Dilatational-Plasticity Opens a New Mechanistic Pathway for Macromolecular Transport Across Polymeric Interfaces Yielding Solid-State Bonding

TL;DR

This paper introduces a novel solid-state polymer bonding mechanism driven by mechanical deformation, enabling rapid interfacial interpenetration and entanglement at temperatures below the glass transition, as revealed by molecular simulations.

Contribution

It uncovers a new mechanistic pathway for polymer bonding via plastic deformation-induced molecular mobility, bypassing traditional diffusion processes.

Findings

Plastic deformation causes chain interpenetration at sub-glass transition temperatures.

Enhanced dilatation and densification facilitate molecular mobility and bonding.

New bonding method is faster and less energy-intensive than classical diffusion.

Abstract

Bonding between polymeric interfaces is encountered widely in several industrial applications. Many of these bonding processes rely on time-consuming and temperature-dependent classical mechanism of polymer interdiffusion via reptation in a melt state. Here, for the first time, we report a new mechanistic pathway for achieving solid-state polymer bonding by triggering rapid macromolecular acceleration through mechanical deformation. Large-scale molecular simulations reveal that active plastic deformation in glassy polymers, at temperatures well-below the bulk (and surface) glass transition temperatures, is sufficient to cause segmental translations of the polymer chains that lead to interfacial interpenetrations, and formation of new entanglements. The underlying mechanistic basis for this new type of bonding is identified as enhanced molecular-scale dilatations (or densifications) in conjunction with accelerated molecular mobility during plastic deformation. The reported mechanistic insights open promising avenues for designing new bonding technologies or material systems, and transformation of the existing ones to achieve quick and energetically less intensive bonding.