Mechanical and thermal studies on modified 50/50 natural rubber latex/poly(styrene-block-isoprene-block-styrene) blend by gamma irradiation and comparison with sulphur and peroxide vulcanization methods

The gamma irradiation offers high penetration depth and fast crosslinking process. This work investigates the influence of various gamma irradiation doses on a blend consists of 50 wt% natural rubber latex (NRL) and 50 wt% poly(styrene-block-isoprene-block-styrene) (SIS). The blends are irradiated under doses ranged from 4 to 16 kGy. The irradiation process at low dose (12 kGy) has resulted in higher tensile strength (4.34 MPa), elongation at break (1622.10%) and crosslink density (9.72 × 10−5 mol/cm3) in 50NRL/50SIS blend compared to blends prepared from sulphur and peroxide vulcanizations. The degradation temperature of 50NRL/50SIS-12 kGy blend was slightly increased (470.57 °C) with a C–C band at 930 cm−1 and a NR crystal peak at 31.2° were observed. The irradiation process has increased the surface roughness of 50NRL/50SIS blend, shown by atomic force microscopy. To conclude, these results revealed that by effectively control the irradiation dose, the crosslinking in the 50NRL/50SIS blend can be tailored.