Purpose: To evaluate the effects of carboxylic and phosphate functional monomers on the bond strength and durability of an acrylic resin joined to a magnetizable stainless steel and its component metals. Materials and Methods: Disk specimens (10 and 8 mm in diameter and 2.5 mm thick) were prepared from SUS XM27 stainless steel, high-purity iron, and chromium metals. The specimens were ground with abrasive paper, and divided into an unprimed control group and 4 groups primed with: 1. Alloy Primer (thione and phosphate); 2. Estenia Opaque Primer (phosphate); 3. Mr. Bond (aliphatic carboxylic acid); or 4. Super-Bond C&B Liquid (aromatic carboxylic anhydride). The disks were bonded with tri-n-butylborane (TBB)-initiated resin, and the shear bond strengths were determined both before and after thermocycling (20,000 X, 5°C - 55°C). The debonded surfaces were analyzed using Xray diffraction (XRD). Results: The Alloy Primer and Estenia Opaque Primer materials containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) effectively bonded the steel (30.3 to 32.4 MPa) and iron (33.6 to 34.8 MPa), whereas the four acidic primers bonded chromium (24.6 to 32.3 MPa). X-ray diffractometry detected corroded iron at the debonded interface. Conclusion: Bearing in mind the limitations of the present study, the use of two primers with MDP is recommendable for bonding SUS XM27 steel with TBB-initiated resin. Iron was considered to be a corrosive factor at the adhesive interface, although the associated bonding characteristics were adequate.
Keywords: butylborane, carboxylic acid, chromium, iron, phosphate, stainless steel