Clicking Biobased Polyphenols: A Sustainable Platform for Aromatic Polymeric Materials

Abstract

Lignin, tannins, and cashew nut shell liquid are considered the main sources of aromatic-based macromolecules. They represent an abundant alternative feedstock for the elaboration of aromatic chemicals and polymers, with a view to replacing some fossil-based fractions. Located in different tissues of plants, these compounds, with a large diversity and structural complexity, have, to date, been considered as byproducts derived from fractionation-separation industrial processes with low added value. In the last decade, the use of click chemistry as a tool for the synthesis of controlled macromolecular architectures has seen much development in fundamental and applied research for a wide range of applications. It could represent a valid solution to overcome the main limitations encountered in the chemical modification of natural sources of chemicals, with an environmentally friendly approach to create new substrates for the development of innovative polymers and materials. After a brief description of the main aromatic biopolymers, including the main extraction techniques, along with their structure and their properties, this Review describes chemical modifications that have mainly been focused on natural polyphenols, with the aim of introducing clickable groups, and their further use for the synthesis of biobased materials and additives. Special emphasis is given to several as-yet unexplored chemical features that could contribute to further fundamental and applied materials science research.

Selective Primary Alcohol Oxidation of Lignin Streams from Butanol‐Pretreated Agricultural Waste Biomass

“…With RHBL g-oxCA in hand, we decided to couple the newly introduced carboxylic acids with aniline 10,a sw ef elt this represented af lexible approach to grafting onto the lignin backbone that complemented other recent reports from our group and others. [5,[46][47][48][49][50][51][52] Initially, model 11 was synthesized from 9 and 10 to aid characterization of the final lignin (Scheme 1). RHBL g-oxCA was then coupled with 10 by using EDC, Et 3 Na nd HOBt at RT for 24 h( Lignin general procedure D).…”

Lignin‐Based Polyurethane: Recent Advances and Future Perspectives

“…The coatings also had good electrical conductivity (0.276 S m −1 ). [ 90 ] Meanwhile, introduction of thiols, double bonds, triple bonds, azide groups, furan groups, maleimide groups to lignin for carrying out click chemistry reactions, [ 91 ] and addition of active groups to lignin for controllable living polymerization are commonly used for lignin modification. [ 92 ] Past research polymerized 5‐acrylamide pentane through RAFT to obtain a polymer with an azide end group, and then it reacted with chemically modified lignin with a triple bond to obtain a pendant branch with multiple hydrogen bonding sites.…”

Geopolymer: A Review of Structure, Applications and Properties of Fiber Reinforced Composites

“…It acts as a binding agent between cellulose and lignin [56]. Lignin is an amorphous polymer of complex structure and aromatic nature formed by phenyl propanoid units and is responsible for the mechanical resistance of plants [60].…”