DOI: 10.5593/sgem2017H/63/S26.071


R. Hron, F. Martaus, M. Kadlec, R. Ruzek
Thursday 23 November 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgemviennagreen.org, SGEM2017 Vienna GREEN Conference Proceedings, ISBN 978-619-7408-29-4 / ISSN 1314-2704, 27 - 29 November, 2017, Vol. 17, Issue 63, 563-570 pp; DOI: 10.5593/sgem2017H/63/S26.071


Geopolymers are innovative, ecological, low-cost, inorganic polymers derived from the naturally occurring geological materials which combine low temperature, polymer-like processing with high temperature stability and fire resistibility without toxic smoke generation. To increase efficiency of geopolymer composite materials in aerospace where the fire resistibility is critical, their incorporation into sandwich panels must be applied and evaluated.
This paper presents drum peel strength (ASTM D1781 standard) of both glass/phenolic prepreg based and carbon fibre/geopolymer based sandwiches. Several types of organic and inorganic adhesives were used to bond the laminate skin to foam and honeycomb cores. As the skin, three plies of carbon fabric Kordcarbon Industry (200 g/m2, 3K, plain) in 0°/90° warp/weft orientation were used. The cores had thickness of 10 mm. Specimens had dimensions of 76 x 465 mm.
In the group of foam core specimens, the best results were obtained for single operation sandwich bonding using uncured GPL 30 geopolymer resin that was manually impregnated with the carbon fabric and placed on the uncured foam core. Standard vacuum bag assembly was applied. The peel strength was two times higher than the reference glass/phenolic prepreg sandwich. In the group of honeycomb core specimens the best results showed Resbond® 989 bonded specimens. No special treatment was used, the peel ply was torn off from both pre-cured skins before the adhesive application. The peel strength was three times higher than the reference sandwich. Fracture surfaces were evaluated considering the peel strength and load-displacement curves.
This research can establish new fire resistible sandwich materials to be used in aerospace constructions.

Keywords: geopolymer, sandwich, peel strength.