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.

A novel series of quinone-amine polyurethanes (QAPs) were synthesized and tested for their efficiency as corrosion-inhibiting polymeric coupling agents to enhance the adhesion of epoxy to steel. These polymers were characterized using infrared spectroscopy, thermal analysis methods (TGA and DSC), tensile testing, and gel permeation chromatography. The coupling agent-treated epoxy-steel torsional joints were tested (dry and after wet environments) in shear. These joints demonstrated a 10-15% dry strength improvement when compared with epoxy-steel control joints. The coupling agent-treated epoxy-steel joints also exhibited excellent hot water (60°C) durability while the epoxy-steel control joints fell apart in 3 days. Epoxy-steel lap shear joints were made with the QAP coupling agents and fractured in shear to study the locus of failure. These joints fail either close to the coupling agent-epoxy resin interface or inside the epoxy resin. Steel coupons were treated with the QAP coupling agent and top-coated with epoxy resin for testing in a lab-scale saltspray chamber. These coupons demonstrated excellent corrosion resistance when tested for over 15 days. The QAPs can serve as very effective corrosion-inhibiting coupling agents for the epoxy-steel system.

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