Quinone-amine polyurethanes: new coupling agents for the steel-epoxy system

Abstract

ABSTRACT:A new series of quinone-amine polyurethanes (QAPs) were synthesized using toluene diisocyanate, polytetrahydrofuran, and an amine-quinone monomer (AQM1). The AQM1 was synthesized and characterized using spectroscopic techniques (UV, IR, NMR). The QAP synthesis involved a two-step process and yielded block copolymers. These polymers were characterized using infrared spectroscopy, thermal analysis methods (thermogravimetric analysis and differential scanning calorimetry) and gel permeation chromatography. Steel coupons were treated with dilute solutions of the QAPs and analyzed using surface spectroscopic techniques (X-ray photoelectron spectroscopy, infrared reflection spectroscopy). These tests indicate that the polymer shows chemical interactions with the steel surface. The QAPs were tested for their efficiency as polymeric coupling agents to enhance the adhesion of steel to epoxy. The coupling agent treated epoxy-steel torsional joints were tested in shear. They demonstrated 10 -15% dry strength improvement when compared to steel-epoxy controls. The QAPs can serve as very effective coupling agents for the steel-epoxy system.

Fracture and adhesion behaviors of epoxy resins modified with poly(amine‐quinone)

“…This result can be attributed to the addition of hydrophobic BB into the epoxy resins which increases the adhesion of the aluminum–epoxy systems through chemical interaction, mediated by the quinone molecule free electrons to the outer orbital of the metal surface through chemisorption 9–11, 20. A similar observation was made with quinone‐amine polyurethanes obtained from toluene diisocyanate, polytetrahydrofuran, and amine‐quinone monomer 21…”

Amine–quinone polyimides

“…These polyurethanes were shown to inhibit the corrosion of the commercial iron particles used in state‐of‐the‐art metal particle tape 10–13. We also demonstrated that amine–quinone polyurethanes promote the adhesion of epoxy to steel 14, 15…”

“…The amine–quinone polyurethanes and the amine–quinone polyimides provide an opportunity to test this model. We have already shown that amine–quinone polyurethanes promote adhesion of epoxy to steel 14, 15. We speculate that the amine–quinone polymers chemisorb to the iron surface and expect that the bond strength would depend on the nature of the amine–quinone functional group and the number of groups adsorbing to the iron surface.…”

“…We have already shown that amine-quinone polyurethanes promote adhesion of epoxy to steel. 14,15 We speculate that the aminequinone polymers chemisorb to the iron surface and expect that the bond strength would depend on the nature of the amine-quinone functional group and the number of groups adsorbing to the iron surface. The adhesive bond strength must be measured.…”

“…10 -13 We also demonstrated that amine-quinone polyurethanes promote the adhesion of epoxy to steel. 14,15 Recently we prepared an amine-quinone dianiline monomer (AQMDA) and used this monomer to prepare an amine-quinone polyimide (AQPI-2) by a two-stage condensation with 3,3Ј,4,4Ј-benzophenonetetracarboxylic dianhydride. 16 Our objective was to demonstrate whether we could combine the hightemperature properties inherent with polyimides with the corrosion protection of metal afforded by the amine-quinone functional group.…”