چكيده لاتين
Pressure-sensitive adhesives (PSAs) have gained a prominent position in advanced industries such as electronics, optoelectronics, optical devices, and packaging due to their ability to provide instant bonding without the need for heat or solvents, ease of application, high flexibility, and capability to adhere to various substrates. Among them, polyacrylate-based adhesives are widely applied owing to their excellent optical transparency, good resistance to ultraviolet (UV) radiation, and favorable rheological properties. However, limitations such as performance deterioration at elevated temperatures, low cohesive strength, and moisture sensitivity reduce their efficiency under demanding operating conditions.In this study, a hybrid system (ECS/WPU) was designed and developed to address these challenges, based on a polyacrylate copolymer synthesized via semi-continuous emulsion polymerization with a core–shell structure and a UV-curable waterborne polyurethane. The acrylate component provides optical transparency, UV resistance, and weather stability, while the polyurethane phase, with alternating hard–soft segments and hydrogen bonding interactions, enhances toughness, flexibility, and internal strength.To further improve the thermal, mechanical, and rheological properties, layered double hydroxide (LDH) nanoparticles modified with phytic acid were incorporated into the system. Surface modification of LDH led to uniform particle dispersion, improved interfacial compatibility, prevention of aggregation, and enhanced hydrogen bonding and electrostatic interactions with the polymer matrix. Moreover, the phosphorus-rich groups of phytic acid contributed to thermal resistance by promoting char formation and the development of protective carbonaceous layers at elevated temperatures. The modification of nanoparticles was confirmed using FTIR, XRD, and TGA analyses. The stability of ECS/WPU dispersions and ECS/WPU formulations containing 1, 3, and 5 wt% phytic acid-modified LDH was verified over one month without signs of coagulation or sedimentation.The prepared nanocomposite samples were UV-cured and evaluated by UV–Vis optical transparency, tack, peel adhesion, shear strength, and TGA analyses. Results showed that the addition of 3 wt% modified LDH provided the most significant simultaneous improvements, including optical transparency (99.9%), tack strength (19 N/25 mm), peel adhesion (47 N/25 mm), and shear strength (57.6 MPa). Furthermore, TGA results indicated a char yield of 36.20% at 600 °C, demonstrating remarkable thermal stability.Overall, the optimized formulation fulfills the essential requirements of advanced PSAs for use in electronics and optoelectronics, including thermal stability, high adhesion under humid conditions, phase uniformity, optical transparency, repeated bending flexibility, and environmental compatibility. This hybrid system can serve as a new generation of PSAs for applications such as flexible display coatings, optical films, and photoelectronic devices.
