1978 Volume 35 Issue 12 Pages 759-764
Short-time (30ms) adhesion of Nylon 12 was examined from the view point of the diffusion properties of polymer molecules. Diffusion coefficients DA of Nylon 12 in melt, which were measured by the microspectrophotometry using a dye-tagging technique, showed much larger values than the bulk diffusion coefficients DB which were estimated from melt viscosity and seemed to correspond to the self-diffusion coefficients of molten Nylon 12 molecules. Apparent activation energy for diffusion EDA was much smaller than that for viscous flow Eη or EDB. Molecular weight dependence of DA was weaker than that of DB. The diffusion behavior suggests that the short-time adhesion of these polymer films is accounted for the segmental diffusion of Nylon 12 chains. This was also supported by the similar behavior observed in the local diffusion coefficients DL which were estimated from the fluorescence depolarization measurement for molten Nylon 12. The behavior of lap shear strength of Nylon 12 laminated on steel plate conducted for the short-time and the moderate time (120s) adhesion was consistent with the molecular mechanism.
