Microextrusion Foaming of Polyetheretherketone Fiber: Mechanical and Thermal Insulation Properties

Abstract

Porous polyetheretherketone (PEEK) materials, especially those with controllability and excellent mechanical properties, have always been the development hotspots in the fields of thermal insulation and medical bone implants. However, the traditional sulfonation process of porous PEEK materials has the problems of applying abundant high‐concentration solvents, high production costs, low resource utilization, and environmental pollution. Herein, a microextrusion foaming process with using CO2 as a blowing agent is proposed for creating porous PEEK fibers under different parameters. The as‐prepared porous PEEK fiber possesses well‐defined cell morphology, high toughness (136.2%), and excellent thermal insulation properties (13.4 ± 1.50 °C), resulting from the high cell nucleation rate and limited‐time cell growth (<0.85 s). All in all, the microextrusion foaming process provides unprecedented opportunities for continuous manufacturing and functional development of porous PEEK fibers.

A Review of the Preparation of Porous Fibers and Porous Parts by a Novel Micro-Extrusion Foaming Technique

“…The combination of high-pressure mixing and a sudden pressure drop can readily lead to the coalescence, rupture, and annihilation of internal cells within the foam melt. This phenomenon results in an uneven cell size and distribution, a sparse cell structure, and other varied structural morphologies in the final product [ 75 , 90 , 91 , 92 , 93 , 94 , 95 ]. To improve the cell morphology in continuous extrusion foaming, it is necessary to control complex parameters to enhance cell nucleation with nanoparticles and to restrict cell coalescence by increasing the melt strength of the polymer [ 93 , 96 , 97 ].…”

“…Based on our preceding discussion, the fabrication of porous fibers using the MEF method is not only theoretically feasible but also holds great promise for practical applications. Li et al [ 90 ] first used the MEF method to prepare porous polyetheretherketone (PEEK) fibers and achieved success. They utilized PEEK’s low gas diffusion rate and high T g to manufacture porous PEEK fibers with internal micropores and rough surface structures, and they studied the effects of different process parameters on the pore morphology of porous PEEK fibers.…”

“…Multifunctional porous fibers with excellent mechanical properties have received widespread attention in the fields of personal thermal management textiles and intelligent wearable devices [ 25 ]. The porous fibers prepared by MEF not only have high production efficiency (up to 10.5 cm/s) but also have diverse cell structures and excellent weaving properties [ 90 ]. The group of Zhai [ 75 , 91 ] explored a series of properties of physically foamed PEEK and PEI porous fibers, demonstrating their potential for application in the textile field.…”

Solid-state foaming of poly(ether-ether-ketone)/hydroxyapatite composites

“…It was found that foaming of high crystallinity PEEK yielded small cells of about 5–10 um, which are generally considered too small for bone tissue engineering. Li et al 20 used the microcellular extrusion foaming method with CO2 to fabricate porous PEEK filaments. High toughness and excellent thermal insulation properties were achieved; however, the filaments were foamed during the extrusion process, with limited control on the pore size.…”