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

ABSTRACT 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.