Modification of HBA/D230 Polymer for Stone Protection

By using poly(propylene glycol)bis(2-aminopropyl ether) (D230) as curing agent, we have prepared color-stable hydrogenated Bisphenol A (HBA) epoxy polymers, containing TiO₂ nanoparticles. The loading and size of TiO₂ nanoparticles (5 ~ 10, 21, 200 ~ 400 nm) are changed in order to investigate their photocatalytic effect on removing pollutants deposited on the surface of stone. HBA/D230 polymers containing different amounts of TiO₂ nanomaterials were applied to methyl orange (MeO) on the limestone with exposure to the dry and wet environment, respectively. The results showed that the modification of HBA by addition of titanium dioxide particles substantially not only enhanced its protective efficiency but also rendered the treated stone surface self-cleaning ability. The photocatalytic degradation effect of MeO at the concentration of 0.001 M was the best when the size of TiO₂ nanoparticles was between 200 ~ 400 nm. Compared to those in dry environment, the decrease of the content of MeO in samples exposed to wet environment was due to humidity on the surface of limestone.