Polymer-Polymer Adhesion in Melt-Processed Layered Structures

摘要

Improving the adhesion of polyolefins to glassy polymers in complicated by the semicrystalline nature of the polyolefins.Traditional methods used in glassy polymers to in crease the interlayer adhesion,including the addition of a diblock copolymer or the formation of a copolymer through in situ reaction, are still successful with semicrystalline polymers.However,melt miscibility of the adhesion promoting molecules is no longer sufficient;they must also co-crystallize.Even when co-crystalization is achieved,the reactive method is shwon to provide greater fracture toughness than the addition of a pre-made diblock copolymer.In the tlatter case,the formation of micelles limits the efficiency of the diblock copolymer.Finally,significant adhesion enhancement is attainable in reactive systems with contact times as short as 45 seconds as demon-strated through a multilayer coextrusion of amorphous nylon against a polypropylene-maleated polypropylene blend.