Polymer/lignin blends: Interactions, properties, applications

Abstract

Lignin is a cheap material available in large quantities, thus the interest in its valorization is increasing both in industry and academia. A possible approach towards value added applications is using it as a component in plastics. However, blending lignin with polymers is not straightforward because of the polarity of lignin molecules resulting in strong self-interactions. The structure and properties of lignin depend on the extraction technology used for its production. The structure of lignin is complex and its characterization difficult. Lignin has been added to various polymers in the last few decades and the resulting material was sometimes called blend, while in other cases composite. Based on arguments we show that lignin forms blends, and these are classified and discussed according to the interactions developing in them, since competitive interactions determine the structure and properties of the blends. Usually even strong interactions are not sufficient to result in complete miscibility. As a consequence lignin is often modified chemically or by plasticization to improve its dispersion in plastics, or a compatibilizer is added to increase interfacial adhesion. Lignin can be used also as a reactive component in various resins and polymers.

Development of high bio‐content polypropylene composites with different industrial lignins

“…Sahoo et al and Sailaja and Deepthi obtained similar results, related to the IZOD impact strength of lignin‐based composites. In this present study, ternary mixture with MAPP resulted in plasticizing effect of the maleated composites . According to Sailaja and Deepthi, blends with compatibilizing agents showed higher values of impact resistance than unmodified lignin‐based composites because of the enhanced dispersion of lignin and the better interfacial interaction between polymer matrix and lignin.…”

Palladium-Catalyzed Functionalization of Kraft Lignin: Ether Linkages through the Telomerization Reaction

“…[4] In this context,c hemical functionalization of lignin is required to access materials that can be processed, mixed with other polymeric materials, [5,6] or used as macromonomers. [4] In this context,c hemical functionalization of lignin is required to access materials that can be processed, mixed with other polymeric materials, [5,6] or used as macromonomers.…”

Natural antioxidants as stabilizers for polymers

“…It can be used as filler, as polyol for polyurethane and polyester synthesis, in phenol formaldehyde and phenol epoxy resins and it was blended with polyolefins, vinyl-polymers, but most successfully with various polyesters, just to mention a few areas [150,151]. Because of the presence of phenolic hydroxyl groups in its polyphenol structure, lignin has metal ion chelating [152], radical scavenging and stabilizing effect in polymers.…”