene

“…TEM and SFM indicate a structural organization in which the packing of the PE chains within the nanofibrils is not uniformly crystalline. This is consistent with calorimetric experiments yielding 85-90% crystallinity [9,67] the remaining fraction, however, does not appear to be rubber elastic.…”

“…While bundling of microfibrils to fibrils ( Figure 12(a)) is well described [8,9,57,58], it is a controversial observation that microfibrils are constructed from apparently well defined smaller nanofibrils which represent the constituent thread of the microfibrils (Figure 12(b)). Observations at a higher magnification allow to visualize the molecular surface structure of the nanofibrils as it is shown in Figure 12(c).…”

High performance polyethylene nanocomposite fibers

“…As it commonly happens in semicrystalline polymers stretched above their glass transition temperature [35,36], the melting temperature (T m ) increases with the draw ratio. Above a draw ratio of 25, T m does not increase anymore and tends to level off at a value of about 142°C.…”

Deformation behavior of oriented UHMW-PE fibers

“…Taking further into account that the crystalline fraction is already nearly perfectly oriented [10,11], the observed increase in the sonic and the dynamic moduli upon loading (Figs. 8, 9) is related to further orientation of this "amorphous" fraction.…”

“…The Irvine/Smith model [9] predicts a unique modulus vs. draw ratio curve based on a simple two-phase model of, respectively, an oriented crystalline (helix, in their terminology) and amorphous fraction (coil). Another twophase model, in terms of crystalline and amorphous orientation functions was presented by Anandakumaran et al [10], who pointed out the pronounced influence of the amorphous orientation on the tensile modulus of oriented polyethylene. In an attempt to elucidate the nature of the "amorphous" component in oriented polyethylene, Deckmann et al studied oriented polyethylene fibers using NMR [11].…”