An Ultra-Strength, Low-Temperature-Curing Adhesive Enabled by a Polyphenol-Enhanced Phase-Separation Network

Area of Science:

• Materials Science
• Green Chemistry
• Polymer Science

Background:

• Formaldehyde-based adhesives pose environmental and health risks due to volatile emissions.
• Traditional thermosetting adhesive curing requires high energy consumption.
• Developing sustainable and high-performance adhesives is crucial for green manufacturing.

Purpose of the Study:

• To develop an environmentally friendly, water-based adhesive inspired by natural liquid-liquid phase separation.
• To achieve low-temperature rapid curing, reducing energy consumption and eliminating high-temperature processes.
• To create a versatile adhesive with high performance for various substrates and applications.

Main Methods:

• Formulation of a synergistic combination of silicone-acrylic (SA) emulsion, cationic polyamidoamine-epichlorohydrin (PAE), and tannic acid (TA).
• Construction of a phase-separated cross-linked network via multiple dynamic interactions.
• Evaluation of adhesive performance through shear strength tests (cold-pressed plywood, wood, metals), durability tests (boiling), and film property analysis (toughness, tensile strength).

Main Results:

• The bioinspired adhesive demonstrated a wet shear strength of 2.58 MPa for plywood, retaining 1.24 MPa after 72h boiling.
• Achieved bond strengths of 23.5 MPa for wood and 12.95 MPa for metals.
• Processed into self-supporting films with high toughness (>350% elongation) and strength (>16.5 MPa tensile strength).

Conclusions:

• The developed water-based adhesive offers a high-performance, low-environmental-impact alternative to traditional adhesives.
• The bioinspired phase separation strategy enables efficient, low-temperature curing.
• This approach is promising for sustainable composite manufacturing and clean production processes.