The manufacture of flexible sheets: a novel recycling perspective

Recycling paper sludge waste (PSW) into inexpensive sheets for applications in household interiors, construction, and footwear is a sustainable approach to resource utilisation and pollution reduction. A flexible recycled sheet (FRS) in board form was developed using cellulosic-based PSW from the paper industry and a styrene-butadiene rubber (SBR) binder. Various SBR concentrations were tested to determine the optimal amount for superior mechanical properties. The produced FRS was characterised using Fourier transform infrared spectroscopy, thermogravimetric analysis, high-resolution scanning electron microscopy, and energy-dispersive X-ray spectroscopy. FRS made with 1000 g of PSW:300 ml of SBR exhibited enhanced mechanical properties, including tensile strength (62.32 ± 0.51 MPa), elongation at break (51.99 ± 0.94%), tearing strength (17.76 ± 0.45 N/mm), and flexibility (6.98 ± 0.24%). A biodegradation study, conducted per ASTM D 5988-03, assessed environmental impact by measuring carbon-to-CO₂ conversion in soil over 90 days. All FRS samples showed similar degradation within the first 30 days, with FRS 5 degrading significantly faster thereafter due to its higher cellulose and hemicellulose content. This highlights the potential of PSW-based FRS as an environmentally friendly and mechanically robust material for diverse applications.