Tailoring Ultra-Thin Zif-8-Reinforced Polyvinyl Alcohol Composite Aerogels Fabricated Via Vacuum Freeze-Drying for Sound Absorption Publisher



Khosravipour M ; Golbabaei F ; Alimohammadi I ; Esmaeelpour M R M
Source: Vacuum Published:2026

Abstract

Metal–organic frameworks (MOFs) represent highly promising candidates for the development of advanced sound-absorbing materials. In this study, novel zeolitic imidazolate framework-8 (ZIF-8)/polyvinyl alcohol (PVA) composite aerogels (P5Z1, P5Z2, and P5Z3) were fabricated at a thin thickness of 0.75 cm via an ice-templated freeze-casting approach, which combined freeze-thaw cross-linking and vacuum freeze-drying. Incorporating ZIF-8 successfully reduced the bulk density from 71.92 kg/m3 (pure PVA) to a range of 52.70-61.36 kg/m3 while expanding the physical porosity up to 95.61%. The microstructural variations and experimental sound absorption coefficients (SACs) were systematically evaluated across a broad frequency spectrum 80-6300 Hz using Sound Absorption Average (SAA) and Noise Reduction Coefficient (NRC) indices. The optimized P5Z2 aerogel established the most favorable structural balance (density: 61.36 kg/m3, porosity: 94.89%), yielding an NRC of 0.32 and an SAA of 0.29. This study indicates that the incorporation of ZIF-8 improved mid-frequency acoustic performance through optimized pore architecture. © 2026 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.