Synthesis and Properties of Polyacrylate Pressure-Sensitive Adhesives With Macro-Crosslinkers

To achieve a balance of low modulus, high recovery, and strong adhesion in pressure-sensitive adhesives (PSAs) of flexible displays, a series of crosslinkable oligomers with varied structures and molecular weights are synthesized and subsequently incorporated into acrylate copolymers as macro-crosslinkers. The structure of the macro-crosslinkers is characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance spectroscopy ( 1 H NMR), and gel permeation chromatography (GPC). The effects of the macro-crosslinkers' structure and molecular weight on the properties of copolymers are systematically investigated by differential scanning calorimetry (DSC), rheometer, and universal testing machine. The macro-crosslinkers enhance the chain mobility while maintaining the integrity of the crosslinking network, leading to a more flexible network with a combination of strong cohesion and high chain mobility. Compared to HDDA-crosslinked copolymers, the copolymers with macro-crosslinkers exhibit a lower modulus, superior elongation, and enhanced stress relaxation, while maintaining comparable strain recovery and cyclic stability. For instance, P- cPPG1k exhibits a 26% reduction in modulus, a 60% increase in elongation at break compared to P- HDDA , with an elastic recovery rate maintained over 92% at 200% strain. Moreover, P- cPPG1k exhibits adhesive performance superior to commercial flexible display PSAs, underscoring the practical potential of this strategy.