Co-cure joining of epoxy composites with rapidly UV-irradiated PEEK and PPS composites to achieve high structural integrity

Dong Quan,René Alderliesten,Clemens Dransfeld,Ioannis Tsakoniatis,Rinze Benedictus

doi:10.1016/j.compstruct.2020.112595

Dong Quan, René Alderliesten + Show 3 more

Open Access

https://doi.org/10.1016/j.compstruct.2020.112595

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Journal: Composite Structures	Publication Date: Jun 13, 2020
Citations: 23	License type: cc-by

Affiliation: Delft University of Technology

Abstract

Efficient joining of hybrid thermoset/thermoplastic composite joints is critical to produce high performance lightweight structures while keeping the cost low. Herein, a high-power UV-irradiation technique was proposed to rapidly active the surfaces of PEEK and PPS composites for the following co-cure joining with epoxy composites. A single lap-shear joint test and a double cantilever beam test were used to evaluate the mechanical and fracture performance of the hybrid joints. The experimental results revealed that high structural integrity of the hybrid joints was achieved upon applying a 6 s UV-treatment to the thermoplastic composites. For example, the lap-shear strength and fracture energy of the adhesive bonded hybrid joints were above 25 MPa and 800 J/m2, respectively. Overall, high-power UV-irradiation proved a highly efficient, rapid and low-cost method to treat thermoplastic composites for the co-cure joining with epoxy composites, and hence it demonstrated significant promise in industrial mass production.

Highlights

Fibre reinforced polymers (FRPs) are becoming increasingly attractive to multiple industries, including automotive and aerospace sectors, due to their lightweight and excellent structural performance
It was observed that applying the Ultraviolet light (UV)‐ treatment to the thermoplastic composites (TPCs) notably increased the O/C ratios of the TPC surfaces in both cases
It was reported that applying atmospheric‐pressure plasma (APP) [35,36,37,38] and low‐pressure plasma (LPP) [39,40,41,42] treatments to the PEEK and PPS surfaces resulted in substrate damage and/or cohesive failure of the adhesive joints during the lap‐shear test

Summary

Introduction

Fibre reinforced polymers (FRPs) are becoming increasingly attractive to multiple industries, including automotive and aerospace sectors, due to their lightweight and excellent structural performance. While thermosetting‐based composites (TSCs) are more traditional and lower cost, thermoplastic composites (TPCs) possess a number of advantages over TSCs, including high fracture toughness, cost‐ effective manufacturing process and recyclability. Effective joining of TPCs with TSCs and other dissimilar materials becomes critical to manufacture such components with combined materials. Three major technologies exist for the joining of thermoplastics and FRPs, including mechanical fastening [2,3], welding (fusion bonding) [4,5] and adhesive bonding [6,7]. Adhesive bonding offers many advantages for FRP joining, including the possibility of making light‐ weight constructions, the ability to join any pair of dissimilar materials with a relatively uniform stress‐distribution, and the possibility to seal the entire bonding area and to provide high joint strength and durability. Adhesive joining is unique for joining thin‐ walled sections with large surface area and elements with a significant difference in thickness [11]

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