Supervisor: Dr. Bronco Simona
Title: Synthesis and characterization of nanocomposite based on polyurethanes ionomer matrices
Abstract: Nowadays energy conservation is an important factor that could be reached in house and building, for example thanks to the development of windows with nanocomposite coating acting as solar shield and heat insulator.
This work concerns about synthesis and characterization of nanocomposite materials as glass coating for energy saving application. The target is the preparation of materials composed by ionomeric polyurethanes filled with mixed oxides of antimony and tin (ATO, SnO2:Sb2O3). Polymeric matrices are based on linear thermoplastic polyurethanes formed by hard (aromatic diisocyanate) and soft segments (poly tetramethylen oxide). They have been synthesized through a two steps synthesis: in the first one diisocyanates and diols react to give the prepolymer –NCO terminated; in the second step, the prepolymer reacts with a suitable chain extensor.
Three different kind of chain extensor are used, in order to obtain cationic and anionic polyurethanes. In particular, cationomer polyurethanes (PUC) are synthesized via a quaternarization reaction of nitrogen atoms of extensor, while anionic polyurethanes (PUA) are synthesized through ionization reaction of carboxylic groups of extensor. A different class of cationic polyurethanes (PUI) are formed directly using an extensor bearing two cationic charges in the chain backbone.
Ionic charge on polyurethanes is exploited to create water polymeric emulsion, in order to avoid the use of organic solvent in the final application as coating. Ionic charge could also stabilize inorganic nanoparticles. In particular, polyurethanes are modified with ATO nanoparticles, that are known to have isolation properties toward NIR radiation [2].
Materials are synthesized varying hard/soft ratio, percentage of ionic content and percentage of ATO nanoparticles.