# Modulation of Depolymerizable Poly(thioether-thioester) Properties in Reversible Covalent Composites

## TL;DR

Scientists created a recyclable plastic using a special polymer composite that can be broken down and reused while maintaining its properties.

## Contribution

A new recyclable polymer composite system with tunable properties and reliable depolymerization and repolymerization processes is introduced.

## Key findings

- The composite's thermal and mechanical properties can be adjusted by varying particle amounts.
- The material can be 3D printed and depolymerized to recover monomers for reuse.
- Repolymerized material retains mechanical properties similar to the original composite.

## Abstract

We incorporated thiol-functionalized silica particles
as macroinitiators
for the construction of composites by ring-opening polymerization
of thiolactones. A separate photochemical cross-linking step was employed
to enhance the stability of the polymer composite material. The thermal
and mechanical properties of the materials can be tuned by varying
the amount of particles, and a representative formulation could be
3D printed. The polymer composite was depolymerized in the presence
of a catalytic amount of thiol and 1,8-diazabicyclo(5.4.0)­undec-7-ene
(DBU) base to recover substantial amounts of monomer, which were repolymerized
and photo-cross-linked to give a material very similar in mechanical
properties to the virgin composite. The modular nature of this system
and the reliability of the bond-forming and bond-breaking steps suggest
that it may prove to be useful as a new type of recyclable plastic.