Transesterification‐vulcanization route to durable composites from post‐consumer poly(ethylene terephthalate), terpenoids, and industrial waste sulfur

Abstract

AbstractDespite improvements in chemical recycling, most post‐consumer plastics are still deposited in landfills where they pose a significant threat to ecological health. Herein we report a two‐stage method for chemically recycling poly(ethylene terephthalate) (PET) using terpenoids and waste sulfur to yield composites. In this method, post‐consumer PET (from beverage bottles) undergoes transesterification with a terpenoid alcohol (citronellol or geraniol) to yield low‐molecular PET oligomers. The terpene‐derived alkenes in these PET oligomer derivatives then served as reaction sites for inverse vulcanization with 90 wt% elemental sulfur to form composite CPS (using citronellol) or GPS (using geraniol). Composition, mechanical, thermal, and morphological properties were characterized by NMR spectroscopy, MALDI, FT‐IR spectroscopy, compressive and flexural strength analysis, TGA, DSC, elemental analysis, and SEM/EDX. The composites CPS (compressive strength = 5.20 MPa, flexural strength = 3.10 MPa) and GPS (compressive strength = 5.8 MPa, flexural strength = 2.77 MPa) showed mechanical strengths comparable to those of commercial bricks (classification C62 for general building). The approach delineated herein thus represents a method to chemically recycle waste plastic with industrial waste sulfur and plant‐derived terpenoids to yield composites having favorable properties comparable to existing building materials.