Effect of polyalphaolefin oils as a solvent in gel‐spinning of ultra‐high molecular weight polyethylene fibers

Abstract

In this work, lubricants based on polyalphaolefin with different viscosities were evaluated in the processing of UHMWPE fibers. All fibers were obtained by extrusion with 0.04 to 60 wt% of polyalphaolefin oils with different kinematic viscosities and densities (in ascending order: PAO8, PAO40, and PAO100), under screw speed of 20 to 60 rpm with a nozzle of 1.82 mm diameter. Also, n-hexane was used to extracting the oils from UHMWPE fibers. The fibers did not undergo the drawing process. It was observed that the fibers that underwent process with PAO40 showed the highest linear density, achieving 3273 tex, indicating the orientation of the crystals in a compact morphology inside the extruder and the higher relaxation after leaving the nozzle, increasing die-swell. Microscopic analysis revealed roughness in fiber as the insertion of PAO100 oil increased, while fibers with PAO40 proved to be more densified.In addition, the fibers processed with PAO40 have an increase in thermal stability after n-hexane extraction, with degradation temperature T max of 482 C in comparison with 476 C for the neat UHMWPE.

Enhanced tensile properties of ultra‐high molecular weight polyethylene fibers by solubility improvement with mixed solvents

“…19,20 Some research efforts also paid great attention to new spinning solvents for UHMWPE. Da Silva Chagas et al 21,22 prepared UHMWPE fibers with polyalphaolefin oil as solvent by gel-spinning, the resultant fibers showed fewer entanglement, higher crystallinity and denser crystal orientation, but the tensile properties were not reported. Fang et al 23 also used polybutene as spinning solvent to prepare UHMWPE fibers, although high-strength fibers cannot be obtained, the extraction efficiency expresses better than that of gel-spun fibers with paraffin oil.…”

Regulating the dissolving system of ultra‐high molecular weight polyethylene to enhance the high‐strength and high‐modulus properties of resultant fibers

“…The key processes of UHMWPE fibers production by gel‐spinning‐hot‐drawing include UHMWPE solution preparation, gel‐spinning forming, solvent removal of gel fibers and ultra‐hot drawing of dry gel fibers 17,18 . The first priority of gel‐spinning method is to prepare a homogeneous UHMWPE spinning solution.…”

“…4,16 The key processes of UHMWPE fibers production by gel-spinning-hot-drawing include UHMWPE solution preparation, gel-spinning forming, solvent removal of gel fibers and ultra-hot drawing of dry gel fibers. 17,18 The first priority of gel-spinning method is to prepare a homogeneous UHMWPE spinning solution. Since UHMWPE has an ultra-long flexible chain structure, there are serious entanglements between molecular chains and within molecular chains.…”