(274h) Impact of Reversible Deactivation Radical Polymerizations on the Gelation, Architecture, and Mechanical Properties of Polymer Networks: Insights from Mechanochemistry

Polymer networks are widely used in engineering and biomedical applications because they can sustain large reversible deformations. However, despite centuries of widespread use, their architecture and mechanical properties remain challenging to design through conventional synthetic methods. Specifically, these methods offer limited control over the kinetics and thermodynamics of gelation and, in turn, over the molecular connectivity of the networks.

In this talk, I will discuss the impact of Reversible Deactivation Radical Copolymerizations (RDRPs) on the kinetics of gelation and the architecture and mechanical properties of polymer networks. I will show that RDRPs lead to delayed gelation, phase separation, and softer and more extensible networks than conventional free radical copolymerizations. The reversible deactivation of radical chain ends during network growth slows the gelation rate and segregates the crosslinked network precursors (i.e., clusters) into monomer-rich and monomer-poor phases before complete gelation. These phases impact the load distribution among the polymers and, in turn, the size of the energy-dissipating region next to a crack. I will examine the size of this region through polymer mechanochemistry and provide guidelines for engineering the elasticity and fracture toughness of polymer networks, particularly at high temperatures or water concentrations when there is no viscoelasticity ahead of the crack.