A research team from the Universities of Bath and Surrey has developed a method to introduce degradable bonds into thermoset polymers, making them more susceptible to recycling.
A team of British scientists developed thermoset plastics such as gels, rubbers and elastomers, which are easier to recycle, which can degrade and reform without losing functionality.
With this development, the team explained, progress is made in facilitating the recycling of various types of plastics, including those considered difficult to recycle, such as rubber, gels and adhesives.
Thermoplastics and thermostables
There are two main categories of plastics: thermoplastics and thermosets, both made up of long chains of molecules called polymers. However, their behavior differs when subjected to heat.
Thermoplastics can be heated to high temperatures, molded as needed and cooled to the desired shape. Although they can be melted and transformed when recycled, they often break when stretched or stressed.
In contrast, thermoset plastics have cross-linked polymer chains that form a strong, flexible network. Although they are used in various products such as composite materials, paints and rubbers, their cross-links make them difficult to decompose and recycle, as they tend to burn rather than melt when heated.
Thermostable plastics that are easier to recycle
A research team from the Universities of Bath and Surrey has developed a method to introduce degradable bonds into thermoset polymers, making them more susceptible to recycling.
In a paper published in Polymer Chemistry, researchers detail the fabrication of polymer gels with breakable bonds incorporated into different parts of the structure. After degrading and reforming the gels, they observed that those with breakable bonds better retained their properties compared to polymers that broke through cross-linked bonds.
A development that can improve the recyclability of plastics
Scientists aim to apply this approach to other types of polymers, such as adhesives, sealants and elastomers. Dr Maciek Kopeć, from the Department of Chemistry at the University of Bath, said making bonds in thermoset materials reversible will broaden their applications and improve their recyclability.
The research team aims to establish a roadmap for the optimal placement of these breakable bonds, understand the reasons behind the ease of breaking some bonds, and optimize the system using other commercial polymers.
Additionally, they explore additional applications, such as the use of cross-linked polymers in controlled drug delivery systems.
