Mechanical, thermal and accelerated weathering studies of bio-based polyurethane/clay nanocomposites coatings

Biobased polymer has taken tremendous attention in recent times. In the present study bio-based polyurethane have been synthesized from the vegetable oil i.e., dehydrated castor oil, 1,4-butanediol and isophorone diisocyanate in presence of a catalyst by solution polymerization method. Then polyurethane nanocomposites were synthesized using different amount of nanoclay (C30B) (1, 3 and 5 wt%). The synthesis of polyurethane and its nanocomposites were confirmed by FTIR and XRD analysis. The mechanical properties such as tensile strength (2.2-4.5 MPa), elongation at break (299%-435%) hardness (46-70) and abrasion resistance (351-201 mg/1,000 cycles) increased with the increase of nanoclay content. The initial thermal degradation temperature found to increase from (220 to 290 degrees C) with the increase of nanoclay content in the nanocomposites. The nano-clay was interacted with the hard segment of the matrix polymer as reflected from the atomic force microscopy studies. Weathering study revealed that nanocomposites have higher weather resistance capacity than pristine polyurethane. It can be concluded that the prepared nanocomposites might be good outdoor topcoat materials.