An acrylic adhesive composition includes a first part including an aminoborane initiator and acrylate or/and methacrylate monomers, and a second part including inert microcapsules of a cure activator and acrylate monomers, wherein the microcapsules are breakable, such that when broken, the first part reacts with the second part and the acrylic adhesive begins to cure. A two-part structural adhesive includes a suspension component containing an aminoborane initiator, and microcapsules containing an encapsulated component, wherein the microcapsules are dispersed in the suspension component. A method of activating an aminoborane initiator suspension to form a structural adhesive includes adding microcapsules containing an encapsulated component, to the aminoborane initiator suspension at a predetermined ratio, and breaking the microcapsules to activate curing.