Phenylethynyl containing
imide-
silanes were prepared from aminoalkyl and aminoaryl alkoxy
silanes and 4-phenyletbynylphthalic anhydride in
toluene to form the
imide in one step or in N-methyl-2-pyrrolidinone (NMP) to form the
amide acid intermediate. Controlled molecular weight pendent phenylethynyl
amide acid oligomers terminated with aminoaryl alkoxy
silanes were prepared in NMP from aromatic dianhydrides, aromatic diamines, diamines containing pendent phenylethynyl groups and aminoaryl alkoxy silanes. The phenylethynyl containing
imide-silanes and controlled molecular weight pendent phenylethynyl
amide acid oligomers terminated with aminoaryl alkoxy silanes were used to improve the adhesion between phenylethynyl containing imide adhesives and inorganic substrates (i.e.
metal).
Hydrolysis of the alkoxy
silane moiety formed a
silanol functionality which reacted with the
metal surface to form a
metal-
oxygen-
silicon (oxane) bond under the appropriate
reaction conditions. Upon thermal cure, the phenylethynyl group of the
coupling agent reacts with the phenylethynyl functionality of phenylethynyl containing imide adhesives and becomes chemically bonded to the matrix. The
resultant adhesive bond is more durable (i.e. hot-wet
environmental resistance) than
adhesive bonds made without the use of the
coupling agent due to
covalent bond formation between the phenylethynyl containing imide-
silane coupling agent or the controlled molecular weight pendent phenylethynyl amide acid oligomers terminated with aminoaryl alkoxy silanes and both the
metal substrate and phenylethynyl containing imide adhesives.