SURFACE MODIFICATION OF POLYCARBONATE BY GLOW DISCHARGE AND ITS EFFECT ON ADHESION

Abstract

The history of synthetic polymers started with the invention of rubber in 1839 by Charles Goodyear, but the most significant achievement took place after 1940, when the development of polymer industry began with the introduction of polymeric materials in diverse applications in automobiles, electronics, food packaging industries, building and other manufacturing industries. Generally, polymers are long chain molecules with bonds satisfying the valency. The surface energy of polymer is, therefore, low, creating problems in adhesive joining, coating, printing, formation of composites and similar other applications where polymers are to be integrated with other types of materials like metals or ceramics having relatively high surface energy. Integration of a material with another takes place easily through spontaneous creation of an interface of relatively lower energy by merger of two high energy surfaces, because of decrease in free energy. Surface modification of low surface energy polymers is, therefore, carried out with the objective of increasing the surface energy so that the formation of interface becomes energetically favourable. Unique properties of polymeric materials_such as_ high strength to weight ratio, resistance to corrosion, chemical inertness, flexibility in design and low cost make these materials increasingly more attractive over traditional materials, inviting attention to problems encountered in their diverse applications. Among many polymers, the polycarbonate (PC) is widely used due to its specific properties such as transparency, high strength, heat resistance, high electrical insulation and good dielectric properties. Further, it has excellent processability, biological inertness, recyclability and relatively lower cost.