Polymerizable compositions made with polymerization initiator systems based on organoborane amine complexes

A bonded composite comprising a first substrate, a second substrate, and a polymerized acrylic composition that adhesively bonds the first and second substrates together wherein the acrylic composition is the polymerization product of a polymerizable acrylic system that comprised:

• (a) at least one acrylic monomer;
• (b) an effective mount of an organoborane amine complex having the structure:
• ##STR15## wherein:
• R.sup.1 is an alkyl group having 1 to 10 carbon atoms;
• R.sup.2 and R.sup.3 are independently selected from the group consisting of alkyl groups having 1 to 10 carbon atoms and phenyl-containing groups;
• R.sup.4 is selected from the group consisting of CH.sub.2 CH.sub.2 OH and (CH.sub.2).sub.3 NH.sub.2 wherein x is an integer greater than 2;
• R.sup.5 is hydrogen or an alkyl group having 1 to 10 carbon atoms;
• and
• the nitrogen atom to boron atom ratio is about 1:1 to 1.5:1;
• and
• (c) an effective mount of an acid for initiating polymerization of the acrylic monomer.