The Abnormal Behaviour of Epoxy Resin in Acidic and Basic Organic Media

The present work deals with the influence of aging effect on epoxy resin exposed to different organic acidic and basic media. Four organic acids, acetic acid (AA), formic acid (FA), n-butyric acid (BAc) and trifluoroacetic acid (TFA), beside the following, four Amines, aniline (AN), ethanol amine (EA), n-butyl amine (BAm) and n-methyl benzyl amine (MBA) were used.
The minimum values of W% in acidic medium was detected at low temperature (10C) then increased at 30C and attained relatively constant values at 50C. Trifluoroacetic acid shows a maximum values of W% while minimum values observed in FA according to the following sequence.
TFA > BA > AA > FA
In basic media (amines), W% values not exceed 1% in BA, while they reach almostly 30% in AN and MBA. W% values are decreased in the following order:
MBA > AN > EA > BAm
Except in EA and BAm, it was found that the values of W% is directly proportional to the formula weight. Amines with aromatic rings like AN and MBA which considered as weak bases are behave in similar manner as acids and give high W% values. This study decleare that the organic compound added to the epoxy inspite of their nature (acid or base), were effect on the epoxy weight through certaine sterical or chemical interaction. The treatment of epoxy resin with amines rised there softening temperature, where organic acids have no effect .