New poly(lactic acid)/paper mill sludge bio-composite: preparation and characterization

In recent years, bioplastics are becoming interesting materials as an environmentally sustainable alternative to traditional petrochemical plastics. Poly(lactic acid) (PLA)-based materials play a crucial role in the new generation of bioplastics due to their biodegradability, good performances and suitability for several applications. For this reason, the study of PLA composites is becoming increasingly relevant. At the same time, in this field, an important challenge is the use of waste materials as fillers for polymer composites in order to make them more sustainable. In this context, the papermaking industry produces a large amount of inorganic-rich paper mill sludges which are currently landfilled, causing environmental and economic problems, making important the development of new sustainable strategies for their valorisation. For this reason, the valorisation and reutilization of one of paper mill sludges as a filler/reinforcing agent in PLA composites was evaluated in this research as a green alternative to cellulose and/or other traditional mineral fillers. Positive preliminary tests have shown the massive use of this waste paper mill sludge.