Lignin-based thermoplastic biocomposites: from batch system toward continuous compounding

Abstract

The increasing concerns about depletion of petroleum-based resources and environmental issues are highlighting the need to develop materials based on renewable natural resources. In this process, lignin can represent an important role, being a by-product of the forest industry and an alternative renewable raw source for bio-based polymers. As Sweden represents the world's 3rd largest exporter of pulp and paper, many tons of lignin are generated but the majority is disposed of as low-cost biofuel. An attractive alternative is the developing of value-added products such as thermoplastic materials. In this contest, the Swedish company RenCom is contributing to the research for sustainable and renewable thermoplastic lignin. The aim of this Master Thesis is to develop, melt process and analyse sustainable biocomposites materials produced by compounding lignin-based products (Renol® by RenCom) with biodegradable thermoplastic polymers. Their final structural, mechanical and thermal properties are studied to identify suitable matrices and processing parameters for successful preparation of lignin-based biocomposites. The results reveal that the incorporation of Renol® in biocomposites is beneficial for the thermal and the mechanical properties, in the case of more flexible matrices. In this work, the feasibility to transfer the preparation of the biocomposites to continuous process has been assessed, indicating a scalable and green route for successful incorporation of lignin in thermoplastic materials. Moreover, the biocomposites prepared have shown properties suitable for their use in large scale applications, such as packaging and single-use plastics.