Thermal properties of lignin in copolymers, blends, and composites: a review

The need for renewable alternatives to conventional petroleum based polymers has been the motivation for work on biobased composites, blends and materials whose foundations are carbon neutral feedstocks. Lignin, an abundant plant derived feedstock and waste byproduct of the cellulosic ethanol and pulp and paper industry, qualifies as a renewable material. Despite the fact that it is often difficult to blend lignin with other polymers due to its complex structure and reactivity, published research over the past decades, has focused on issues such as lignin miscibility with other polymers, the thermal and mechanical strength behavior of its copolymers and its fractions as well as efforts at tuning its thermal properties via chemical modifications and other means. As such, this study attempts to offer a comprehensive overview that largely discusses the importance of these processes with the aim of finding an effective, cost efficient and environmentally friendly means that may allow the utilization of this important and largely ignored biopolymer.