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

Abstract

The molecular weight loss of ultra‐high molecular weight polyethylene (UHMWPE) fibers is extremely serious in comparison with raw materials due to the high temperature and strong shearing during dissolving process. In this study, decalin was introduced as preswelling solvent and the dissolving system was regulated to improve the solubility of UHMWPE in paraffin oil without severe degradation so as to prepare UHMWPE fibers with high molecular weight retention and low entanglement. UHMWPE was preswelling in decalin with different content, the mass ratio of decalin to UHMWPE were 1:1, 1.5:1, 2:1, 2.5:1, and 3:1. All UHMWPE fibers were prepared by gel‐spinning and hot‐drawing. UHMWPE fibers possess the highest molecular weight after preswelling of UHMWPE in decalin (with a mass ratio of 3:1 to UHMWPE, namely UPE/dec‐s‐3 sample). What's more, the entanglement of UHMWPE fibers gained from UPE/dec‐s‐3 sample has been observably diluted in comparation to that from UPE‐neat and other swollen samples. More importantly, the tensile strength and modulus of UHMWPE fibers obtained from UPE/dec‐s‐3 sample can reach 31.41 and 1446.26 cN/dtex, increased by 15.1% and 14.3% compared with UPE‐neat fibers, respectively. Besides, the thermal and crystallization behavior of UHMWPE fibers prepared from swollen UHMWPE have also been boosted.

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

“…In our previous work, 26 it was found that the obtained fibers possessed the best high-strength and high-modulus properties when UHMWPE was swollen in 300 wt% decalin at 100 C for 10 min. A certain amount of OO (10, 20, 30, and 40 wt% of UHMWPE powder) was added to participate in the swelling of UHMWPE in decalin at 108 C under mechanical stirring on the basis of above swelling process.…”

“…The swelling ratio of UHMWPE is a significant parameter to characterize its swelling behavior. In our previous study, 26 it was observed that the swelling ratio of UHMWPE could achieve 1.53 when it was swollen for 10 min in 300 wt% decalin at 100 C. The determination of swelling temperature and swelling time is indispensable to reflect the swelling behavior of UHMWPE. In order to demonstrate more excellent swelling property, increasing swelling temperature is a feasible and effective method.…”

“…Furthermore, we also provided a strategy for UHMWPE processing using decalin as swelling solvent and paraffin oil as spinning solvent, high tensile properties of resultant fibers are achieved with this protocol. 26 What's more, some studies [27][28][29][30][31] reported the swelling of polymer in mixed solvents, which comprised two-components: a good solvent and a poor solvent for polymer. Yamaguchi et al 27 used the binary solvent of o-dichlorobenzene (ODB) as good solvent and hydrocarbon as poor solvent to eliminate the residue of suppressed aggregate extraction development (SAGEX) resist, indicating hydrocarbon as poor solvent can lead to little swelling of polymer and reduce the dissolving of SAGEX resist in ODB.…”

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

“…[12][13][14][15] 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 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.…”

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.…”