Abstract
This research examines the enhancement of petroleum tar through its modification with gossypol resin and secondary/recycled polypropylene (SPP), aiming to obtain a bituminous binder with superior physicochemical and performance characteristics. The modification procedure was implemented under strictly regulated thermo-mechanical regimes. Benzoyl peroxide was employed as a radical initiator to facilitate reactive coupling between polypropylene macromolecules and the functional groups intrinsic to gossypol resin. The resulting chemical transformations and microstructural reorganization were systematically characterized using Fourier-transform infrared spectroscopy and electron microscopy. Experimental findings indicate that the concurrent incorporation of gossypol resin and SPP induces the formation of a reinforced polymer–resin network enhances structural uniformity and contributes to the binder’s resistance to thermal and mechanical stresses. The proposed modification strategy presents a resource-efficient approach for valorizing polypropylene waste and provides a technologically and environmentally viable route for producing next-generation bituminous binders.