A New Phenomenon: Sub-Tg, Solid-State, Plasticity-Induced Bonding in Polymers

TL;DR

This paper reports a novel sub-Tg, solid-state bonding mechanism in polymers where plastic deformation induces molecular mobility, enabling rapid adhesion at temperatures well below Tg, expanding understanding of polymer bonding processes.

Contribution

The study introduces a new sub-Tg, plasticity-induced bonding phenomenon in polymers, demonstrating rapid solid-state adhesion driven by plastic deformation at ambient temperatures.

Findings

Bonding occurs within seconds at sub-Tg temperatures.

Plastic deformation facilitates molecular interpenetration and adhesion.

No bonding observed without plastic flow, confirming its essential role.

Abstract

Polymer self-adhesion due to the interdiffusion of macromolecules has been an active area of research for several decades [70, 43, 62, 42, 72, 73, 41]. Here, we report a new phenomenon of sub-Tg, solid-state, plasticity-induced bonding; where amorphous polymeric films were bonded together in a period of time on the order of a second in the solid-state at ambient temperatures nearly 60 K below their glass transition temperature (Tg) by subjecting them to active plastic deformation. Despite the glassy regime, the bulk plastic deformation triggered the requisite molecular mobility of the polymer chains, causing interpenetration across the interfaces held in contact. Quantitative levels of adhesion and the morphologies of the fractured interfaces validated the sub-Tg, plasticity-induced, molecular mobilization causing bonding. No-bonding outcomes (i) during the compression of films in a near hydrostatic setting (which inhibited plastic flow) and (ii) between an 'elastic' and a 'plastic' film further established the explicit role of plastic deformation in this newly reported sub-Tg solid-state bonding .