Synthesis and characterization of elastomeric polyuretrane/montmorillonite nanocomposites

A novel elastomeric polyurethane/montmorillonite nanocomposite based on poly(propylene glycol) 4,4'-diphenylmethane diisocynate and 1,4-butanediol was synthesized by intercalative polymerization technology. Octadecylamine was used as swelling agents to treat Na- montmorillonite and form organomontmorillonite through ion exchange. Nanoscale dispersing of clay in the nanocomposite was analyzed by X-ray diffraction and Molau experiment. At the same time, X-ray diffraction result showed that the intercalated nanocomposites were formed. Hydrogen bonding in the hard segments of the synthesized polyurethane/montmorillonite nanocomposite was found to decrease with the increasing amount of montmorillonite, but reached a minimum at 5 wt% montmorillonite concentration, as was evidenced by FTIR studies. DMA and DSC results showed that the glass transition temperature was reduced with increasing of montmorillonite concentration. Introducing 3% organomontmorillonite in the composites resulted in a 45% increase in the tensile strength and a 35% increase in the elongation as compared to thoee of pure PU.