JOURNAL OF APPLIED POLYMER SCIENCE, cilt.106, sa.1, ss.46-52, 2007 (SCI-Expanded, Scopus)
To improve the brittleness of high ortho
novolac resins, at first, high ortho novolac resins (N) were
synthesized and condensation reactions between N and
flexible diacids such as adipic acid (DA4) and azelaic acid
(DA7) were carried out with different amounts of diacids,
in the presence of zinc acetate as catalyst, in toluene as solvent.
To characterize the diacid-modified resins (MN), FTIR
analysis, TGA and DSC techniques were used. The morphologies
of MN were also investigated. Moldings were
prepared from the mixture of MN, fillers, and curing agent
hexamethylenetetramine. Mechanical properties of these
moldings were also determined. The results showed that
high ortho novolac resin was toughened by the incorporation
of flexible diacids in the polymer backbone and these
modified resins can be used as a matrix resin of composite
materials.