Preparation and characterisations of maleic anhydride-modified-(asphalt, natural rubber, and polystyrene) blends containing sand aggregate

Asphalt has been used extensively for road construction material as sand and gravel aggregates adhesive, although the elasticity of the material is inferior, which causing crack under repeating forces. Previous work in our group has blended polystyrene (PS) and natural rubber (NR; SIR-10), using reflux technique in toluene solution for 60 minutes under mechanical stirring for sand aggregate binder, in which optimum mechanical properties were found when used weight ratio of NR/PS/Sand: 18/12/70. In this work asphalt was added and (at various loading ratio: 30, 27, 24, 21, 18, 15) into the polystyrene and natural rubber blends in the presence of maleic anhydride (MA) and benzoyl peroxide (BPO) as modifier and initiator, using similar technique. The mixtures were then compression moulded at room temperature to produce three point bending test specimens according to ASTM D790-2 and dried under vacuum at 60°C to constant weight. It was found that (NR/PS/Asphalt/Sand: 9/6/15/70) is the optimum composition with MoE was 77.21 MPa and MoR was 92.65 MPa. This results were supported by data of FTIR spectroscopy, i.e., appearance of carbonyl peak of MA modifier at 1705,07 cm−1. DSC data of the optimum sample showed almost similar decomposition temperature (461°C), when compared to that without asphalt (465°C), whereas SEM micrograph of the sample showed homogenous distribution of sand aggregate in the blend.