Preparation of Polyethylene Fibers with Enhanced Thermal Stability and Hydrophilicity by UV Irradiation

Abstract

Conventional polyethylene(PE) fibers face limitations in large-scale industrial applications due to their poor thermal stability and inherent hydrophobicity, which restrict processing temperatures and dyeability, especially in blended fabric production. In this research, a one-step ultraviolet(UV) irradiation technology was employed to modify medium molecular weight PE fibers through simultaneous crosslinking and grafting modifications, aiming to enhance their thermal stability and hydrophilicity. The modification employed a cost-effective, UV-initiated crosslinking system consisting of benzophenone(BP) as the photoinitiator and triallyl isocyanurate(TAIC) as the co- crosslinker. Acrylic acid(AA) was selected as the grafting monomer. These modifiers were thoroughly mixed with the PE matrix in a liquid-phase environment, and the mixture was melt-spun into fibers. The resulting fibers were then subjected to UV irradiation, which triggered the crosslinking and grafting reactions. The effects of the mass fraction of each component and irradiation parameters on modification efficacy were systematically investigated, followed by a comprehensive characterization of the modified PE fibers. The modified PE fibers achieved optimal thermal stability under the following conditions:2. 0% mass fractions for both BP and TAIC, a UV irradiation intensity of 2 000 mW/ cm ², and an equivalent irradiation time of 60 s. This synergistic modification approach enables the fibers to maintain superior morphological integrity and mechanical performance when exposed to elevated temperatures ranging from 130 to 150^°C. Meanwhile, an AA grafting mass fraction of 2. 0% maximizes hydrophilicity with minimal impact on other properties, as evidenced by a dramatic reduction in the water contact angle(WCA) from 105. 0^° (hydrophobic) to 48. 4^°(hydrophilic). These improvements confirm the effectiveness of the modification strategy in synergistically enhancing both thermal stability and hydrophilicity of PE fibers.

Keywords

polyethylene(PE) fiber / ultraviolet(UV) irradiation / crosslinking modification / graft modification / thermal stability / hydrophilicity

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