Application of Taguchi method for optimization of mechanical properties of polyurethan /SiO2 nanocomposite on polypropylene for automotive clear coating

The purpose of this study was tocharacterize thepolyurethane (PU) nanocomposites based clearcoatusing standard Taguchi L9 method. The silica nanoparticle content, curing temperature, type of hardener, and flash-off time were regarded as factors.Nanocomposites characterized by scanning surface microscopy (SEM).Results showed that all PU nanocomposites were gloss in the range of 91-94 which confirms that the presence of silicananoparticles did not have an adverse impact on optical properties. Moreover, the most significant factor contributing to the hardness of samples was the silicananoparticle content. alsousing high amount of silicananoparticle (5 wt%) reduced the hardness of clearcoats due to interrupting curing process. The clearcoats performance after carwash test indeed showed that sample containing 2% silicananoparticle cured at 85oC with a mixture of hardener (50% biuret, 50% trimer) after flash-off time of 5 min had the optimum physical and optical properties.