JEC COMPOSITES MAGAZINE - Issue #51 - September 2009 - 58

KNOW-HOW Bonding …/… Nano-toughening structural epoxy adhesives adhesives whilst the third one is the new “ABiTAS adhesive” that has been developed within the programme. Both Epibond® 1590 A/B and ABiTAS adhesive are based on nanoparticle technology, the ABiTAS version representing a further step in performance. More information ABiTAS is an EU-funded research programme that addresses the need for fundamental advancements in structural adhesive bonding for aerospace applications. Within the programme, Huntsman is responsible for the research and development of new adhesive chemistry. Combined with activities for automated surface pre-treatment of adherents, on-line monitoring of treated surfaces and advanced application & assembly technology, this programme will lead to more robust, flexible and economic processing, bringing about new structural concepts based on adhesive bonding and Ti-CFRP-composites. Main features Nanoparticle-toughened ABiTAS adhesive Fig. 6: Lap shear values. • Strength retention at high temperature • High roller peel strength (7.9 N/mm) • High interlaminar fracture toughness energy GIC (1,840 J/m2) • Retention of Tg after hot/wet conditioning • Long open time: up to 3 hours • Non-slump up to 2-3 mm • Suitable rheology for dosing/mixing equipment Conclusion The use of a dispersed organic nanoparticle phase dramatically improves the toughening and fatigue resistance of epoxy thermoset materials, with very little negative impact on their modulus or temperature resistance. This makes this technology highly Fig. 8: SEM image of fracture surface. suited for structural adhesive bonding in applications where dynamic stress is encountered, such as wind blades, sports and transport applications. The combined properties of the nanoparticle-toughened adhesive developed within the ABiTAS programme make it an excellent candidate as a replacement for aerospace film adhesives. It offers enormous potential savings in terms of manufacturing times and costs as compared with the autoclave methods currently used in the aerospace industry. More information: www.hunstman.com Contacts: duncan_howland@huntsman.com olivier_de_verclos@huntsman.com Acknowledgments The authors gratefully acknowledge the financial support of the EU (FP6 STREP Project ABiTAS). Fig. 7: Peel strength values. Araldite® 420 A/B displays a very high peel and shear strength at 23°C, making it a very good tough adhesive for service temperatures up to 40°C. However, due to its poor strength retention at 80°C, it is not suitable for high-temperature applications. Toughness is driven by a low-crosslink-density flexible network. The nanoparticle technology makes it possible to reach a high level of toughness without sacrificing high-temperature strength, as can be seen with Epibond® 1590 A/B and the ABiTAS adhesive. Epibond® 1590 A/B is the first-generation nanotoughened adhesive with high temperature strength and medium peel. The combination of performance is driven by a highly crosslinked epoxy-amine rigid network with copolymers that phase-separate upon cure. The second-generation nanotoughened ABiTAS adhesive is based on a similar concept, but the level of toughness achieved is further improved. The domain size of the dispersed phase is dictated by the type of copolymer, the epoxy-amine system and the cure conditions. Figure 8 shows a SEM image of the fractured ABiTAS adhesive, where a bimodal distribution of the dispersed phase is clearly visible. The nanospherical phase has diameters in the range of 100 to 400 nm. Legal information Araldite® and Epibond® are registered trademarks of Huntsman Corporation or an affiliate thereof in one or more, but not all, countries. 58 jec composites magazine / No51 September 2009

http://www.hunstman.com

JEC COMPOSITES MAGAZINE - Issue #51 - September 2009

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #51 - September 2009