Three-dimensional Cross-linked Network Research Articles

Ratio optimization and grouting effect of low-viscosity and high-flexibility polymer

A new waterborne epoxy resin (polymer) was studied as a potential grouting material to improve the conventional epoxy resin's high viscosity, brittleness and poor environmental performance. The polymer's formulation was meticulously tailored and optimized by adjusting the curing/hardening time, solid content, viscosity and mechanical properties. Concurrently, grouting tests and scanning electron microscope (SEM) were carried out to scrutinize the diffusion effects and microscopic morphology of three distinct grouted sands, employing polymer, superfine cement and sodium silicates as grouting materials. The results show that the polymer performance is optimal when the polymer ratio is CC-190. CC-190 exhibits a homogeneous composition with 100 % solid content. The initial viscosity of CC-190 stands at a mere 19.2 mPa·s and peak compressive strength of 10.8 MPa. The compression ratio (compression height/original height) and rebound rate (rebound height/original height) of CC-190 remain consistently above 35 % and 93 %, respectively. Grouting tests underscore that polymer outperforms superfine cement and sodium silicates in terms of diffusion distance and grouting volume. Microscopic examination of the grouted sands elucidates that the polymer engenders a sophisticated three-dimensional cross-linked skeletal network, effectively binding and encapsulating individual sand particles. This skeletal framework imparts robust binding forces, ensuring the structural integrity of the grouted sand when subjected to external forces.

Mechanism of Inhibiting Spontaneous Coal Combustion by Dopa Hydrosol

ABSTRACT A new type of biomass environmentally friendly hydrosol (DEP) was proposed to inhibit coal spontaneous combustion (CSC). The DEP consists of two parts, the PDopa side chain solution formed by the redox reaction of Dopa and EGCG and the main chain sol solution formed by the free radical polymerization of AA under the action of APS initiator. The −COOH, −NH2, and −OH in Dopa can be grafted onto the skeleton of the main chain via double strong hydrogen bonding interactions with the −COOH group in PAA to form a stable three-dimensional cross-linked network structure. DEP can inhibit CSC through three aspects: oxygen isolation, increasing the activation energy of coal oxidation, scavenging active groups and free radicals. The calculation simulation results show that EGCG in DEP can remove various active free radicals with lower activation energy at room temperature, breaking the chain cycle reaction of coal spontaneous combustion, which proves its high efficiency. This study provides a new way to apply mussel-inspired adhesion mechanisms to the prevention of CSC.

Preparation of chlorinated polyethylene/carbon black/benzoxazine composites with positive temperature coefficient effects

Chlorinated polyethylene (CPE)/carbon black (CB)/ benzoxazine composites with Positive Temperature Coefficient (PTC) characteristics are prepared using the conventional melt-mixing method. The research investigates how benzoxazine content and curing time impact the PTC/NTC characteristics, resistivity, microstructure, and crystallization behavior of these composites.The findings demonstrated a positive correlation between the room temperature resistivity of CPE/CB/benzoxazine composites and benzoxazine content, making the control of benzoxazine content particularly important. Scanning electron microscopy (SEM) reveals that these composites maintain a porous isolated structure regardless of curing time. However, crystallinity decreases as curing time increases. Optimal conditions are achieved with benzoxazine concentration of 2 wt% and a curing time of 45 minutes, resulting in a PTC intensity peak exceeding 5 after R-T cycling. Additionally, at 2 wt% benzoxazine content and a curing time of 60 minutes, a three-dimensional cross-linked network is formed. This network confines carbon black within specific regions, preventing large-scale aggregation and eliminating the NTC effect. After three thermal cycles, the PTC intensity stabilizes around 3.8, indicating good cycling stability.

Developments in Emerging Topical Drug Delivery Systems for Ocular Disorders.

According to the current information, using nano gels in the eyes have therapeutic benefits. Industry growth in the pharmaceutical and healthcare sectors has been filled by nanotechnology. Traditional ocular preparations have a short retention duration and restricted drug bioavailability because of the eye's architectural and physiological barriers, a big issue for physicians, patients, and chemists. In contrast, nano gels can encapsulate drugs within threedimensional cross-linked polymeric networks. Because of their distinctive structural designs and preparation methods, they can deliver loaded medications in a controlled and sustained manner, enhancing patient compliance and therapeutic efficacy. Due to their excellent drugloading capacity and biocompatibility, nano-gels outperform other nano-carriers. This study focuses on using nano gels to treat eye diseases and provides a brief overview of their creation and response to stimuli. Our understanding of topical drug administration will be advanced using nano gel developments to treat common ocular diseases such as glaucoma, cataracts, dry eye syndrome, bacterial keratitis, and linked medication-loaded contact lenses and natural active ingredients.

Prediction and investigation of water repeated absorption and release properties of superabsorbent polymers during the dry-wet cycles in different solutions

Superabsorbent polymers (SAP) with a three-dimensional cross-linked network structure are used in the concrete field due to their good water absorption and water retention properties. The changes of its repeated water absorption and release properties have an important impact on crack healing, but there is still a lack of relevant research. This study mainly uses the tea-bag method to explore the repeated water absorption and release behavior of sodium polyacrylate and polyacrylic acid-acrylamide copolymers in deionized water, cement filtrate, and saturated calcium hydroxide solution. The quantitative analysis of the change in the peak area of the water-absorbing functional group was performed by fourier transform infrared spectroscopy. The morphology and elements of SAP under different dry-wet cycles were analyzed by scanning electron microscope-energy spectrum analysis. The repeated swelling behavior of SAP was predicted using the classical models. The results showed that the repeated water absorption performance of SAP gradually decreased with the increase of the number of wet-dry cycles. The slope of the curve for the second-order equation gradually increases, and the peak area corresponding to the carboxyl functional group also gradually increases. And the rate and amount of water release gradually increase. For sodium polyacrylate, with the increase in the number of wet-dry- cycles, the increase in the content of calcium, magnesium, and aluminum elements is accompanied by a significant decrease in the content of sodium elements. In contrast, the calcium content on the surface of polyacrylic acid-acrylamide copolymer increased, but the sodium content only slightly decreased.

Transparent, robust, and anti-fingerprint silicone coating with a three-dimensional cross-linked network enabled by hydrosilylation reaction

Silicone coatings with anti-smudge, anti-fingerprint, abrasion resistance, and ultraviolet (UV) resistance properties are increasingly demanded for touch screens as the development of artificial intelligence and human-computer interaction interfaces. Herein, a transparent, robust, and self-cleaning silicone coating was developed by incorporating cage-like structures and long carbon chains into a 3D cross-linked network via the rational combination of polymethylhydrosiloxane (PMHS), PSS-Octavinyl substituted (VPOSS), lauryl acrylate (LA), and 1,2-epoxy-4-vinylcyclohexane (EVCH) through hydrosilylation reaction with the presence of Karstedt catalysts. After introducing sealed diphenyliodonium phosphate (I-200), the silicone coating (PVLE-I-200) demonstrated excellent pencil hardness, anti-smudge, and abrasion resistance, and its average transmittance of visible light reached about 92 %. Owing to the low surface energy carbon chains, the coating showed amphiphobic properties and excellent anti-fingerprint property. The binding between cyclohexyl epoxy and glass substrate contributed to the high adhesion of the coating, which remained nearly intact and slightly reduced surface wettability after 500 friction cycles of sandpaper. In addition, the PVLE-I-200 coating demonstrated UV resistance which could withstand 200 h of UV irradiation attributed to the cage-like structure of VPOSS. The functional silicone coating provides insights into the development of environmentally friendly coatings for touch screens with high transparency, abrasion resistance, anti-smudge, and anti-fingerprint properties.

Tracking protein aggregation behavior and molecular interactions induced by conformational alterations in the formation of myofibrillar protein-Abelmoschus manihot gum mixed gels during heating process

The present study aimed to systematically investigate the effects of different Abelmoschus manihot gum (AMG) concentrations (0–0.5%, w/w) on the formation of myofibrillar protein (MP) gels during heating process (30–80 °C) based on conformational alterations, protein aggregation behavior and molecular interactions. With the increase of temperature, the fluorescence intensity and α-helix content significantly decreased, revealing conformational transition of MP molecular. Dynamic rheological results indicated that MP had completely denatured and formed temporary gel at 50 °C, and completely formed irreversible cross-linked three-dimensional network structure at 80 °C. Moreover, the addition of AMG decreased the fluorescence intensity, as well as induced the transition of MP from α-helix to β-sheet during the whole heating process. Furthermore, AMG addition significantly decreased the turbidity and improved solubility of MP (P < 0.05), especially for at 0.3% AMG concentration, indicating that AMG accelerated the early unfolding and aggregation of MP during heating process. This was verified by the dynamic rheological results. Additionally, hydrophobic interactions and disulfide bonds were the main molecular forces to induce the formation of MP-AMG mixed gel. Therefore, our present results provided the new insights into the formation of MP-AMG mixed thermal-induced gel, and also contributed to the practical application of AMG in meat processing.

Liquid-free, tough and transparent ionic conductive elastomers based on nanocellulose for multi-functional sensors and triboelectric nanogenerators

Stretchable and transparent ionic conductors have attracted great interest due to their promising applications in flexible wearable electronics. The obvious drawbacks of gel-based ionic conductors such as hydrogels (e.g., evaporation or freezing of water) have driven the demand for liquid-free ionic conductors. This paper reports a new strategy for fabricating transparent, liquid-free ionic conductive elastomers based on renewable nanocellulose. A three-dimensional cellulose skeleton was constructed through ionic cross-linking, and the physically and chemically cross-linked dual network structure was prepared by in situ polymerization of the polymerizable deep eutectic solvent (PDES) therein. The homogeneous three-dimensional cross-linked network provides a site for energy dissipation and ionic migration. Results show that the elastomers retain good transparency and achieve significantly improved mechanical strength, toughness and ionic conductivity. Therefore, they can be applied as multi-functional sensors and triboelectric nanogenerators (TENG). For the optimized TENG, output voltage, current and charge reach 115 V, 6 μA, and 40 nC, respectively. A maximum output power density of 0.35 W/m2 is achieved, and the collected mechanical energy can light up LEDs and power an electronic clock. In addition, the elastomers maintain reliable performance even at low/high temperatures, enabling use in harsh environments. In conclusion, this study developed a promising strategy for the construction of sustainable liquid-free ionic conductors utilizing natural polysaccharides.

ADVANCEMENTS IN THERAPEUTICS: THE ROLE OF NANOPARTICLE-INFUSED HYDROGELS IN REVOLUTIONIZING DRUG DELIVERY

Nanoparticles loaded hydrogel has emerged as a promising strategy in the field of drug delivery systems, offering unique advantages in terms of controlled release, enhanced bioavailability, and targeted delivery of therapeutic agents. Nanoparticles, typically ranging from 1 to 100 nanometers in size, serve as carriers for drugs, encapsulating them within their matrix and protecting them from degradation. Hydrogels, on the other hand, are three-dimensional cross-linked networks of hydrophilic polymers capable of absorbing and retaining large amounts of water. It aims to provide a comprehensive understanding of nanoparticles loaded hydrogel in drug delivery systems by elucidating the relationship between nanoparticles and hydrogels and their synergistic effects on drug delivery. Firstly, the properties of nanoparticles, including size, surface charge, and composition, significantly influence their interactions with hydrogels and the encapsulation efficiency of drugs. Secondly, the unique characteristics of hydrogels, such as tunable swelling behavior and biocompatibility, complement the stability and sustained release kinetics of nanoparticles.Furthermore, the incorporation of nanoparticles into hydrogel matrices enhances their mechanical strength and allows for the development of stimuli-responsive systems, enabling on-demand drug release triggered by external stimuli such as pH, temperature, or magnetic fields. The synergistic combination of nanoparticles and hydrogels opens up new avenues for the design of advanced drug delivery systems with improved therapeutic efficacy and reduced side effects. In conclusion, nanoparticles loaded hydrogel represents a promising platform for the development of next-generation drug delivery systems, offering unprecedented control over drug release kinetics and targeting capabilities. This review highlights the importance of understanding the interplay between nanoparticles and hydrogels in optimizing the performance of drug delivery systems for various biomedical applications.

Three-dimensional cross-linked network deep eutectic gel polymer electrolyte with the self-healing ability enable by hydrogen bonds and dynamic disulfide bonds

Solid polymer electrolytes (SPEs) are effective solutions for the development of high-performance and flexible lithium metal batteries (LMBs). However, the key problems of SPEs including low ionic conductivity and inability to repair damage have hindered their industrialization process. In this work, a three-dimensional (3D) cross-linked network gel polymer electrolyte (CNGPE) is designed. The addition of deep eutectic solvent (DES) improves the ionic conductivity of CNGPE. The hydrogen bonds and dynamic disulfide bonds in the 3D cross-linked network endow CNGPE rapid self-healing ability at ambient temperature. In addition, the addition of lithium difluoro(oxalato)borate (LiDFOB) and lithium nitrate (LiNO3) helps to form a stable solid electrolyte interface (SEI). Due to the ingenious design, the Li/CNGPE/Li symmetrical cell exhibits excellent interface stability and no short circuit occurs for more than 800 h. The assembled LiFePO4/CNGPE/Li cell exhibits a discharge specific capacity of 126 mAh g−1 after 960 cycles at 0.5C. This work has shown that the self-healing gel polymer electrolyte containing DES provides an effective and feasible method for the development of high-performance LMBs.

Three-Dimensional Cross-Linking Network Coating for the Flame Retardant of Bio-Based Polyamide 56 Fabric by Weak Bonds.

Weak bonds usually make macromolecules stronger; therefore, they are often used to enhance the mechanical strength of polymers. Not enough studies have been reported on the use of weak bonds in flame retardants. A water-soluble polyelectrolyte complex composed of polyethyleneimine (PEI), sodium tripolyphosphate (STPP) and melamine (MEL) was designed and utilized to treat bio-based polyamide 56 (PA56) by a simple three-step process. It was found that weak bonds cross-linked the three compounds to a 3D network structure with MEL on the surface of the coating under mild conditions. The thermal stability and flame retardancy of PA56 fabrics were improved by the controlled coating without losing their mechanical properties. After washing 50 times, PA56 still kept good flame retardancy. The cross-linking network structure of the flame retardant enhanced both the thermal stability and durability of the fabric. STPP acted as a catalyst for the breakage of the PA56 molecular chain, PEI facilitated the char formation and MEL released non-combustible gases. The synergistic effect of all compounds was exploited by using weak bonds. This simple method of developing structures with 3D cross-linking using weak bonds provides a new strategy for the preparation of low-cost and environmentally friendly flame retardants.

Advancements in Noble Metal-Decorated Porous Carbon Nanoarchitectures: Key Catalysts for Direct Liquid Fuel Cells.

Noble-metal nanocrystals have emerged as essential electrode materials for catalytic oxidation of organic small molecule fuels in direct liquid fuel cells (DLFCs). However, for large-scale commercialization of DLFCs, adopting cost-effective techniques and optimizing their structures using advanced matrices are crucial. Notably, noble metal-decorated porous carbon nanoarchitectures exhibit exceptional electrocatalytic performances owing to their three-dimensional cross-linked porous networks, large accessible surface areas, homogeneous dispersion (of noble metals), reliable structural stability, and outstanding electrical conductivity. Consequently, they can be utilized to develop next-generation anode catalysts for DLFCs. Considering the recent expeditious advancements in this field, this comprehensive review provides an overview of the current progress in noble metal-decorated porous carbon nanoarchitectures. This paper meticulously outlines the associated synthetic strategies, precise microstructure regulation techniques, and their application in electrooxidation of small organic molecules. Furthermore, the review highlights the research challenges and future opportunities in this prospective research field, offering valuable insights for both researchers and industry experts.

Geometry-based cross-linking algorithm for modeling resorcinol resins through united-atom molecular dynamics simulations

The addition-condensation polymerization (ACP) of resorcinol with formaldehyde and the electrochemical polymerization (ECP) of resorcinol were desirable to improve the performances of resins. To achieve computational design, a new geometry-based cross-linking modeling algorithm for three-dimensional (3D) cross-linked network structures of resorcinol resins was developed for molecular dynamics (MD) simulations using a united-atom model. The ACP and ECP of resorcinol were successfully modeled using one algorithm by changing the parameters of the reaction rate constants of methylene, ether, and biphenyl bond formations. Furthermore, reaction judgment was performed under a reaction probability function comprising the Gaussian functions based on the interatomic distance of the reaction candidate atom pairs and interior angles regarding the spatial arrangement of two resorcinol rings. This geometry-based cross-linking algorithm successfully generated strainless 3D cross-linked network structures of the ACP and ECP resorcinol resins without the formation of highly bent unstable structures, such as U-shaped biphenyls. The MD simulation results indicated that the cross-linking of the ACP resin comprising methylene linkages proceeded with a network structure formation mechanism similar to that of phenolic resins, where the cross-linked network structure was determined at the gel point and the reactions after the gel point were to fix and freeze the network structure. For the ECP resins comprising ether and biphenyl linkages, the molar ratio of ether to biphenyl bonds affected the elastic property of the resins, and the incorporation of rigid biphenyl structures into ether-linkage networks increased the elastic modulus. Moreover, an increase in rigidity was observed as a decrease in the Poisson's ratio.

Integrating with a tough framework and efficient self-healing behavior based on a flexible polymer skeleton for Si anode binders in lithium-ion cells

As a prospective and efficient strategy to address the volume expansion of the Si nanoparticles, the binder plays an increasingly significant role in the Si anode of lithium-ion batteries. Based on the inspiration of natural physics and cross-linked networks, a functional (named polyacrylic acid-citric acid-polyethyleneimine) binder that is similar to a flexible polymer skeleton integrated with a tough framework and efficient self-healing behavior is designed to achieve long cycling stability for Si anodes. The cross-linked network can be stabilized by the amide bonds, formed by polyethyleneimine (PEI) and polyacrylic acid (PAA). Based on this, citric acid (CA) can be added to form multiple hydrogen bonds, whose carboxyl groups can also establish a more reversible cross-linked network with Si particles. Then, PEI and CA molecules can connect with PAA to form a “rigid and flexible” structure. The expansion stress of Si nanoparticles is relieved by the protective buffer layer built by the addition of PEI and CA molecules. In addition, PAA, PEI, and CA work together to solve the problem that the action of CA and PAA alone cannot perform well under large currents. Hence, this water-based binder with a three-dimensional cross-linked network structure with self-healing ability has better performance during cycling: at a current density of 0.2C, it still has a capacity of 2017.4 mAh·g−1 after 200 cycles, with a capacity retention rate of 80.7 % (1745.3 mAh·g−1, 300 cycles, a capacity retention of 74.9 %).

Properties of wheat gluten based wood adhesives enhanced by transglutaminase and epichlorohydrin

Bio-based eco-friendly products are well-received globally due to increasingly scarce petroleum resources and growing public concern about human health risks and environmental concerns. In this study, wheat gluten (WG) as the raw material modified with transglutaminase (TGase) and epichlorohydrin (ECH) was used to develop an eco-friendly bio-based adhesive. Effects of TGase and ECH on the properties of the adhesive were emphatically discussed. The dry and wet shear strengths of the combined modified adhesive achieved at 3.21 MPa and 0.81 MPa, which was higher than the Chinese National Standard Ⅱ plywood requirements (0.7 MPa). Meanwhile, the solid content and the protein surface hydrophobicity H0 were increased to 28.27 % and 636.54, respectively. These improvements were mainly because, during the modification, the structure of WG became more stretched after ethanol treatment. Then the TGase promoted the cross-linking of the protein molecules and enhanced the cohesion strength of the adhesive system. Finally the ECH further cross-linked and aggregated with exposed active groups to varying degrees, and formed a compact three-dimensional cross-linked network structure, which allowed the WG-based adhesive to form a smoother and more uniform microscopic surface and better water resistance. The obtained adhesives might be utilized to substitute petroleum-derived adhesives in the plywood sector, providing ideas and references for future eco-friendly adhesive research and increasing the high value usage of wheat starch processing by-products.

Tailoring Three-Dimensional Cross-Linked Networks Based on Water-Soluble Polymeric Materials for Stable Silicon Anode.

For stable battery operation of silicon (Si)-based anodes, utilizing cross-linked three-dimensional (3D) network binders has emerged as an effective strategy to mitigate significant volume fluctuations of Si particles. In the design of cross-linked network binders, careful selection of appropriate cross-linking agents is crucial to maintaining a balance between the robustness and functionality of the network. Herein, we strategically design and optimize a 3D cross-linked network binder through a comprehensive analysis of cross-linking agents. The proposed network is composed of poly(vinyl alcohol) grafted poly(acrylic acid) (PVA-g-PAA, PVgA) and aromatic diamines. PVgA is chosen as the polymer backbone owing to its high flexibility and facile synthesis using an ecofriendly water solvent. Subsequently, an aromatic diamine is employed as a cross-linker to construct a robust amide network that features a resonance-stabilized high modulus and enhanced adhesion. Comparative investigations of three cross-linkers, 2,2'-bis(trifluoromethyl)benzidine, 3,3'-oxidianiline, and 4,4'-oxybis[3-(trifluoromethyl)aniline] (TFODA), highlight the roles of the trifluoromethyl group (-CF3) and the ether linkage. Consequently, PVgA cross-linked with TFODA (PVgA-TFODA), featuring both -CF3 and -O-, establishes a well-balanced 3D network characterized by heightened elasticity and improved binding forces. The optimized Si and SiOx/graphite composite electrodes with the PVgA-TFODA binder demonstrate impressive structural stability and stable cycling. This study offers a novel perspective on designing cross-linked network binders, showcasing the benefits of a multidimensional approach considering chemical and physical interactions.

PH dependent biocompatible room temperature covalent organic polymers for selective chemotherapeutic drug delivery

Covalent organic polymers (COP) are a special class of two-dimensional and three-dimensional cross-linked polymeric networks with repeating organic units. They are ideally suited for drug delivery applications because of their large surface area, porous nature, and tunable properties. Furan-2,5-dicarbohydrazide and 1,3,5-triformylbenzene were used to synthesize pH-responsive hydrazone-linked furan-based spherical COP(FRT-COP) at room temperature. The formulated FRT-COP were later stabilized using hyaluronic acid (HA) and then encapsulated anticancer drug doxorubicin (DOX), utilizing the porous structure of the synthesized COP. The newly developed FRT-COP have a pore size of 10 nm, and FRT-COP-DOX-HA exhibit drug loading capacity of 34.4 % and an encapsulation efficiency of 52.32 %. The 80 % viability of NIH 3T3 cells and 82.1 % viability of the CT2A cells, even at a higher concentration of 100 μg/mL of the carrier system, proves the outstanding biocompatibility of the carrier system for chemotherapeutic drug delivery administration. The FRT-COP-DOX-HA-treated NIH-3T3 normal cell line exhibits a viability of 80.59 % at a material concentration of 25 μg/mL. Furthermore, CT2A cancer cell lines show a viability of 33.1 % at a material concentration of 25 μg/mL. The in vivo results obtained from the experiments performed on male BALB/c nude mice also unequivocally demonstrated the exceptional suitability of the proposed drug delivery carrier system for antitumor chemotherapeutic drug administration.

Electronically modified hierarchical porous carbon by N, P heteroatoms for zinc ion hybrid capacitor

Due to the low cost and steady physicochemical properties of carbon materials, zinc-ion hybrid capacitors (ZICs) composed of carbon cathode and Zn anode have aroused considerable attracts in recent years. However, the unsatisfactory capacity and electrochemical kinetics of carbonaceous cathode hinder its application in ZICs. Herein, a facile self-template thermal treatment method was proposed to prepare N, P co-doped hierarchical porous carbons (NP-HPCs). The electronically modified NP-HPC3 has an ultrahigh ratio of active N species and abundant micropores, which is favorable for zinc ions adsorption. In addition, the three-dimensional cross-linked network with abundant mesoporous cavities synchronously boosts electrons/ions transfer kinetics. Ex-situ characterization shows that the introduction of N, P heteroatoms is helpful to improve the adsorption of zinc ions. Thanks to these favorable structural characteristics, the NP-HPC3 displays an exceptional specific capacitance (275.0 F g−1 at 0.1 A g−1) and rate capability (182.0 F g−1 at 20 A g−1). More significantly, the NP-HPC3-based ZIC delivers a prominent energy density of 107.8 Wh kg−1 at a power density of 90.7 W kg−1, a long cycle life (96.9 % capacitance retention after 10,000 cycles) together with an outstanding anti-self-discharge performance (0.001145 V h−1@200 h). This study not only affords a feasible and environmental route to construct advanced heteroatom doped carbonaceous materials, but also explores the interrelation between zinc ions storage behavior and structural characteristics of carbon materials.

Synthesis of a new three-dimensional cross-linked network dust suppressant and its mechanism of coal-dust inhibition

A new dust suppressant was proposed and studied by numerical calculations and experiments to control dust. The synthesis of suppressant required three steps. First, Polyvinyl alcohol starch was synthesized by the dehydration condensation of carboxymethyl starch and polyvinyl alcohol under the initiation of ammonium persulfate, requiring 288.8 kJ/mol energy. Second, polyvinyl alcohol caprolactam starch was synthesized by the dehydration condensation of caprolactam and polyvinyl alcohol starch under the initiation of ammonium persulfate, requiring 172.8 kJ/mol of energy. Third, the suppressant had the optimum wetting and bonding effects by 30 g/L polyvinyl alcohol caprolactam starch and 20 g/L sodium dodecylbenzene sulfonate. The suppressant–lignite system exhibited increased hydrogen bonds which were formed between the –OH and –COOH groups of the suppressant and the –OH, –COOH, and –NH2 groups on the coal surface. The solidified layer formed on the coal dust surface did not raise dust at wind speed of 10 m/s.

Furan-derived Schiff base covalent adaptable thermosets with recyclability and anti-flammability

Conventional thermosetting polymers, mostly derived from nonrenewable petroleum resources, are not reprocessable and recyclable due to their highly cross-linked three-dimensional networks and face the disadvantage of high flammability. To solve these issues, in this study, we synthesized a novel Schiff base covalent adaptable thermoset from a furan-derived tri-aldehyde monomer (TMFP) and a furan-derived di-amine monomer (DFDA). The as-prepared TMFP-DFDA-Vitrimer exhibited superior anti-flammability with a high limiting oxygen index (LOI) of 35.0% and a UL-94 V-0 rating, which was attributed to the excellent charring ability. Additionally, TMFP-DFDA-Vitrimer could also be conveniently recycled by chemical decomposition under a mixed hydrochloric acid/tetrahydrofuran (HCl/THF) solution. After recycling for 5 times, the thermal, mechanical, and flame retardant properties of the recycled TMFP-DFDA-Vitrimer retained almost unchanged compared to the original one. This work provides a prime instance to develop advanced thermosetting polymers from abundant furan-based compounds.