Multiple‐stage drawn ultrahigh molecular weight polyethylene/activated carbon fibers prepared with the assistance of supercritical CO₂

Abstract

Remarkable improved achievable draw ratios (DRs) and tensile strengths (σ 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 σ t s of single-and multiple-stage drawn scCO 2 UHMWPE/FAC fibers were considerably higher than those achievable DRs and σ t s found for the corresponding singleand 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 13.5 0.1 fiber. The σ 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 4.6, 1.6 and, 1.4 times of those σ 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 σ t s found for the proper single-or multiple-stage drawn scCO 2 UHMWPE/FAC fibers are proposed. K E Y W O R D S activated carbon, multiple-stage drawing, supercritical carbon dioxide, UHMWPE, ultimate tensile tenacity 1 | INTRODUCTION Much effort has been expended in the development of highperformance fibers with tensile strength ≥1.7 GPa. [1-14] Among these high-performance fibers, ultrahigh molecular weight polyethylene (UHMWPE) fibers have been the most fast-growing fibers due to their excellent tensile strength, lightweight, flexibility, chemical, and ultraviolet stability

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

“…For example, Xu et al 37 found that crystallite orientation increased to nearly perfect alignment with an orientation factor of 0.99 following a two‐stage hot drawing with an initial drawing temperature of 120°C and second‐stage drawing temperature of 130°C using industrial hot drawing equipment. Processing aids, such as supercritical carbon dioxide, can be employed to improve the drawing process as well 56 …”

“…Processing aids, such as supercritical carbon dioxide, can be employed to improve the drawing process as well. 56 Further optimization can be achieved by investigating the characteristics of UHMWPE-orange terpenes gelation and the spinning process parameters. It has been shown that the gelation and crystallization mechanisms vary significantly between the two leading solvents for UHMWPE gel spinning, decalin and paraffin, resulting in significantly different maximum draw ratios.…”

Influence of high-density polyethylene content on the rheology, crystal structure, and mechanical properties of melt spun ultra-high-molecular weight polyethylene/high-density polyethylene blend fibers

“…[5][6][7][8] Previous studies also indicate that the structure and mechanical properties of the fibers are greatly affected by the preparation process: the solvent quality somehow changes the entanglement density; 9 the restriction in fiber axis shrinkage is beneficial to the transformation of folded chain crystals into extended chain crystals; 10 and a high stretching temperature is conducive to the formation of shish-kebab crystals and microfibrillar crystals. 11,12 Research on gel UHMWPE fibers has been relatively comprehensive, and researchers are still trying to improve the gel spinning process, such as treating UHMWPE suspensions with supercritical CO 2 13,14 and using polyalphaolefin as a new solution. 15 However, gel spinning uses a dilute UHMWPE solution and requires an extraction process, which requires a large amount of organic solvent.…”

Processability and physico‐mechanical properties of ultrahigh‐molecular‐weight polyethylene using low‐molecular‐weight olefin wax

“…[ 21 ] Gelatinization using supercritical carbon dioxide (scCO 2 ) results in increased effective draw ratios and tensile strengths of single‐ and multiple hot stages drawn UHMWPE/functionalized activated carbon (FAC) fibers. [ 22 ] Oxidation in air medium of gamma sterilized UHMWPE implants on shelf life (immediately after irradiation; in the first 5 months; and between 5 and 30 months, respectively) reveals the prediction of superposition law for the augmented aging of UHMWPE based on sample thickness, irradiation dose, and aging time. [ 23 ] For enhanced aging studies of the steady gamma‐irradiated UHMWPE: temperature; heating rate; storage duration between the time gap before and after gamma irradiation; and the speeded aging are critical for controlling degradation rate during the aging phenomena.…”