Akademik Veri Yönetim Sistemi
Composites Part B: Engineering, cilt.323, 2026 (SCI-Expanded, Scopus)
Cellulose-based waste paper fibers have significant potential for the development of sustainable geopolymer composites, but their high water absorption capacity and weak fiber-matrix interface bonding can negatively affect mechanical and durability performance. In this study, to reduce these limitations, the surfaces of waste paper fibers were modified using a polyurethane coating method, and the effects of these fibers on the physical, mechanical, durability, thermal, and acoustic performance of GBFS-based geopolymer composites were experimentally investigated. In this context, coated and uncoated fibers were included in geopolymer mixtures at 1% and 2% volume ratios, and the compressive strength, flexural strength, water absorption behavior, capillary water absorption coefficient, freeze-thaw resistance, sulfate resistance, thermal conductivity, and sound absorption coefficient performances of the samples were comparatively examined. The results showed that the hydrophilic structure of uncoated fibers increased void formation within the matrix, reducing mechanical and durability performance, while the polyurethane coating improved bonding performance by making the fiber-matrix interface hydrophobic. Specifically, it was determined that the mixture containing 2% polyurethane-coated fibers maintained a compressive strength of 34,32 MPa after 60 freeze-thaw cycles and reduced its thermal conductivity coefficient to 0,0801 W/(m.K). SEM–EDS analyses showed that polyurethane-coated paper fibers formed a more homogeneous and chemically more stable Si–Al–Na geopolymer gel network, while unpcoated fibers caused surface heterogeneity and microstructural weakening. The findings show that polyurethane-coated waste paper fibers simultaneously increase mechanical, durability, and functional performance in geopolymer composites through interface engineering.