Rheological Investigation of the Gel Time and Shrinkage in Hybrid Organic/inorganic UV Curable Films

Inorganic silane oligomer based on tetraethoxysilane was synthesized via sol-gel under acidic condition. UV curable organic-inorganic hybrid coatings were then prepared using the synthesized inorganic oligomers and tetraethylene glycol diacrylate. The effect of organic/inorganic content ratio on gelation and shrinkage of samples was investigated by photorheometry. It was revealed that incorporating higher amount of inorganic component in the samples improves the system mobility and postpones gelation. It also reduces the final film shrinkage that is stemmed from photopolymerization induced phase separation.