مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

According to the crystallization conditions, polypropylene (PP) can be crystallized into three forms: a-monoclinic, 13-hexagonal, and v-form. The major problem with thermoforming of PP is its narrow processing window. Due to broadening the melting region, 13-crystal form has a significant effect on the thermoformability of PP. In this study y-quinacridone (Q-dye) was used as a 13-nucleator agent. Three different concentrations of Q-dye (5, 10, and 50 ppm) were mixed separately with PP by a laboratory twin screw extruder. X-ray graphs confirmed the 13-nucleating effect of Q-dye obviously. Differential scanning calorimetry (DSC) was used For evaluating of the crystallization behaviour. Both melting points of a-and 13-crystals were seen in the samples containing Q-dye. Crystallization temperature and the rate and degree of crystallinity increase with 13-nucleator concentration. Sagging tests were carried out at 170°C and it was observed that sag distance and sagging rate decreased with increasing Q-dye content.