Viscoelastic properties of alkyd ceramers

The viscoelastic behavior of three alkyd ceramers was studied using dynamic mechanical thermal analysis (DMTA). A commercial product was compared to m odel alkyds. The model alkyds were prepared from phthalic anhydride, glycer ol, and linseed or sunflower seed oil. Three sol-gel precursors, titanium t etra-i-propoxide, titanium di-i-propoxide diacetylacetonate, and zirconium tera-n-propoxide were investigated. The alkyd ceramers were evaluated as a function of both alkyd type and a sol-gel precursor content. The viscoelast ic data showed that both E' and T-g were affected by sol-gel precursor cont ent. Both the crosslink density and T-g demonstrated a minimum at low sol-g el precursor contents. After this minimum, both the crosslink density and t he T-g increased substantially. (C) 1999 John Wiley & Sons, Inc.