# Thermal Performance of Medium and Long-Wave Infrared Emitters in PEEK-Based Thermoplastic Polymer Composites

## TL;DR

This study compares different infrared heating methods for PEEK-based composites, finding that long-wave emitters offer better energy efficiency and material integrity.

## Contribution

The study experimentally compares medium and long-wave infrared emitters for PEEK composites, revealing novel insights into their thermal performance and energy efficiency.

## Key findings

- Long-wave ceramic emitters achieve complete melting at 343 °C with high thermal uniformity and 18% lower energy demand.
- QTM emitters cause significant thermal gradients and surface degradation risks due to spectral mismatch.
- Consolidated laminates showed a tensile strength of 873 MPa and a tensile modulus of 56.3 GPa.

## Abstract

Carbon Fiber Reinforced Thermoplastic Polymer (CFRTP) composites, particularly those utilizing Polyetheretherketone (PEEK) matrices, are becoming more demanding in the automotive and aerospace industries because of their outstanding strength, resilience to impact, and capacity for recycling. The employed heating methodology to prepare these materials is important both to improve them through uniform temperature distribution and to manage the energy consumption. The current study aims to address the encountered issues by experimentally comparing the radiative–thermal performance of medium-wave (1.4–2.5 µm) Quartz Tungsten (QTM) and long-wave (3.5–5.5 µm) Ceramic (FFEH) infrared emitters using a modular laboratory-scale heating system. While QTM emitters provided rapid heating rates, they induce significant through-thickness thermal gradients and surface degradation risks due to spectral mismatch with the polymer. In contrast, long-wave Ceramic emitters demonstrate superior spectral compatibility with PEEK, expanding the safe processing window and achieving complete melting at 343 °C with high thermal uniformity and approximately 18% lower effective energy demand compared to QTM systems. Furthermore, the structural integrity of the consolidated laminates has been validated through tensile testing, yielding an average tensile strength of 873 MPa and a tensile modulus of 56.3 GPa. These findings confirm the importance of optimizing the emitter wavelength not only for energy efficiency, but also for ensuring matrix integrity and mechanical performance in high-performance composite manufacturing.