Curing and thermo-mechanical studies of a modified thermosetting clearcoat containing OH-functional POSS nanocages

Abstract

Abstract This paper attempts to study the chemical, thermo-mechanical and rheological properties of an acrylic/melamine clearcoat modified with a polyhedral oligomeric silsesquioxane (POSS) macromolecule. OH-functional groups of the linear acrylic resin were stoichiometrically substituted with those of the POSS. This modification resulted in a drop in viscosity compared with the pristine sample, mainly because of the globular compact structure of the modifier. This lowered the chain entanglements and provided more mobile functional groups during curing. FTIR spectroscopy, dynamic mechanical thermal analysis (DMTA) and transmission electron microscopy (TEM) techniques were utilized to study the resultant clearcoats. It was illustrated that reduced viscosity facilitated curing reactions and lead to a more efficient and more extensive curing degree, leading to an enhanced cross-linking density in presence of the POSS nanostructure. It was also illustrated that compatibility of POSS and acrylic/melamine lead to a molecular-scale dispersion of POSS nanostructures within the matrix.