Effect of blend ratio on properties of natural rubber/low density polyethylene blends

Abstract

Thermoplastic natural rubber (TPNR) those produced by blending of thermoplastics and natural rubber using traditional internal mixers and plastic extruders, are becoming increasingly accepted in the global polymer market. Natural rubber (NR)/low density polyethylene (LDPE) blend is used as a TPNR in the manufacture of rubber based articles. These blends can best be appreciated as high impact resistant engineering materials and The main objective of this study was to investigate the effect of blend ratio on physical, chemical and mechanical properties of NR/LDPE blends. In this study, a series of simple blends was formulated by varying LDPE loading from 10 to 90 by wt. at 20% intervals. The blends were prepared using a Brabender Plasticorder by melt mixing at a temperature of 130 °C, and at a rotor speed of 60 rpm. Minimum torque of melt blending was investigated by a moving die rheometer while glass-transition temperature (Tg) of blends were measured by differential scanning calorimetry. Swelling behaviour studied by sol/gel analysis using toluene as the solvent, according to ISO standard. Physicomechanical properties were determined according to ISO standards. Minimum torque, which is an indication of the processability and of stock viscosity, decreased with increase in LDPE loading. Tear strength, tensile strength and hardness increased with increase in LDPE loading while elongation at break decreased. Glass-transition temperature, Tg of NR phase of the blends slightly varied with LDPE loading. Solvent resistance increased with increase in LDPE loading. These results indicate a phase change after 30 % by wt. of LDPE loading. Further, the results reveal that the blends with different properties required for different applications could be obtained by varying the blend ratio.