ORS7-0372
Sulfur-Driven Reactive Processing of Carbon Fiber Reinforced Polyether Ether Ketone Composites
Topic
S7. Innovations in Polymeric Composites: From Design and Processing to Industrial Applications
When and Where
Sep 30, 2026
11:35 - 11:50
Room 107
Session Chairs
Seokhoon AHN
Presenter(s)
Amir Asadi (Texas A&M University)
Co-Author(s)
Abstract
We present a simple reactive-processing strategy based on elemental sulfur to engineer crystallization and simultaneously improve strength and fracture toughness in carbon fiber-reinforced polyether ether ketone (CF/PEEK) composites, overcoming the conventional trade-off between these properties. We investigate the effects of sulfur on crystalline architecture, mechanical performance, and interlaminar fracture behavior in CF/PEEK laminates. In addition, we use graphene nanoplatelets (GNPs) to showcase the advantage of elemental sulfur over using conventional nanomaterials for enhancing properties.
Sulfur and CNC-stabilized GNPs were introduced through a scalable spray-coating process onto the prepregs, followed by vacuum-assisted compression molding. Sulfur initiated controlled chain scission and crosslinking reactions within PEEK, reducing melt viscosity by nearly an order of magnitude and improving processability. At low sulfur concentrations, enhanced chain mobility promoted crystallization, increasing the degree of crystallinity from ~45% to >54% in CF/PEEK laminates. When combined with CNC:GNP hybrid fillers, crystallinity slightly increased due to the synergistic effects of sulfur-enabled chain mobility and GNP-induced heterogeneous nucleation. Structural analysis revealed significant changes in lamellar organization and crystal stacking, demonstrating sulfur-driven modification of the crystalline architecture.
These microstructural changes translated into improved composite performance. Trace sulfur additions increased flexural strength from ~780 MPa to nearly 900 MPa while maintaining interlaminar shear properties. Further, the addition of sulfur improved the mode I and Mode fracture toughness by 80%.This work establishes a scalable framework linking sulfur-driven crystallization control to improved mechanical and fracture performance in high-temperature thermoplastic composites.
Sulfur and CNC-stabilized GNPs were introduced through a scalable spray-coating process onto the prepregs, followed by vacuum-assisted compression molding. Sulfur initiated controlled chain scission and crosslinking reactions within PEEK, reducing melt viscosity by nearly an order of magnitude and improving processability. At low sulfur concentrations, enhanced chain mobility promoted crystallization, increasing the degree of crystallinity from ~45% to >54% in CF/PEEK laminates. When combined with CNC:GNP hybrid fillers, crystallinity slightly increased due to the synergistic effects of sulfur-enabled chain mobility and GNP-induced heterogeneous nucleation. Structural analysis revealed significant changes in lamellar organization and crystal stacking, demonstrating sulfur-driven modification of the crystalline architecture.
These microstructural changes translated into improved composite performance. Trace sulfur additions increased flexural strength from ~780 MPa to nearly 900 MPa while maintaining interlaminar shear properties. Further, the addition of sulfur improved the mode I and Mode fracture toughness by 80%.This work establishes a scalable framework linking sulfur-driven crystallization control to improved mechanical and fracture performance in high-temperature thermoplastic composites.
