On the determination of the elastic modulus of ultraoriented high-strength film threads obtained by drawing of ultra-high-molecular-weight polyethylene xerogels

The influence of the gauge length $l_0$ of a sample on the modulus $E$ of ultraoriented film filaments of ultra-high-molecular-weight polyethylene (UHMWPE) has been elucidated. The filament samples are obtained by a multistage orientation drawing on a contact heater with achieving extremely high draw ratios as large as $\lambda$ = 120. Precursors were xerogels prepared by the drying of 1.5% UHMWPE gel solutions in decalin. A noticeable gain in “methodical” quantity $E$ from 100 to 230 GPa at $l_0$ increasing from 10 to 80 mm with a damping behavior has been established. The $E(l_0)$ dependence is shown to be described via the empirical equation that allows the $E$ value to be predicted as a function of $l_0$. According to the prediction, a saturation of the true value $E$ with a yield to a plateau at $E$ = 242 GPa occurs at $l_0$ = 200 mm.