# Dynamic Thiol–ene Polymer Networks Enabled by Bifunctional Silyl Ether Exchange

## TL;DR

This paper introduces a new type of dynamic polymer network that can be reprocessed and degraded, offering a sustainable alternative to traditional plastics.

## Contribution

The novel use of bifunctional silyl ether alkene cross-linkers in thiol–ene click chemistry to create tunable dynamic polymer networks.

## Key findings

- Viscoelastic properties can be adjusted by up to three orders of magnitude through catalyst loading and cross-linker modifications.
- Stress relaxation kinetics show a nonmonotonic relationship with cross-linker length.
- The polymer networks retain mechanical integrity after three reprocessing cycles and can be fully degraded with an acid catalyst.

## Abstract

Dynamic polymer networks bridge the gap between traditional
thermoplastics
and thermosets, representing an avenue toward sustainable polymer
synthesis. In this study, we utilize photoinitiated thiol–ene
click chemistry to synthesize dynamic polymer networks through incorporating
a series of bifunctional silyl ether alkene cross-linkers in the presence
of catalytic p-toluene sulfonic acid. We demonstrate
that the viscoelastic properties of the material, represented by its
stress relaxation time constant, can be manipulated by up to 3 orders
of magnitude by simple modifications in catalyst loading, amount of
silyl ether cross-linker present, and/or dynamic cross-linker length.
Our results show that a nonmonotonic relationship exists between stress
relaxation kinetics and cross-linker length. Two representative networks
were chosen to illustrate reprocessability under mild temperature
conditions. These networks exhibited no loss of mechanical integrity
after three reprocessing cycles. The networks can also be fully degraded
in the presence of an excess of an acid catalyst.