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

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.