Microstructural rearrangements of 4,4′- methelenebis(phenyl isocyanate) (MDI) based polyurethanes in the presence of UV radiation

Abstract

MDI based polyurethanes have vast variety of applications. Its applications will be broaden with an understanding of the microstructural changes in the polymer matrix due to UV exposure. In this study the fluorescence analysis has been used to uncover the microstructural changes of polymer matrix in a UV environment. When this polymer is exposed to UV radiation hard segments crystallize and the process is assisted localized melting. When the UV exposure was ceased molecules re-arrange back to their initial structure due to the tensile forces originating from softsegment crystallization. However, tensile forces are not strong enough for a complete recovery of the micro structure. Residual solvent molecules can also disturb the recovery.