Review of Bio‐Fillers Dedicated to Polymer Compositions

ABSTRACT Bio‐fillers are functional substances that are increasingly added to polymer compositions due to their unique properties and sustainable nature. There is a lack of a review publication that comprehensively describes bio‐fillers from different natural origins in various types of polymer, although there are many publications focusing on a narrow range of bio‐filler applications. The aim of this publication is to review the correlation between bio‐fillers and their effect on polymer properties, including mechanical and thermal properties and degradation processes. The scope of the work covers the analysis of cellulose bio‐fillers (nanocellulose, bacterial cellulose, and plant waste raw materials), starch, protein‐based bio‐fillers (of plant and animal origin), and mineral fillers, as well as methods of their modification to improve compatibility with polymers. The work systematizes the current knowledge on different types of bio‐fillers used in polymers and indicates the challenges faced by the use of bio‐fillers.