Use of the Taguchi Method for Optimization of Poly (Butylene Terephthalate) and Poly (Trimethylene Terephthalate) Blends through Injection Molding

Abstract

Abstract A statistical experimental design method known as the Taguchi method was utilized to optimize the injection molding processes of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) blends. Impact strength was taken as the optimized property. The significant parameters included mold temperature, injection pressure, holding pressure, injection time and holding temperature. Results of the Taguchi analysis gave mold temperatures as major influencing factor on the impact strength. The optimal processing conditions were determined through the Taguchi method giving an increase of 13.7% in impact strength for the blend. Further analysis was done to distinguish the blends dependency on temperature. Differential scanning calorimetry curves indicated the presence of recrystallization peaks that were dependent on the temperature profile the sample had received prior to testing. Polarized optical microscopy was used to show the different sphereulitic growth patterns under varying isothermal conditions. It was seen that at 90°C sphereulitic growth contained pockets of different sized spereulites. AFM imaging was also used to indicate differences in blended polymer morphology.