Recycled polyolefin-based plastic wastes for sound absorption

Recycling of high-volume polyolefin-based packaging wastes in India is challenging, as they have low recycle value, high levels of contamination, and lack of direct processing methods. This work discusses a two-stage mechanical processing method for recycling the polyolefin-based plastic wastes that are not conventionally recycled. With the objective of improving specific properties like sound absorption and noise reduction, inhomogeneities were introduced in the recycled product. This was achieved by mixing polyolefin-based packaging wastes with other waste materials such as plastic-coated aluminium foils, expanded polystyrene, and coir pith in varying quantities. More than 30 times volume reduction was achieved by a two-stage compression molding process. The sound absorption properties of the recycled materials are found to be comparable to expanded polystyrene and glass wool when small quantities (2-3 wt%) of materials like expanded polystyrene waste and coir pith were added. Impact strength of the recycled material decreased with increasing amounts of secondary additives like metal foils. Flexural strength of the recycled material was found to be maximum at about 30 wt% of metal foils. The end product could find applications in the construction industry due to the sound-absorption properties and the mechanical strength. Copyright © Taylor & Francis Group, LLC.