| Abstract: | A series of poly(n-butyl acrylate)/polystyrene IPNs and semi-1 IPNs with deliberately controlled graft levels were synthesized via a urethane chemical coupling method. Also prepared were a series of semi-2 IPNs with the molecular weight of polymer II as the variable. The more highly grafted IPNs displayed poorly defined morphologies in which the domain structures were irregular and phase domain boundaries were characterized by fibrillar and interphase regions. A single glass transition peak was another feature of the more highly grafted IPNs. Polymer network II formed in the presence of linear polymer I results in morphologies dependent on the molecular weight of linear polymers. In the semi-2 IPNs, polymer I molecular weights below Mv = 20,000 caused polymer I to behave like a plasticizer or a diluent. The domain sizes of semi-2 IPNs agree with theoretical predictions developed by the present authors. |
