State of the art in recycling waste thermoplastics and thermosets and their applications in construction

Polymeric products such as plastics and rubbers are in widespread use, and the recycling of these polymeric materials has not kept pace with the increased production. There are serious environmental consequences to disposing of waste polymeric materials in landfills or incinerating them. Their low biodegradability makes it unpopular for both large and small industries to recycle them. This study reviews recycling strategies for waste thermoplastic and thermoset materials undertaken by industries and researchers. The primary objective is to review these techniques and identify those that can be applicable to the construction industry. There are three conclusions from this review: (1) Recycling of polymeric waste materials can be helpful to limit landfilled or incinerated waste plastic. (2) Proper selection of a recycling method for waste plastics and rubbers can effectively address the recycling problem without compromising the mechanical properties of the construction material. (3) The majority of the published articles in construction materials research have overlooked the importance of pre-treatment of waste polymeric materials to ensure compatibility with construction materials. Accordingly, there is an urgent need for understanding the science of functionalization of polymers to be able to tune surface properties of the recycled granules for targeted applications. This paper highlights critical research needs to facilitate the recycling of thermosets and thermoplastics to promote resource conservation and sustainability.