Silicone Rubber Tack II: The Time-Dependent Autohesion for Symmetric Rubber-Rubber Contacts

The autohesion data are gathered for poly(dimethyl siloxane) (PDMS) with different molecular weights. The influence of molecular weight of the polymer is very pronounced. The data are interpreted on basis of the Wool-deGennes reptation theory; the application of first order kinetics of wetting is also tested. PDMS with a molecular weight only partially permitting the formation of entanglements exhibits a remarkably different and unusual behavior compared with the high molecular weight polymers. The latter develop tack in the form of logarithmic type curves, while the former show the presence of local maxima in the tack-time curves.