RESUMEN
This paper reports the scaling laws to describe the time-evolution behavior of solvent-mediated strength at the interface between two identical thermoplastic polymers below the glass-transition temperature. Our results suggest that the evolution scales as sqrt[t], where t is the curing time. It depends on the time evolution of interfacial stiffness and toughness, each of which scales as sqrt[t]. Employing a combination of experiments and continuum scale simulations, we show that the evolution of strength, stiffness, and toughness is controlled by pure diffusion. It can therefore be treated as a Gaussian process. While the "saturation of strength," which describes the transition of strength evolution into a steady state, does not strictly follow any power-law type behavior, a simple exponential law accurately characterizes both evolution and saturation of strength. This suggests that the longer timescale nonlinear processes (that are overdetermined by the power-law type scaling laws) diminish rapidly in approaching a steady state. Furthermore, the kinetics of the evolution processes is well captured by the dissolution of polymer particles. While dissolution involves a different timescale, it strongly correlates with the solvent-welding process upon normalization. The correlation highlights the equivalence of the dissolution and solvent-joining processes and offers an easier route to determining strength at arbitrary curing times. Additionally, the dissolution rate of polymer particles is shape dependent and governed by the surface-to-volume ratio.
