Synthesis and characterization of poss-urethane and poss-urethane acrylate hybrids

Polyuretanes (PU) are polymers which are obtained by reaction of diisocyanates and polyols and are used in the production of many materials such as coatings, elastomers, foams and adhetives. Both isocyanates and polyols directly affect the chemical and physical properties of PUs. Recently, PU based materials with nanosized segments on the chain have attracted attention due to their superior properties. Polyhedral oligomeric silsesquioxanes (POSS) are nano-sized molecules from the silica-based inorganic core (Si₈O₁₂) located at the corners of eight organic groups which control the chain movement of the polymers they participate in at the molecular level and thus effectively strengthen the polymers. Whether the addition is physical or chemical, the resulting product has improved thermal stability, atmospheric strength, optical properties and combustion resistance. The purpose of this study, is to syhthesize of POSS macro-monomer bearing methacrylate functions, the preparation of UV curable hybrids and investigation of the physical and mechanical properties performance of the resulting hybrids. At the first step of the study synthesized octamercaptoproply-POSS (POSS-SH) from mercaptoproplytrimethoxysilane (MPT). By the reaction of –SH groups with the –NCO groups of 3-isocyanatoethylmethacrylate (IEM), octafunctionalized POSS-methacrylate macromonomer was successfully synthesized. Also, a polyurethane acrylate oligomer was synthesized from PEG-1500, isophorone diisocyanate and hydroxyethlymethacrylate. Hybrid formulations were cured using UV light. Thermal properties of the hybrids were investigated with thermogravimetric analyser and differantial scanning calorimetry and obtain to be significantly improved. With the increasing amount of POSS-methacrylate both mechanical properties and film performances improved.