A Critical Review on The Feasibility of Recycled Polyethylene Terephthalate (PET) in The Production of Plastic Lumber.

The Global upsurge in plastic waste generation, which accounts for more than 8 billion metric tonnes, calls for innovative recycling solutions. Recently, the construction industry has been searching for durable, low-maintenance, eco-friendly, and sustainable alternatives to traditional materials such as wood, which is subject to decay and leads to deforestation. This review synthesizes the existing literature to critically evaluate the feasibility of using recycled PET (rPET) as a feedstock for producing structural-grade plastic lumber. This can provide a dual-benefit approach to waste management and the green economy. Although plastic lumber utilizes high-density polyethylene (HDPE), rPET possesses superior mechanical properties, such as higher tensile strength and flexural modulus. This study thoroughly examines the material characteristics of rPET, prevailing recycling processes, and the performance of rPET-based composites in comparison with incumbent materials. This highlights that rPET lumber demonstrates significant promise but faces challenges related to impact resistance, long-term durability, and a lack of standardized structural design guidelines. This review also identifies critical research gaps, such as the need for long-term creep and fatigue data, optimization of hybrid composites, and site-specific life cycle assessments, particularly in the Indian context. The findings indicate that with targeted research and development, rPET plastic lumber can transition from a niche, non-structural product to a reliable, high-performance construction material, thereby advancing the principles of a circular economy.