Interpenetrating polymer networks based on liquid natural rubber. 1. Synthesis and effect of nco/oh ratio on physical and mechanical properties

Interpenetrating polymer networks (IPNs) of polyurethane based on hydroxyterminated natural rubber with varying NCO/OH ratios and polystyrene were synthesized under different experimental conditions. These IPNs were found to make tough films. The IPNs were characterized by their physical, mechanical and morphological properties like density, Shore‐A hardness, crosslink density, tensile strength and elongation at break. The IPNs exhibited an increasing trend in density, Shore‐A hardness and tensile strength with increasing polystyrene content, while elongation at break decreased with similar variation in polystyrene content. The crosslink density measurements indicated a possible phase inversion process.