A Dynamic Method for the Residual Stress Measurement During Polymer Crystallization

A new dynamic method based on bilayer system is proposed to characterize the residual stress formation during the crystallization of semi-crystalline polyethylene glycol 10000 (PEG10000). The resin is coated on a solid polymeric film to create a filmsubstrate compound. Its temperature field and dynamic deflection are monitored by synchronized optical and thermography cameras. The crystallization kinetics is first characterized from the former information. Then a simple dynamic model is proposed to relate the dynamic deflection with crystallization process. Residual stresses are established and in the range of 0–2.1 MPa. The generation of residual stresses is due to the edge constraints of the cantilever beam and to the increase of viscosity during solidification that allows the polymer to carry tensile loadings. The spherulite impingement is found to be important for this period from a microscopic view. Boundary condition should be well controlled to steer residual stresses. Such method is promising to measure residual stresses at the micro-scale for polymers to be spread on a flexible substrate and can mimic different mechanical situations of interest.