Structural Adhesives Tapes Based on a Solid Epoxy Resin and Multifunctional Acrylic Telomers

Area of Science:

• Materials Science
• Polymer Chemistry
• Adhesives Technology

Background:

• Thermally curable pressure-sensitive structural adhesive tapes (SATs) are crucial for demanding applications.
• Optimizing the formulation of SATs is essential for enhancing their performance, particularly adhesion, cohesion, and environmental resistance.

Purpose of the Study:

• To synthesize and characterize multifunctional acrylic telomer solutions (MATs) using different telogens (CBr4 and CBrCl3).
• To investigate the impact of MATs on the properties of thermally curable SATs, including self-adhesive features, curing behavior, and shear strength.
• To evaluate the environmental resistance of the cured adhesive joints.

Main Methods:

• MATs were prepared via thermally initiated telomerization in an epoxy diluent with CBr4 or CBrCl3 as telogens.
• Dynamic viscosity, K-value, and volatile matter content of MATs were analyzed.
• Adhesion, tack, cohesion, and overlap shear strength of SATs were measured.
• Environmental resistance to fuel, humidity, and temperature was assessed.

Main Results:

• Increasing telogen content in MATs significantly improved adhesion, tack, and cohesion of SATs.
• MATs, especially with high telogen content, enhanced the resistance of cured joints to aviation fuel, humidity, and elevated temperatures.
• Optimal overlap shear strength was achieved with SATs using MATs containing 7.5 wt.% CBr4 (16.7 MPa) or 10 wt.% CBrCl3 (15.3 MPa).

Conclusions:

• Multifunctional acrylic telomer solutions are effective in formulating high-performance thermally curable structural adhesive tapes.
• Telogen type and content critically influence the adhesive properties and environmental durability of SATs.
• The developed SATs demonstrate excellent potential for applications requiring robust adhesion and resistance to harsh conditions.