Interfacial and Optical Properties of Plasma‐Modified Optically Transparent Composites With Sandwich‐Structure Based on Waste Textiles

Glass fiber‐reinforced polymer (GFRP) composites are advanced optically transparent materials, with ongoing efforts to enhance their mechanical and optical performance. In this study, glass fiber fabrics were modified via low‐temperature plasma treatment, and sandwich‐structured translucent composites were fabricated using modified glass fiber fabrics, plain‐woven silk fabrics, and recycled curtain fabrics with epoxy resin through vacuum bag pressure molding (VBPM). The effects of plasma power and duration on interfacial properties were examined at both micro and macro levels. Microscopically, the optimal interfacial shear strength reached 18.2 MPa under 175 W for 120 s. Plasma treatment introduced active functional groups (O–H, C = O, C–O–C), reduced surface contact angle by 47.1%, and increased surface roughness to 3.84 nm. Macroscopically, the GF‐175 W‐120 s composites achieved the highest bending strength and modulus at 474.8 MPa and 21.7 GPa, increasing by 9.3% and 14% over untreated samples. Acoustic emission analysis indicated fiber fracture as the dominant failure mode, confirming superior mechanical performance. Optical properties remained largely unaffected by plasma treatment, with variations in transmittance, light intensity, and color rendering index under 1%. Both modified and unmodified composites showed uniform luminance and soft optical characteristics. In conclusion, plasma‐modified GFRP composites exhibited significantly improved mechanical properties while maintaining excellent optical transparency, making them promising candidates for modern architectural decoration.