Two-dimensional heat transfer analyses for non-isothermal molding of amorphous thermoplastic polymers and composites are presented. Solutions of the heat transfer analyses were obtained using the finite element technique, which includes convec tive heat transfer from the boundaries of the specimens. A non-isothermal autohesion model was developed by coupling the heat transfer analyses with an isothermal autohesion model for Udel P1700 polysulfone. The resulting computer code allows prediction of the time required for crack healing in amorphous polymers and autohesive bonding of the ply interfaces of fiber-reinforced composites under non-isothermal processing conditions. Results of the model are compared with data obtained during crack healing of Udel P1700 compact tension specimens and compression molding of 64-ply graphite/polysulfone com posites. Agreement between the model and data was good.

The double cantilevered beam (DCB) Mode I fracture toughness test was selected to characterize the interply (autohesive) bonding of the prepreg plies during thermoplastic composite consolidation. AS4 graphite fiber/P1700 polysulfone amorphous thermoplastic prepreg was selected for study. The fractured AS4/P1700 DCB specimens were healed in a special fixture under different combinations of temperature, pressure, and time. The healed DCB specimens were refractured and the critical strain energy release rates ( G IC ) were measured. Pressure was found to be a key factor governing the healing process. Temperature and time dependencies of the interply bond development were also observed.