(391b) Multiscale Modeling for Nanoclearcoat Curing

Song, H., Wayne State University
Xiao, J., Soochow University
Huang, Y., Wayne State University

Nanocomposite materials, if applied properly, can demonstrate significantly improved performance and/or new functionalities of the resulting coating layers, such as surface texture alteration control, self-healing, and toxic chemical/acid/corrosive agent repelling.  Nanopaint is such a type of nanomaterials, which is being seriously evaluated in the coating industries.  A key nanocoating development step is the curing process.  As a nanoparticle-incorporated polymer material, four types of complex operational phenomena occur in a multistage curing process: heat transfer from the curing environment to the coating material, solvent and/or water evaporation, coating layer thickness change, and cross-linking reaction.  Fundamental questions on nanocoating curing are as follows: (i) how much will the presence of nanoparticles of different sizes and volume fractionsaffect the solvent removal and curing performance, (ii) how much will the nanocoating curing will affect energy consumption, and  (iii) how can we correlate the coating microstructure to the coating macroscopic quality?

In this paper, we introduce an integrated multiscale modeling approach to investigate the mechanisms of multistage heat and mass transfer, and chemical reaction kinetics at the presence of nanoparticles in the coating material during curing, which is a reactive drying process.  The effect of the size of nanoparticle and the composition of nanoclearcoat on solvent evaporation, cross-linking reaction, process efficiency and product quality are studied at different time-length scales. It is demonstrated that the integrated model can provide a thorough analysis of drying/curing operations, guide the design of nanocoating materials, and form the basis for developing optimal operational strategies for improving coating quality and reducing defects.  Model-based simulation also provides an opportunity to optimize the reactive drying process, where product quality and process efficiency goals can be achieved simultaneously.