Investigating Viscoelastic Behavior of Resins, Organic Coatings and Nanocomposites

Most organic coatings obtained from commercial paint and coating products are viscoelastic. The study of the viscoelastic behavior of these coatings after curing is one of the important tests that provide useful information on the performance of the cured coating. In this paper the viscoelastic properties of resins, coatings and their nanocomposites using the dynamic mechanical thermal analysis (DMTA) is investigated. With DMTA, the values of storage modulus, loss modulus and also the loss term as a function of temperature or frequency are obtained. DMTA is a useful method for investigating the polymer structure, such as the average molecular weight of the cross-linked chains, cross-link density, the homogeneity or heterogeneity of the cross-linked resins, the degree of incompatibility in the resin composition, the distribution of nanoparticles in the resin matrix. Also different physical quantities such as gelatinization point, glass transition temperature, cross-link density, curing conversion percentage, minimum viscosity during curing process, energy of activation of glass transition temperature, brittleness coefficient, displacement coefficient in the William-Lundley-Fry (WLF) relation and investigation of α, β and γ transitions are investigated using DMTA.