Investigation of functional, physical, mechanical and thermal properties of TiO2 embedded polyester hybrid composites: A design of experiment (DoE) study

This paper presents a study on the Design of Experiments (DoE) approach to optimize the fabrication parameters of titania (TiO₂) embedded glass fiber reinforced polyester hybrid composites (HCs). HCs of unsaturated polyester resin (UPR) were fabricated using methyl ethyl ketone peroxide (MEKP) as the curing agent by hand lay-up process (HLUP) and compression molding technique (CMT). The fabrication parameters were optimized by Taguchi DoE (an orthogonal array of L₂₅) using 3 control factors (concentration of TiO₂, concentration of MEKP and curing temperature) having 5 levels each. Statistical tools were employed to identify significant factors affecting tensile strengths and its reproducibility during HLUP. It was found that the concentration of TiO₂ in HCs significantly influenced the tensile strength (TS) followed by MEKP concentration and curing temperature. The highest value of TS was obtained at 3?wt% TiO₂, 2?wt% MEKP and 80?°C. Nevertheless, the sensitivity of TiO₂ concentration was basis for fabrication of polyester titania glass fiber hybrids (PTGFHs), which were further investigated for density and void fractions, linear shrinkage, flexural strength, impact strength, hardness and thermal behaviors. Moreover, cross-linking and hydrogen-bonding between polymeric chains, styrene, silica content of glass fiber and TiO₂ particles in PTGFHs were confirmed by Fourier transform infrared spectroscopy.