Miscible Blends of Kraft Lignin Derivatives with Low-T_gPolymers

Abstract

Alkylated and acylated kraft lignins are predominantly composed of well-defined supramacromolecular complexes assembled from thousands of individual components. The integrity of these very high molecular weight species can be compromised as kraft lignin derivatives (which alone are quite brittle) are plasticized when blended with miscible low-T g polymers. The complexes tend to be dismantled when the intermolecular interactions between the lignin components and low-T g polymer molecules are strong; this engenders a counterproductive increase in the proportion of polymeric plasticizer required to reach the plasticization threshold. X-ray powder diffraction analyses of the kraft lignin-based materials reveal two broad distributions of separation distances between the aromatic moieties; these are attributable to relative orientations of rings that are more or less edge-on and cofacially offset. Plasticization broadens the former significantly but has less impact on the latter. A similar effect is observed as the kraft lignin components themselves are reduced in molecular weight to the point where their mere presence enhances the plastic deformation that can be withstood before tensile fracture.

Nucleation ability of advanced functional silica/lignin hybrid fillers in polypropylene composites

“…Moreover, lignin is difficult to process since it cannot be heated to temperature greater than 170°C at which degradation takes place and mechanical properties are dramatically reduced [5]. To overcome these limitations and enhance their potential, different strategies have been realized, e.g., compatibilization of lignin/polymer composites [34,35], production of lignin graft copolymers [36,37], and using the lignin as a monomer for polymerization reactions [38].…”

Glass Transition of Oxygen Plasma Treated Enzymatic Hydrolysis Lignin

“…The T g values are found in a wide temperature range depending on plant species, isolation methods, and post treatments (Hatakeyama et al 1982;Glasser and Jain 1993;Jain and Glasser 1993;Hatakeyama and Quinn 1999;Laborie et al 2004;Li and Sarkanen 2005). As shown in Fig.…”

Chemistry of lignin-based materials

“…169,170 Because lignin contains hydroxyl groups, lignin can behave as the polyol in the polyester synthesis, and also lignin hydroxyl groups can be modifi ed to other functionalities such as carboxylic acid, 171,172 acyl groups, 114,172 epoxy groups 173 and terminal hydroxyl groups. 9,10,12,13,15,16,93,[173][174][175][176][177][178][179] Polyesters are popular components to produce lignin polymeric composites. Lignin may be used as a fi ller to reduce production cost, as a reinforcement agent and a biodegradable component.…”

“…93 Polyesters have been used as a plasticizer in lignin-based polymer blends. 178,179 Alipatic polyester, poly(1,4-butylene adipate) was blended with alkylated lignin, which is functionalized lignin by dialkyl sulfate followed by diazomethane, 181,182 to produce ligninpolyester blend. 178 When the ratio of CH 2 (alkylated lignin) and COO (polyester) group is between 2·5 and 3·0, the lignin-polyester blend demonstrated a low T g with good miscibility according 15 and poly(3-hydroxybutyrate-co-hydroxyvalerate).…”