Prompt Description

The oxidative scission of polybutadiene (PB) mid-blocks in SBS copolymers during long-term aging leads to the degradation of the elastic, physically cross-linked network. To mitigate this, a dual-rejuvenation system is employed. Diallyl phthalate (DAP) functions as a reactive plasticizer, rather than a conventional softener. Its unsaturated allyl groups participate in mild, thermally activated, radical-mediated reactions with the fractured SBS chain ends, promoting recombination and partial restoration of the three-dimensional polymer network. This chemical repair mechanism is distinct from and synergistic with the physical rejuvenation provided by sunflower oil (SO). SO primarily rebalances the colloidal structure by replenishing maltenes, resulting in a comprehensive recovery of both elasticity and flow properties in aged asphalt. A schematic illustrating both the physical capsule action and the chemical “dual rejuvenation” mechanism would be beneficial.