DUAL CURE INTERPENETRATING POLYMER NETWORKS FOR BONDED COMPOSITE ASSEMBLIES

Composite parts are typically secondarily bonded to produce composite assemblies. However, dual cure systems can be partially cured to produce parts with handling strength while retaining the ability to produce primary bonds during composite assembly. In this research, an acrylate-epoxy interpenetrating polymer network (IPN) was investigated as the matrix material for continuous fiber composite materials. The IPN can cure as either a sequential or simultaneous IPN. When partially cured in sequential fashion with UV radiation, the composite develops handling strength. Adhesive casts demonstrated a 24 MPa tensile strength while full thermal cure demonstrated a 77 MPa tensile strength. Double lap shear results show a 40 percent increase in shear strength for partially cured IPNs that were co-cured with the lap splices as compared to identical lap splices co-bonded to a fully cured IPN laminate.