Effect of the Microstructure of a Hyperbranched Polymer and Nanoclay Loading on the Morphology and Properties of Novel Polyurethane Nanocomposites

Novel, polyurethane nanocomposites based on toluene diisocyanate, poly(propylene glycol), various hyperbranched polymers (HBPs), and layered silicate were loading and the functionality of HBP on the structure and properties of polyurethane nanocomposites. The microstructure of the nanocomposites was investigated by X-ray diffraction analysis and high resolution transmission electron microscopy. It was found that exfoliated morphology and good dispersion were obtained up to 8 phr clay loading for all of the nanocomposites: similar to 100% increment in tensile strength, similar to 2 fold increase in the lap shear strength similar to 200% increment in the peel strength, and 120% increment in the storage modulus along with a dramatic improvement in thermal stability were observed with the addition of 8 Phr clay over the pristine polyurethane. The higher the level of functionality of the HBP, the higher is the property enhancement. These properties were correlated with the state of dispersion of clay platelets in the polyurethane matrix, the structure of the matrix, and clay-polymer interaction.