2024

Rämö, Virpi; Raipale, Noora; Hiipakka, Marita; Kamppuri, Taina; Paunonen, Sara; Tehrani-Bagha, Ali

<p>Composting offers a potential sustainable end-of-life pathway for nonwoven products that may aerobically disintegrate and eventually biodegrade. Enhancing the biodegradation of nonwovens typically involves incorporating biobased biodegradable fibres. This study explores how nonwoven web formation and consolidation impact aerobic disintegration in composting. Laboratory-scale air-laid, foam-laid and carded sheets (40, 60, and 100 g/m²) with 80 wt% viscose and 20 wt% polylactic acid (PLA) fibres were prepared and thermally bonded. The sheets were characterised by physical and tensile properties, air permeability, water absorption, surface morphology, pore structure and aerobic disintegration in synthetic biowaste media. The nonwoven web formation process affected sheet density and air permeability, while tensile strength and elongation showed dependency on fibre length and orientation. Over 62 days, carded nonwovens showed the highest degree of aerobic disintegration (81%–88%) followed by foam-laid (64%) and air-laid (47%) nonwovens. Scanning electron microscopy (SEM) and X-ray tomography revealed less effective bonding within the carded sheets with 38 mm mono-component PLA fibres compared to the air-laid and foam-laid sheets containing 6 mm bi-component PLA fibres. Denser thermally bonded fibre clusters in air-laid and foam-laid sheets reduced degree of aerobic disintegration. These findings highlight the significance of fibre length, bonding and sheet homogeneity in aerobic disintegration, emphasising the importance of nonwoven web formation and consolidation processes.</p>