Research on the manufacture and environmental assessment of vibration and structure-borne sound insulation foams from packaging film waste

Abstract

This study investigates the manufacture and environmental assessment of acoustic insulation foams made from recycled polyethylene (RM) from packaging film waste. Blends of RM with virgin polyethylene (PE) and ethylene-vinyl acetate (EVA) were used to produce cellular structures through chemical (Ch) and physical (Ph) foaming processes. The aim was to develop materials with properties comparable to commercial acoustic insulation products in construction sector, assessing structural integrity and acoustic performance via dynamic stiffness. Products with performance like the commercial were achieved with recycled content ranging from 40 to 80 wt%. These successful cases were also evaluated for environmental impact. The life cycle assessment considered two approaches: one analysing the production of 1 kg of foam (standardized density values), where physical foaming showed a lower environmental footprint, and the other evaluating the mass needed to achieve the dynamic stiffness of the commercial reference (empirical density values), which favoured chemical foaming for producing foams with comparable properties but lower densities. Although physical foaming has environ- mental advantages, the higher densities achieved with RM limit its viability. Consequently, chemical foaming is more environmentally favourable due to lower material consumption. Therefore, Ch_RM:EVA,80:20 is optimal for technical requirements, while Ch_RM:PE,40:60 is more environmentally advantageous. The compromise solution that addresses both technical and environmental aspects is Ch_RM:EVA,40:60. This foam showed acoustic performance equivalent to the commercial, achieved through a manufacturing process and recycled content minimizing environmental impacts. Furthermore, transforming packaging waste into a long-lasting product also reduces waste accumulation and delays non-sustainable but necessary processes like energy generation.