Multiple-stagedrawn ultrahigh molecular weight polyethylene/activated carbon fibers prepared with the assistance of supercriticalCO2

Remarkable improved achievable draw ratios (DRs) and tensile strengths (sigma(t)s) of multiple-stage drawn ultrahigh molecular weight polyethylene (UHMWPE)/functionalized activated carbon (FAC) fibers prepared with the aid of supercritical carbon dioxide (scCO(2)) were first reported. The achievable DRs and sigma(t)s of single- and multiple-stage drawn scCO(2)UHMWPE/FAC fibers were considerably higher than those achievable DRs and sigma(t)s found for the corresponding single- and multiple-stage drawn UHMWPE/FAC fibers spun from gel solutions gelatinized in nitrogen atmosphere. It is worth noting that the largest achievable DR obtained for the most proper five-stage drawn scCO(2)UHMWPE/FAC fiber approached 688, which is approximately 40% larger than the achievable DR found for the single-stage drawn scCO(2)F(100)FAC(0.1)(13.5)fiber. The sigma(t)found for the most proper five-stage drawn scCO(2)UHMWPE/FAC fiber reached an extraordinarily high value of 13.4 GPa, which is similar to 4.6, similar to 1.6 and, similar to 1.4 times of those sigma(t)s found for the optimal single-stage drawn UHMWPE, UHMWPE/FAC and scCO(2)UHMWPE/FAC fibers, respectively. Considerably smaller lamellar thicknesses and dynamic transition temperatures were detected for scCO(2)UHMWPE and scCO(2)UHMWPE/FAC as-prepared fibers compared with the equivalent UHMWPE and UHMWPE/FAC as-prepared fibers, respectively. Specific surface area, morphological, and Fourier transform infrared analyses of the FAC particles and orientation factor analyses of the single- and multiple-stage drawn UHMWPE, UHMWPE/FAC, scCO(2)UHMWPE, and scCO(2)UHMWPE/FAC fibers were performed. Possible reasons accounting for the remarkable improved achievable DRs and sigma(t)s found for the proper single- or multiple-stage drawn scCO(2)UHMWPE/FAC fibers are proposed.