Chapter 6 - Structure-Property Relationships

Abstract

Structure–property relationships of highly cross-linked ultraviolet (UV) curable duromers have been evaluated for many different systems. A review of characterization methods and understanding of the relationships among exposure conditions, chemical structure, and network properties are given by Zumbrunn. Increasing the monomer (diluent or resin) functionality leads to higher cure speed, higher Tg, higher cross-link density, higher hardness, and higher chemical and scratch resistance but lower flexibility and lower conversion, causing a higher content of uncured residual unsaturated groups. Mechanical properties relevant for coatings are hardness, stiffness, toughness, elasticity, and many others. All these properties are not only material properties, but they also depend on the molecular interactions, morphological structures (amorphous or crystalline) as well as the processing conditions. For linear polymers, a lot of data exist characterizing the structural influences on mechanical properties, however, much less data exist for cross-linked coatings. And even less data are available for correlating property–property relationships like the influences of mechanical properties on scratch resistance, pendulum hardness, elasticity, or Taber abrasion.