Yan Zhang

Transparent and flexural epoxy resin represents an emerging class of materials for advanced encapsulation and adhesives in the electronics and semiconductor industries. Although toughening components have been reported to improve EP flexibility, multi‐stage curing processes for complete crosslinking require optimization, and EP films' comprehensive properties (flexibility, optical transparency, water barrier, and electrical insulation) have rarely been systematically co‐evaluated. To address these challenges, a novel class of transparent and flexible epoxy films was developed through a fast curing process (80°C/20 min) using m‐xylylenediamine (M‐XDA) as the curing agent. By strategically modulating the molecular ratio of hydrogenated bisphenol A epoxy resin (HBPA) and ethylene glycol diglycidyl ether (EGDE), the optimal balance of multifunctional properties, including exceptional optical transparency, mechanical flexibility, electrical insulation, and barrier performance was achieved. Among the synthesized variants, H3:E7 epoxy demonstrates outstanding characteristics: excellent transparency (transmittance of 90.6%), remarkable flexibility (> 100,000 bending cycles), low water vapor transmission rate (4.1 g·m ⁻² ·24 h ⁻¹ ), superior insulation (1.4 × 10 ¹⁴ Ω·cm) and high adhesive strength (13.4 MPa). Isothermal curing kinetics analysis confirms the scientific validity of the optimized 80°C/20 min rapid‐curing protocol. This work establishes a facile yet effective methodology to expand the application scope of epoxy resins in high‐value technological domains.

Polylactide (PLA), as a prominent bio‐based polymer, has garnered significant interest. However, its high flammability and inherent brittleness hinder broader applications. While bio‐based flame‐retardant systems have been developed to preserve PLA's environmental compatibility, the associated degradation of mechanical performance remains a critical limitation. This study addresses these challenges by engineering a bio‐based flame‐retardant hybrid composed of DL (synthesized from lysine and diethylenetriamine penta‐methylenephosphonic acid via aqueous‐phase chemistry) and graphene oxide (GO). To enhance dispersion within the PLA matrix, GO was surface‐functionalized with polyethylene glycol (PEG). The resulting PLA composite exhibits synergistic enhancements in flame retardancy, mechanical robustness, and UV shielding. PLA/4PEG‐0.08GO/6DL achieves the UL‐94 V‐0 rating, the LOI value of 29.7%. Moreover, the impact strength was improved by 27.5% compared with pure PLA, and Young's modulus is increased from 3401 to 3630 MPa. In addition, the significantly improved UPF value and hydrolytic degradation behavior indicated its good anti‐UV property and environmental friendliness. These results demonstrate the hybrid system's potential to balance sustainability, safety, and performance for advanced PLA applications.

Because of widespread public concern about plastic waste treatment and recycling, there is a global trend toward replacing non-biodegradable polymers with biodegradable polymers. However, the inherent flammability of most biodegradable polymers presents a significant barrier to their potential application, necessitating the rapid development of fire-retardant biodegradable polymers. Herein, three major categories of fire retardants (FRs), including intrinsic FRs, additive FRs, and fire-retardant coatings, especially widely studied additive FRs in the categories of organic, inorganic, and inorganic–organic, are reviewed, revealing how the physical and chemical structures of FRs affect the fire-retardant efficiency of biodegradable polymers and concluding the influencing factors of their fire retardance from the perspective of the physical and chemical structures of FRs. This work provides fundamental data and mechanistic analyses for the fire-retardant parameters of biodegradable polymers by integrating/adding diverse types of FRs, to provide guidance for fabricating highly efficient fire-retardant biodegradable polymer materials and inspiring the development of future research and application of functional biodegradable polymers toward circular economy and greater sustainability.