Volume 10,
Issue 5, 2001
RESOLE
RESIN AS SIZING AGENT FOR ARAMID FIBRES
J.
Bousoulas, P. A. Tarantili, A. G. Andreopoulos
National
Technical University of Athens
Dept.
of Chemical Engineering - Lab. of Polymer Technology
Iroon
Polytechniou 9, Zografou Campus 157 80, ATHENS – GREECE
(Received 8/01;
accepted 10/01 )
ABSTRACT
A comparative study was made
in order to evaluate the interfacial characteristics of treated aramid
fibres and epoxy resins. Surface treatment by coating with phenolic
resins was performed using the following two systems: a) alkaline
aqueous solution of resole resin and b) solution of novolac resin
containing hexamethylene-tetramine as cross-linking agent. After these
treatments, the modified aramid fibres were used for the preparation of
reinforced epoxy specimens. The flexural properties of these specimens
were determined and the results were discussed taking into consideration
the surface characteristics of the modified fibres, as derived from
pull-out tests and contact angle measurements. It was shown that both
coatings are adequate to promote interfacial adhesive bonding to epoxy
matrices due to the chemical reactivity of phenolic resins to the epoxy
matrix as well as to their affinity with the aramid fibre surface.
Resole appeared more efficient than novolac as it produces uniform
continuous films, shows increased reactivity due to its higher hydroxyl
content and can be easily processed because it is soluble in alkaline
water solutions.
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