Berlin 2012 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 2: Nanoparticles and Composite Materials
CPP 2.7: Talk
Monday, March 26, 2012, 11:00–11:15, C 243
Reactive epoxies with functional zeolite fillers: IR spectroscopy and PALS studies — •Klaus Rätzke1, Qasim Shaikh1, Jan Gaukler2, Wulff Possart2, and Franz Faupel1 — 1Materials Science Univ. Kiel, Germany — 2Adhesion and Interphases, Materials Science, Saarbrücken, Germany
Epoxy-dicyandiamide (Dicy) formulations frequently contain a free accelerator for reducing the curing temperature and the time for network formation. However, an accelerator reduces the shelf life of these adhesives. This study compared the reaction kinetics during the storage at 60 °C for a pre-cured epoxy adhesive (EP = diglycidyl ether of bisphenol A and Dicy, mass ratio 100 : 6.7, pre-cured at 150 °C for 1 h) mixed either with free accelerator or with the same concentration of accelerator immobilised in micro or nano-zeolite fillers [1]. During storage, the IR study probed the chemical modifications. They lead to increasing crosslinking density and a loss of free volume as detected by positron annihilation lifetime spectroscopy (PALS) [2]. Crosslinking proceeds to the chemical vitrification. Additionally, the glass transition and the free volume parameters were investigated for the three systems as a function of temperature by PALS after thermal curing.
[1] K. Rätzke, M. Q. Shaikh, F. Faupel, P. L. M. Noeske International Journal of Adhesion & Adhesives, 30 (2010) 105
[2] M. Q. Shaikh, K. Rätzke, J. Ch. Gaukler, W. Possart, F. Faupel, J. Mater. Res., 26, (2011) 2877