Institute of Chemical Industry of Forest Products

The development of sustainable renewable polymers from natural resources has increasingly gained attention from scientists, engineers as well as the general public and government agencies. This review covers recent progress in the field of renewable bio-based monomers and polymers from natural resources: terpenes, terpenoids, and rosin, which are a class of hydrocarbon-rich biomass with abundance and low cost, holding much potential for utilization as organic feedstocks for green plastics and composites. This review details polymerization and copolymerization of terpenes such as pinene, limonene, and myrcene and their derivatives, terpenoids including carvone and menthol, and rosin-derived monomers. The future direction on the utilization of these natural resources is discussed.

Stimuli-responsive bio-based polymeric systems are gaining considerable attention as intelligent versatile tools that show great potential in various fields. In this review, an overview is given of recent developments of stimuli-responsive bio-based polymeric systems. The characteristics of bio-based polymers in different applications are discussed and the superiority of these advanced stimuli-responsive bio-based polymeric systems is highlighted. Furthermore, several emerging applications of these systems including intelligent drug delivery, responsive food packaging and smart water treatment are discussed and the section of intelligent drug delivery is emphasized in detail. Finally, the respective prospects and limitations inherent to these systems are addressed.

Cellulose has attracted considerable attention as the strongest potential candidate feedstock for bio-based polymeric material production. During the past decade, significant progress in the production of biopolymers based on different cellulosic forms has been achieved. This review highlights the most recent advances and developments in the three main routes for the production of cellulose-based biopolymers, and discusses their scope and applications. The use of cellulose fibers, nanocellulose, and cellulose derivatives as fillers or matrices in biocomposite materials is an efficient biosustainable alternative for the production of high-quality polymer composites and functional polymeric materials. The use of cellulose-derived monomers (glucose and other platform chemicals) in the synthesis of sustainable biopolymers and functional polymeric materials not only provides viable replacements for most petroleum-based polymers but also enables the development of novel polymers and functional polymeric materials. The present review describes the current status of biopolymers based on various forms of cellulose and the scope of their importance and applications. Challenges, promising research trends, and methods for dealing with challenges in exploitation of the promising properties of different forms of cellulose, which are vital for the future of the global polymeric industry, are discussed. Sustainable cellulosic biopolymers have potential applications not only in the replacement of existing petroleum-based polymers but also in cellulosic functional polymeric materials for a range of applications from electrochemical and energy-storage devices to biomedical applications.

Bacterial cellulose (BC), with non-toxicity, high purity, and biocompatibility, has been considered as a versatile candidate for various biomedical applications. Recently, the fabrication of BC-based composite scaffolds compounded with other ingredients such as nanoparticles and polymers has received extensive investigation, which enabled the development of numerous promising biomedical products. Additionally, BC-derived nanocrystals (BCNCs) and nanofibrils (BCNFs) have proven to be promising reinforcing agents in a variety of polymeric scaffolds for biomedical applications. In this review, we summarize recent preparation strategies for BC-based and BCNCs- and BCNFs-containing composite scaffolds and their advances in biomedical applications, including wound healing, tissue engineering, and drug delivery, as well as tumor cell culture and cancer treatment. Finally, we present challenges and future perspectives for BC-based composite scaffolds for biomedical applications.

Abstract Ionic conductive hydrogels prepared from naturally abundant cellulose are ideal candidates for constructing flexible electronics from the perspective of commercialization and environmental sustainability. However, cellulosic hydrogels featuring both high mechanical strength and ionic conductivity remain extremely challenging to achieve because the ionic charge carriers tend to destroy the hydrogen-bonding network among cellulose. Here we propose a supramolecular engineering strategy to boost the mechanical performance and ionic conductivity of cellulosic hydrogels by incorporating bentonite (BT) via the strong cellulose-BT coordination interaction and the ion regulation capability of the nanoconfined cellulose-BT intercalated nanostructure. A strong (compressive strength up to 3.2 MPa), tough (fracture energy up to 0.45 MJ m −3 ), yet highly ionic conductive and freezing tolerant (high ionic conductivities of 89.9 and 25.8 mS cm −1 at 25 and −20 °C, respectively) all-natural cellulose-BT hydrogel is successfully realized. These findings open up new perspectives for the design of cellulosic hydrogels and beyond.

Vitrimers are a new type of polymers with promising applications in innovative materials. Epoxidized soybean oil (ESO) is an ideal candidate for vitrimer preparation owing to its abundant epoxy groups. However, preparing plant oil-based vitrimers with high glass transition temperatures (Tg) and strength remains challenging. A novel and fully bio-based vitrimer with a Tg above room temperature was synthesized from ESO and a rosin derivative-fumaropimaric acid (FPA) and exhibited excellent self-healing, shape memory, and reprocessing due to the presence of dynamic covalent bond exchange. The fully bio-based ESO-FPA vitrimer exhibited a Tg of 65 °C and a tensile strength of 16 MPa, which resulted from the rigid structure and tricarboxylic groups of FPA. The effect of transesterification reactions on the network structure was confirmed through stress relaxation. Our work expands the applications of commercial ESO in vitrimer materials and provides a novel approach to prepare bio-based vitrimers with desirable properties.

Abstract Interventions and policies for tackling air pollution issues exist and have been proven to be effective. Membrane materials of nanofibrous morphology are attractive for air filtration, and further alleviate the environmental issues. Electrospinning as a simple and versatile way to fabricate ultrafine fibers has been attracting tremendous attention. Herein, the recent researches and future trends of green electrospinning are expounded from the aspects of green degradable materials, green solution electrospinning, and solvent‐free electrospinning. The green degradable materials, including biomass materials, biosynthetic polymer materials, and chemical synthetic materials are reviewed. Following the concept of green electrospinning, electrospun polymer nanofibers via aqueous solution are discussed; additionally, further trends of solvent‐free electrospinning including melt‐electrospinning, anion‐curing electrospinning, UV‐curing electrospinning, thermo‐curing electrospinning, and supercritical CO 2 ‐assisted electrospinning are highlighted. Furthermore, the applications of these electrospun nanofibrous membranes in the field of air filtration are discussed. In the end, the challenges of green electrospinning and future prospects are summarized. The development of green electrospinning is reviewed with an emphasis on current advanced solvent‐free research, where electrospun nanofibrous membranes are contributing to promising treatment strategies to solve environment issue.

Kaempferol (kae) and its glycosides are widely distributed in nature and show multiple bioactivities, yet few reports have compared them. In this paper, we report the antitumor, antioxidant and anti-inflammatory activity differences of kae, kae-7-O-glucoside (kae-7-O-glu), kae-3-O-rhamnoside (kae-3-O-rha) and kae-3-O-rutinoside (kae-3-O-rut). Kae showed the highest antiproliferation effect on the human hepatoma cell line HepG2, mouse colon cancer cell line CT26 and mouse melanoma cell line B16F1. Kae also significantly inhibited AKT phosphorylation and cleaved caspase-9, caspase-7, caspase-3 and PARP in HepG2 cells. A kae-induced increase in DPPH and ABTS radical scavenging activity, inhibition of concanavalin A (Con A)-induced activation of T cell proliferation and NO or ROS production in LPS-induced RAW 264.7 macrophage cells were also seen. Kae glycosides were used to produce kae via environment-friendly enzymatic hydrolysis. Kae-7-O-glu and kae-3-O-rut were hydrolyzed to kae by β-glucosidase and/or α-L-rhamnosidase. This paper demonstrates the application of enzymatic catalysis to obtain highly biologically active kae. This work provides a novel and efficient preparation of high-value flavone-related products.

Plant biomass is a highly abundant renewable resource that can be converted into several types of high-value-added products, including chemicals, biofuels and advanced materials. In the last few decades, an increasing number of biomass species and processing techniques have been developed to enhance the application of plant biomass followed by the industrial application of some of the products, during which varied technologies have been successfully developed. In this review, we summarize the different sources of plant biomass, the evolving technologies for treating it, and the various products derived from plant biomass. Moreover, the challenges inherent in the valorization of plant biomass used in high-value-added products are also discussed. Overall, with the increased use of plant biomass, the development of treatment technologies, and the solution of the challenges raised during plant biomass valorization, the value-added products derived from plant biomass will become greater in number and more valuable.

Menthane diamine promotes the strength and toughness of H-bonding and disulfide bonding-based self-healing polyurethane elastomers and simultaneously improves the elasticity and self-healing performance.

We synthesized “thermadapt” biomass polymers with shape memory, ultrahigh stretchability or rigidity, remarkable self-healing efficiency, recyclability, and reusable adhesiveness.

, ultrasonic chemical, microwave, and solvothermal) are discussed alongside the synthesis strategies of new COFs and their derivatives. Furthermore, the applications of COFs and their derived materials are demonstrated in air, water, and soil pollution management such as gas capture, catalytic conversion, adsorption, and pollutant removal. Finally, this review highlights the current challenges and prospects for large-scale preparation and application of new COFs and the derived materials. In line with the United Nations Sustainable Development Goals (SDGs) and the needs of digital-enabled technologies (AI and machine learning), this review will encompass the future technical trends for COFs in environmental pollution control.

With rising environmental concerns and depletion of petrochemical resources, biomass-based chemicals have been paid more attention. Polyvinyl chloride (PVC) plasticizers derived from biomass resources (vegetable oil, cardanol, vegetable fatty acid, glycerol and citric acid) have been widely studied to replace petroleum-based o-phthalate plasticizers. These bio-based plasticizers mainly include epoxidized plasticizer, polyester plasticizer, macromolecular plasticizer, flame retardant plasticizer, citric acid ester plasticizer, glyceryl ester plasticizer and internal plasticizer. Bio-based plasticizers with the advantages of renewability, degradability, hypotoxicity, excellent solvent resistant extraction and plasticizing performances make them potential to replace o-phthalate plasticizers partially or totally. In this review, we classify different types of bio-based plasticizers according to their chemical structure and function, and highlight recent advances in multifunctional applications of bio-based plasticizers in PVC products. This study will increase the interest of researchers in bio-based plasticizers and the development of new ideas in this field.

The increasing worldwide oil pollution intensifies the needs for new techniques of separation of oil from oily water.

Abstract Frequent fire disasters have caused massive impacts to the environment, human beings, and the economy. MXene has recently been intensively researched as potential flame retardants to provide passive fire protection for other materials via its physical barrier and catalyzing carbonization effects. In parallel, MXene has also demonstrated a great promise for creating early fire warning sensors, which is an emerging field that has the potential to provide active fire response through its thermoelectric effect. This makes it possible to integrate passive fire retardancy and active fire warning into one MXene‐based fire protection system on demand. However, fulfilling these promises needs more research. Herein, an overview of passive flame‐retardant materials and next‐generation smart fire warning materials/sensors based on MXene and its derivatives is provided. This study reviews their conceptual design, characterization, modification principles, performances, applications, and mechanisms. A discussion of the challenges that need to be solved for their future practical applications and opportunities is also presented.

The design of an environmentally benign cost-effective adsorbent for superfast removal of phosphate from wastewater is vital but remains a huge challenge.

In comparison to the traditional petroleum-based plastics, polylactic acid, the most popular biodegradable plastic, can be decomposed into carbon dioxide and water in the environment. However, the natural degradation of polylactic acid requires a substantial period of time and, more importantly, it is a carbon-emitting process. Therefore, it is highly desirable to develop a novel transformation process that can upcycle the plastic trash into value-added products, especially with high chemical selectivity. Here we demonstrate a one-pot catalytic method to convert polylactic acid into alanine by a simple ammonia solution treatment using a Ru/TiO2 catalyst. The process has a 77% yield of alanine at 140 °C, and an overall selectivity of 94% can be reached by recycling experiments. Importantly, no added hydrogen is used in this process. It has been verified that lactamide and ammonium lactate are the initial intermediates and that the dehydrogenation of ammonium lactate initiates the amination, while Ru nanoparticles are essential for the dehydrogenation/rehydrogenation and amination steps. The process demonstrated here could expand the application of polylactic acid waste and inspire new upcycling strategies for different plastic wastes.

Conductive polymer composites (CPCs) have attracted intensive attention for several decades because they can endow the materials with not only good processability but also various functionalities except the electrical conductivity. It is known that the electrical resistance of the CPCs is dominated by the conductive networks in the polymer matrix. Therefore, tiny change of the conductive networks can lead to remarkable changes in the output electrical signal of the CPCs. Utilizing this stimulus-response behavior of conductive networks to the environment conditions, CPCs can be used to design sensitive sensors to detect or monitor the environment conditions, such as the strain/stress, pressure, temperature, solvent or vapor. This review systematically outlines the preparation, microstructures, properties, and the stimulus-response mechanisms to the environment conditions of the CPCs as well as their applications in various sensitive sensors, including strain sensors, pressure sensors, liquid sensors, vapor sensors, and temperature sensors. Finally, the open question and future challenge of utilizing the stimulus-response behavior of CPCs to design versatile sensors are discussed.

Novel soybean-oil-based (SBO-based) epoxy acrylate (EA) resins were developed via ring-opening reaction of epoxidized soybean oil (ESO) with hydroxyethyl methacrylated maleate (HEMAMA) precursor, a synthesized unsaturated carboxylic acid having two active C═C groups and a side methyl group. Experimental conditions for the synthesis of the precursor and the SBO-based EA (ESO-HEMAMA) product were studied, and their chemical structures were confirmed by FT-IR, 1H NMR, 13C NMR, and gel permeation chromatography. Subsequently, the volatility of HEMAMA was studied and compared with acrylic acid (AA). Furthermore, gel contents and ultimate properties of the UV-cured ESO-HEMAMA resins were investigated and compared with a commercial acrylated ESO (AESO) resin. At last, UV-curing behaviors of the SBO-based EA resins were determined by real-time IR. It was found that the HEMAMA precursor showed much lower volatility than AA, and the optimal pure ESO-HEMAMA resin possessed a C═C functionality up to 6.02 per ESO and biobased content of 65.4%. Meanwhile, the obtained ESO-HEMAMA biomaterials exhibited much superior properties as compared to the AESO resin. For instance, the obtained pure ESO-HEMAMA material possessed a storage modulus at 25 °C of 1.00 GPa, glass transition temperature (Tg) of 70.1 °C, and tensile strength and modulus of 13.4 and 592.1 MPa, which were 9.4, 3.6, 6.9, and 15.7 times the values of the pure AESO material, respectively. The resulting biomaterial with 30% of hydroxyethyl methacrylate diluent even reached a tensile strength of 28.4 MPa and Tg of 89.0 °C. Therefore, the developed SBO-based EA resins are very promising for applications in UV-curable coatings.

Hydrodeoxygenation (HDO) of guaiacol, a typical lignin-derived phenolic compound, at relatively mild conditions was studied over γ-Al2O3 and ZSM-5 supported catalysts with Ni and/or Co as active metal. Among various catalysts, NiCo/γ-Al2O3 catalysts exhibited better guaiacol conversion up to 96.1% with cyclohexanol as the main product in aqueous, due to the proper acidity and interaction between metal particles and support. The effects of process parameters on guaiacol conversion and product distribution were investigated in detail associated with solvent effect. The cleavage of C–O bonds in guaiacol was investigated over NiCo/γ-Al2O3 catalysts in aqueous phase. Phenol was found as the main intermediate with 1-methyl-1,2-cyclohexanediol as another intermediate instead of 2-methoxy-cyclohexanol. The demethoxylation first happened to form phenol, and then, the aromatic ring was hydrogenated to give cyclohexanol after further hydrogenation of cyclohexanone.