Lignins are the most important aromatic renewable natural resource today, serving as a sustainable, environmentally acceptable alternative feedstock to fossil‐derived chemicals and polymers in a vast scope of value‐added applications. Lignin is a biopolymeric molecule that, together with cellulose, is a fundamental component of higher vascular plants structural cell walls. It can be extracted from by‐products of the pulp and paper industries, agricultural waste and residues, and biorefinery products. Lignin properties may vary depending on source and extraction method with carbon and aromatic as the main compositions in lignin structure. These rich compositions make lignin more valuable, allowing for the creation of high‐value‐added green composites. However, the complex structure of lignin creates low reactivity to interact with crosslinker, and hence chemical modification is substantial to overcome this problem. This review aimed to present and discuss lignin structure, variation of lignin chemical properties regarding its source and extraction process, recent advances in chemical modification of lignin to enhance its reactivity, and potential applications of modified lignin for manufacturing value‐added biocomposites with enhanced properties and lower environmental impact, such as food handling/packaging, seed coating, automotive devices, 3D printing, rubber industry, and wood adhesives.

After cellulose, lignin is the most commonly used natural polymer in green biomaterials. Pulp and paper mills and emerging cellulosic biorefineries are the main sources of technical lignin. However, only 2–5% of lignin has been converted into biomaterials. Making lignin-based polymer biocomposites to replace petroleum-based composites has piqued the interest of many researchers worldwide due to the positive environmental impact of traditional composites over time. In composite development, lignin is being used as a filler in commercial polymers to improve biodegradability and possibly lower production costs. As a natural polymer, lignin may have different properties depending on the isolation method and source, affecting polymer-based composites. The application has been affected by the characteristics of lignin and the uniform distribution of lignin in polymers. The review’s goal was to provide an overview of technical lignin extraction, properties, and its potential appropriate utilization. It was also planned to revisit the lignin-based composites’ preparation procedure as well as their composite characteristics. Solvent casting and extrusion methods are used to fabricate lignin from polymeric matrices such as polypropylene, epoxy, polyvinyl alcohol, polylactic acid, starch, wood fiber, natural rubber, and chitosan. Packaging, biomedical materials, automotive, advanced biocomposites, flame retardant, and other applications for lignin-based composites has existed. As a result, the technology is still being refined to increase the performance of lignin-based biocomposites in several applications. This review could assist explain lignin’s position as a composite additive, which could lead to more efficient processing and application strategies.

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The effects of lignin on mechanical, biodegradability, morphology, and thermal properties of PP/PLA/lignin were investigated. PP/PLA/lignin film were manufactured by adding PP, PLA, lignin and compatibilizer into rheomix at 200°C, at 70 rev min −1 for 30 minthen pressed using Hydraulic Hot Press at 200°C-210°C, at 6 bar for 20 min. The functional groups of PP/ PLA/lignin were analyzed using FTIR. The surface morphology, mechanical properties and thermal stability was measured by SEM, tensile strenght and TGA respectively. TThe FTIR intensity of vibration peak of -CH 3 cm -1 from PP/lignin and PP/PLA/lignin at 997-993, 1458-1451 and 2966-2904 cm -1 was lower than neat PP. The addition of lignin into PP/lignin, PLA/ lignin and PP/PLA/lignin can reduce tensile strength and elongation at break. The thermal stability PP/PLA/lignin was lower than the PP/lignin but higher compared to PP/PLA biocomposites. The biodegradability of PP/PLA/lignin biocomposites was two times higher than that of PP/lignin.

Short Phe-rich oligopeptides, consisting of only four and five amino acids, worked as effective supramolecular hydrogelators for buffer solutions at low gelator concentrations (0.5-1.5 wt %). Among 10 different oligopeptides synthesized, peptide P1 (Ac-Phe-Phe-Phe-Gly-Lys) showed high gelation ability. Transmission electron microscopy observations suggested that the peptide molecules self-assembled into nanofibrous networks, which turned into gels. The hydrogel of peptide P1 showed reversible thermal gel-sol transition and viscoelastic properties typical of a gel. Circular dichroism spectra revealed that peptide P1 formed a β-sheetlike structure, which decreased with increasing temperature. The self-assembly of peptide P1 occurred even in the presence of nutrients in culture media and common surfactants. Escherichia coli and yeast successfully grew on the hydrogel. The hydrogel exhibited low cytotoxicity to animal cells. Finally, we demonstrated that functional compounds can be released from the hydrogel in different manners based on the interaction between the compounds and the hydrogel.

The aim of this research work was to evaluate the potential of using renewable natural feedstock, i.e., Jatropha curcas oil (JCO) for the synthesis of non-isocyanate polyurethane (NIPU) resin for wood composite applications. Commercial polyurethane (PU) is synthesized through a polycondensation reaction between isocyanate and polyol. However, utilizing toxic and unsustainable isocyanates for obtaining PU could contribute to negative impacts on the environment and human health. Therefore, the development of PU from eco-friendly and sustainable resources without the isocyanate route is required. In this work, tetra-n-butyl ammonium bromide was used as the activator to open the epoxy ring with 3-Aminopropyltriethoxisylane as a catalyst to yield urethane of JCO (UJCO). The UJCO were characterized by Fourier Transform Infra-Red spectroscopy (FTIR) and their oxirane, and hydroxyl values were measured. The result showed that a decrease in oxirane value was found while the hydroxyl value was increased during the time, confirming that the urethane group was formed. The presence of functional groups in FTIR spectra at wave numbers 1732.08, 1562.34, and 3348.42 cm −1 indicates the functional groups of C = O (urethane carbonyl), -NH, and -OH, respectively confirmed this finding. The potential applications of NIPU in the wood composite were also outlined.

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The significant progress of supramolecular chemistry since the end of last century includes the development of supramolecular gels. In particular, spatiotemporal self-assembly of synthetic small gelator molecules have attracted increased attention owing to their ability to realize functional properties at a designated space and designated time. Peptides conjugated with hydrophobic moieties are typical examples of a supramolecular gelator (low-molecular-weight gelator, LMWG), which can be designed or programmed to self-assemble to form nanofibers/nanosheets in response to a broad range of stimuli or to microenvironments. In the last decade, several groups reported that the selfassembly of small gelator molecules was achieved inside living cells or on the surfaces of living cells and induced the selective cell death, which would lead to a novel therapeutic approach or a novel cell-selection tool. This focus review outlines the self-assembly of the small gelator molecules inside or around living cells, which controls the cell fates.