utilization of recycled polypropylene reinforced with graphene grown on polyaniline in 3d printing for comprehensive waste management

Sustainable management of polymer waste and its reuse in the form of value-added products is one of the key approaches in the circular economy. in this study, recycled polypropylene (rpp) was selected as the base material and reinforced with a graphene–polyaniline (g-pani) nanohybrid to improve its mechanical, thermal, and processability properties for 3d printing. the g-pani nanohybrid was synthesized via oxidative polymerization followed by final thermal reduction to form graphene layers. results showed that adding only 0.5–1 wt% g-pani to rpp increased tensile strength by up to 25%, enhanced modulus by 30%, and reduced thermal shrinkage during printing by 18%. thermal conductivity analysis also demonstrated that the g-pani composite created effective heat transfer pathways, improving the dimensional stability of the printed parts under thermal stress. to demonstrate a practical application in the construction sector, this nanocomposite was used to fabricate cold and hot water pipe fittings via 3d printing. these findings indicate that using rpp–g-pani can provide a sustainable, cost-effective, and environmentally friendly approach for producing 3d-printed construction structures and equipment.