Lesley-Ann O'Hare

Atmospheric Pressure Plasma Polymerised Primer to Promote Adhesion of Silicones

By combining a liquid primer and a plasma jet system, a new route to improved adhesion on various substrates has been developed. The liquid primer is introduced as an aerosol into a plasma jet and the resultant active species are deposited as a polymer coating on adjacent surfaces. Careful control of the plasma parameters produced a dry polymerised coating with functional chemistry designed to enhance the adhesion of silicone sealants to two substrates. This paper describes the surface chemistry and adhesion properties of various coatings on both a plastic and a metal substrate. Selected surface analysis techniques were coupled to both wet and dry adhesion testing to characterise the factors that control adhesion within the system. Mechanical testing indicates that adhesion was improved by several orders of magnitude.

Chapter 14 – Fundamental aspects of adhesion technology in silicones

Publisher Summary This chapter reviews the general structures and properties of silicone polymers. It describes the cross linking chemistry and the properties of the cross linked networks. It then discusses the promotion of adhesive and cohesive strength. The buildup of adhesion and the loss of adhesive strength are explained in the light of the fundamental theories of adhesion. The chapter illustrates the use of silicones in various adhesion applications and leads to the design of specific adhesive and sealant products. The surface of the substrate, the silicone/substrate interface, and the bulk properties of silicones play significant and influential roles that affect practical adhesion and the performance of the silicone. The design of silicone adhesives, sealants, coatings, encapsulants, or any products where adhesion property is needed requires the development chemist to have a thorough understanding of both silicone chemistry and adhesion phenomena. The chapter presents a detailed review of the theories that are proposed for the mechanisms of adhesion. The various theories underlying each mechanism is briefly outlined and qualitatively illustrated in the chapter with specific examples.