Kraft (Nano)Lignin as Reactive Additive in Epoxy Polymer Bio-Composites.

The demand for high-performance bio-based materials towards achieving more sustainable manufacturing and circular economy models is growing significantly. Kraft lignin (KL) is an abundant and highly functional aromatic/phenolic biopolymer, being the main side product of the pulp and paper industry, as well as of the more recent 2nd generation biorefineries. In this study, KL was incorporated into a glassy epoxy system based on the diglycidyl ether of bisphenol A (DGEBA) and an amine curing agent (Jeffamine D-230), being utilized as partial replacement of the curing agent and the DGEBA prepolymer or as a reactive additive.

Sub-Micro Organosolv Lignin as Bio-Based Epoxy Polymer Component: A Sustainable Curing Agent and Additive.

Sub-micro organosolv lignin (OBs) isolated from beechwood biomass, comprising of sub-micro sized particles (570 nm) with low molecular weight and dispersity and relatively high total phenolic -OH content, is utilized for the production of bio-based epoxy polymer composites. OBs lignin is incorporated into the glassy epoxy system based on diglycidyl ether of bisphenol A (DGEBA) and aliphatic polyoxypropylene α,ω-diamine (Jeffamine D-230), being utilized both as a curing agent, partially replacing D-230, and as an additive, substituting part of both petroleum-derived components. Up to 12 wt % replacement of D-230 by OBs lignin is achieved, whereas approximately 17 wt % of OBs effectively replaces the conventional epoxy polymer.

Synthesis and Characterization of Poly(lactic acid) Composites with Organosolv Lignin.

Lignin, being one of the main structural components of lignocellulosic biomass, is considered the most abundant natural source of phenolics and aromatics. Efforts for its valorisation were recently explored as it is mostly treated as waste from heat/energy production via combustion. Among them, polymer-based lignin composites are a promising approach to both valorise lignin and to fine tune the properties of polymers.