The processing of polymer matrix composites requires the formation of an autohesive bond between the surfaces of adjacent polymer entities as well as with the fiber surface. This autohesive bond strength development in amorphous polymers has been extensively studied and modeled. This paper describes a study undertaken to describe the development of the autohesive bond between polymer surfaces in semi-crystalline matrix composites. The results show that the development of the autohesive bond competes with the formation of crystals and actually results in the decrease of fracture strength at long processing times.