English Abstract

Chemical Imaging of Resin Adhesive Interface using Soft X-ray Microscopy

Hiroyuki YAMANE *2
Masaki OURA *1
Takaki HATSUI1 *1
*1:RIKEN SPring-8 Center, Sayo, Hyogo , Japan
*2:RIKEN SPring-8 Center, Sayo, Hyogo , Japan. Present address: Photon Science Innovation Center, Aramaki-Aoba, Sendai, Japan
Nippon Gomu Kyokaishi,(2022),95(12),340-346 General Review in Japanese

Adhesive bonding is an interfacial phenomenon that is critical for assembling polymer-matrix composite materials, enabling them to maintain their lightweight and high-stiffness properties. However, the lack of understanding of the adhesion mechanisms at the molecular level has limited the reliability of adhesive bonding for industrial uses. In this article, using soft X-ray microscopy, we demonstrate the visualization of one of the important factors of adhesion; that is, physical and chemical states at the adhesive interface. For this purpose, we prepared a model adhesive interface composed of a thermosetting epoxy resin adhered to a plasma-pretreated thermoplastic resin. We succeeded in observing multiscale phenomena in the adhesion mechanisms, including sub-mm complex interface structure, sub-m distribution of the functional groups, and molecular-level covalent-bond formation. These results provide a benchmark for further research to examine how physical and chemical states correlate with adhesion, and demonstrate that soft X-ray imaging is a promising approach for visualizing the physical and chemical states at adhesive interfaces from the sub-mm level to the molecular level.

Keywords: Adhesive Interface, Chemical Imaging, Soft X-ray Microscopy, Near-edge X-ray Absorption Fine Structure Spectroscopy, Polymer-matrix Structural Composites