A Comparative Study of the Effect of Degradation on the Properties of PP/NR and PP/RR Blends

Abstract

The effect of various degradations on the tensile and morphological properties of polypropylene (PP)/natural rubber (NR) and PP/recycle rubber (RR) blends at different rubber content were studied. The blends were melt mixed using a Brabender Plasticorder torque rheometer at 190°C and 50 rpm. All blends were exposed at three different conditions, i.e., heated in oven (100°C) for 24 hrs, immersed in distilled water (90°C) for 24 hrs, and immersed in ASTM oil No. 3 for 70 hrs. The results indicated that at a similar rubber content and degradation condition, PP/RR blends exhibit a higher percentage of retention of tensile strength and Young's modulus but a lower elongation at break than PP/NR blends. Scanning electron microscopy (SEM) examination of the tensile fracture surface of PP/NR blends indicates a smooth fracture surface than PP/RR blends after thermo-oxidative aging. This observation supports the higher retention of tensile strength after thermo-oxidative aging of PP/RR blends than PP/NR blends. Thermogravimetric analysis of both blends show that the thermal stability of PP/RR blends is higher than that of PP/NR blends.

Keywords:

• Degradation
• Polypropylene
• Natural rubber
• Recycle rubber