ABSTRACT
Unlike simple fl uids, polymers have very slow dynamics so that even relatively far away from their glass transition temperature, highly entangled polymer melts can diff use distances of the order of the coil size in minutes or more. Th is was recognized some time ago1 and spurred the creation of the so-called interdiff usion theory of adhesion, which stated that the adhesion between two polymers put in contact in melt increased with the square root of the contact time. However, almost all the studies on that topic focused on a situation in which the interface is formed in the melt state, but its mechanical strength is tested aft er the system is cooled, in its glassy state.2-5
In many industrial processing applications such as coextrusion, molding, elastomer processing prior to vulcanization, or pressure-sensitive bonding by tack, both interface formation and some mechanical strength build-up must occur in the melt state.6-9 For pressure-sensitive adhesives (PSAs), the substrate surface is oft en rigid and impenetrable to polymer chains, but in certain cases the PSA can be bonded to an elastomer surface, where chain interpenetration is a possibility.
