CALCULATION OF STRESSES IN CROSS-LINKING POLYMERS

A general constitutive model is presented for calculating the evolutio n of stresses in crosslinking polymers. The analysis is valid for ther mo- and chemo-rheologically simple polymers and for time-dependent str ain histories where the total strain at any time is not large, such th at linear viscoelasticity applies. We identify the material parameters required and outline experimental and theoretical methods for their d etermination. This formalism is then used to calculate the development of cure stresses for an epoxy wherein the glass transition temperatur e exceeds the cure temperature during the reaction. Finally, we discus s practical methods of stress minimization through control of the cure cycle.