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

Abstract

The tensile properties of ultra‐high molecular weight polyethylene (UHMWPE) fibers obtained from mixed solvents are addressed by virtue of improved solubility. In this work, olive oil (OO) was introduced as a poor solvent for the pre‐swelling of UHMWPE in decalin, and its mass percentage was intended to be 10, 20, 30, and 40 wt% of UHMWPE. Then UHMWPE fibers with high molecular weight retention and low entanglement were prepared with paraffin oil as spinning solvent by gel‐spinning and hot‐drawing. Unlike other samples, there is a more significant molecular chain disentanglement and higher molecular weight retention for UHMWPE fibers as OO addition is 20 wt%. Surprisingly, obtained UHMWPE fibers exhibit tensile strength up to 33.85 cN/dtex and tensile modulus of 1673.27 cN/dtex, with an increase of 24.0% and 32.3%, respectively, compared with that of UHMWPE fibers without decalin/OO pre‐swelling. Furthermore, the obtained UHMWPE fibers are accompanied by a marked improvement in melting temperature, crystallization and orientation.

Ultra‐high molecular weight polyethylene micro‐ribbon fibers gel spun using orange terpenes

“…It should be acknowledged that the WAXS‐measured crystallinity is significantly higher than that measured via DSC. However, the results of each method are consistent with other works reporting the DSC‐measured crystallinity of Dyneema SK60 40 and WAXS‐measured crystallinity of experimental UHMWPE fibers 17,29 . This underestimation via DSC has been reported before, 38,41 and there are many factors, such as sample mass and heating rate, that can affect DSC results 34,35,42 .…”

“…However, the results of each method are consistent with other works reporting the DSC-measured crystallinity of Dyneema SK60 40 and WAXS-measured crystallinity of experimental UHMWPE fibers. 17,29 This underestimation via DSC has been reported before, 38,41 T A B L E 2 Comparison of the melting enthalpy and calculated crystallinity of the sample fibers and Dyneema SK60 reference fibers after the first and second melting cycles.…”

“…16 Recently, olive oil was blended with decalin and used to pre-swell UHMWPE particles for enhanced polymer chain disentanglement preceding fiber spinning with paraffin oil, which resulted in 24% and 32% increases in tenacity and tensile modulus respectively. 17 Avoiding petrochemical solvents altogether can be accomplished by using orange terpenes, a food-grade biosolvent derived from orange peel waste, which was first demonstrated by Abdul Waqar Rajput in a 2013 dissertation and two subsequent publications. 11,18,19 UHMWPE powder was dissolved in orange terpenes and extruded from a 1 mm diameter die into a water coagulation bath.…”

“…Pre‐swelling of UHMWPE in a solvent, such as decalin, prior to spinning in paraffin oil has been shown to significantly improve the properties of the resulting fibers 16 . Recently, olive oil was blended with decalin and used to pre‐swell UHMWPE particles for enhanced polymer chain disentanglement preceding fiber spinning with paraffin oil, which resulted in 24% and 32% increases in tenacity and tensile modulus respectively 17 …”

Effects of stearic acid on the tensile properties of ultrahigh molecular weight polyethylene fibers

“…In order to enhance the tensile strength of UHMWPE fibers, it is crucial for improving the fluidity of UHMWPE during processing. The main methods of flow modification include low-viscosity polyolefin blending modification, 11,[14][15][16] lubricant blending modification, 17,18 solution system regulation, [19][20][21] and other modification methods. 7,22,23 Stearic acid (SA) is a popular fatty acid and a common lubricant, 24 applying in various polymer systems with the advantages of low cost and environmentally friendly.…”