High-Performance Supercapacitors Using Compact Carbon Hydrogels Derived from Polybenzoxazine

Polybenzoxazine (PBz) aerogels hold immense potential, but their conventional production methods raise environmental and safety concerns. This research addresses this gap by proposing an eco-friendly approach for synthesizing high-performance carbon derived from polybenzoxazine. The key innovation lies in using eugenol, ethylene diamine, and formaldehyde to create a polybenzoxazine precursor. This eliminates hazardous solvents by employing the safer dimethyl sulfoxide. An acidic catalyst plays a crucial role, not only in influencing the microstructure but also in strengthening the material's backbone by promoting inter-chain connections. Notably, this method allows for ambient pressure drying, further enhancing its sustainability. The polybenzoxazine acts as a precursor to produce two different carbon materials. The carbon material produced from the calcination of PBz is denoted as PBZC, and the carbon material produced from the gelation and calcination of PBz is denoted as PBZGC. The structural characterization of these carbon materials was analyzed through different techniques, such as XRD, Raman, XPS, and BET analyses. BET analysis showed increased surface of 843 m2 g-1 for the carbon derived from the gelation method (PBZGC). The electrochemical studies of PBZC and PBZGC imply that a well-defined morphology, along with suitable porosity, paves the way for increased conductivity of the materials when used as electrodes for supercapacitors. This research paves the way for utilizing heteroatom-doped, polybenzoxazine aerogel-derived carbon as a sustainable and high-performing alternative to traditional carbon materials in energy storage devices.

High-Performance Supercapacitor Electrodes from Fully Biomass-Based Polybenzoxazine Aerogels with Porous Carbon Structure

In recent years, polybenzoxazine aerogels have emerged as promising materials for various applications. However, their full potential has been hindered by the prevalent use of hazardous solvents during the preparation process, which poses significant environmental and safety concerns. In light of this, there is a pressing need to explore alternative methods that can mitigate these issues and propel the practical utilization of polybenzoxazine aerogels. To address this challenge, a novel approach involving the synthesis of heteroatom self-doped mesoporous carbon from polybenzoxazine has been devised. This process utilizes eugenol, stearyl amine, and formaldehyde to create the polybenzoxazine precursor, which is subsequently treated with ethanol as a safer solvent. Notably, the incorporation of boric acid in this method serves a dual purpose: it not only facilitates microstructural regulation but also reinforces the backbone strength of the material through the formation of intermolecular bridged structures between polybenzoxazine chains. Moreover, this approach allows ambient pressure drying, further enhancing its practicability and environmental friendliness. The resultant carbon materials, designated as ESC-N and ESC-G, exhibit distinct characteristics. ESC-N, derived from calcination, possesses a surface area of 289 m2 g-1, while ESC-G, derived from the aerogel, boasts a significantly higher surface area of 673 m2 g-1. Furthermore, ESC-G features a pore size distribution ranging from 5 to 25 nm, rendering it well suited for electrochemical applications such as supercapacitors. In terms of electrochemical performance, ESC-G demonstrates exceptional potential. With a specific capacitance of 151 F g-1 at a current density of 0.5 A g-1, it exhibits superior energy storage capabilities compared with ESC-N. Additionally, ESC-G displayed a more pronounced rectangular shape in its cyclic voltammogram at a low voltage scanning rate of 20 mV s-1, indicative of enhanced electrochemical reversibility. The impedance spectra of both carbon types corroborated these findings, further validating the superior performance of ESC-G. Furthermore, ESC-G exhibits excellent cycling stability, retaining its electrochemical properties even after 5000 continuous charge-discharge cycles. This robustness underscores its suitability for long-term applications in supercapacitors, reaffirming the viability of heteroatom-doped polybenzoxazine aerogels as a sustainable alternative to traditional carbon materials.

The Recent Advances of Polymer-POSS Nanocomposites With Low Dielectric Constant

This study provides a comprehensive overview of the preparation methods for polyhedral oligomeric silsesquioxane (POSS) monomers and polymer/POSS nanocomposites. It focuses on the latest advancements in using POSS to design polymer nanocomposites with reduced dielectric constants. The study emphasizes exploring the potential of POSS, either alone or in combination with other materials, to decrease the dielectric constant and dielectric loss of various polymers, including polyimides, bismaleimide resins, poly(aryl ether)s, polybenzoxazines, benzocyclobutene resins, polyolefins, cyanate ester resins, and epoxy resins. In addition, the research investigates the impact of incorporating POSS on improving the thermal properties, mechanical properties, surface properties, and other aspects of these polymers. The entire study is divided into two parts, discussing systematically the role of POSS in reducing dielectric constants during the preparation of POSS composites using both physical blending and chemical synthesis methods. The goal of this research is to provide valuable strategies for designing a new generation of low dielectric constant materials suitable for large-scale integrated circuits in the semiconductor materials domain.

Bio-based Low-k Polymers at High Frequency Derived from Anethole: Synthesis and the Relationship between the Structures and the Properties

Bio-based polymers have been widely investigated as sustainable low dielectric (low-k) materials in past decades. Nevertheless, a few of the polymers with excellent comprehensive properties have been achieved to satisfy the requirements of high-frequency communication application. In this paper, two fluorinated monomers (BCB-F and 2BCB-F) have been designed and successfully prepared from biomass anethole. The thermal-cross-linkable benzocyclobutene and polyfluorobenzene groups were introduced in order to obtain low-k polymers with good comprehensive properties. A control monomer C1 was prepared from the estragole, the isomer of anethole, to study intensively the effect of structures on properties. Among the thermally cured polymers, cured BCB-F with higher fluoride content shows a comparable dielectric constant (Dk) of 2.62 and lower dielectric loss (Df) of 1.31 × 10-3 at a frequency of 10 GHz, as well as better hydrophobic properties with a water uptake of 0.18%. Such good hydrophobic properties enable it to maintain the good dielectric properties even after being soaked in boiling water for 96 h. Cured 2BCB-F with bifunctional benzocyclobutene groups displays excellent heat resistance with a high glass transition temperature (Tg) of 408 °C and a low coefficient of thermal expansion (CTE) of 52 ppm/°C in the temperature range 30-300 °C. Cured 2BCB-F also shows good dielectric properties with a Dk of 2.61 and a Df of 2.60 × 10-3 at a frequency of 10 GHz. The good comprehensive properties reveal that the anethole-based polymers are suitable candidates as matrix or encapsulation resins for application in electronics and microelectric fields.

Recent Progress of Low Dielectric and High-Performance Polybenzoxazine-Based Composites

With the rapid advancement of intelligent electronics, big data platforms, and other cutting-edge technologies, traditional low dielectric polymer matrix composites are no longer sufficient to satisfy the application requirements of high-end electronic information materials, particularly in the realm of high integration and high-frequency, high-speed electronic communication device manufacturing. Consequently, resin-based composites with exceptional low dielectric properties have garnered unprecedented attention. In recent years, benzoxazine-based composites have piqued the interest of scholars in the fields of high-temperature-resistant, low dielectric electronic materials due to their remarkable attributes such as high strength, high modulus, high heat resistance, low curing shrinkage, low thermal expansion coefficient, and excellent flame retardancy. This article focuses on the design and development of modification of polybenzoxazine based on low dielectric polybenzoxazine modification methods. Studies on manufacturing polybenzoxazine co-polymers and benzoxazine-based nanocomposites have also been reviewed.

Bio-Based Polybenzoxazine-Cellulose Grafted Films: Material Fabrication and Properties

Despite the fact that amino cellulose (AC) is biodegradable, biocompatible, and has excellent film-forming properties, AC films have poor mechanical properties and are not thermally stable. An AC-based composite film prepared from AC and curcumin-stearylamine based benzoxazine (C-st) is reported in order to improve its performance and promote its application. As starting materials, C-st and AC were used to produce a C-st/AC composite film possessing a synergistic property through chemical cross-linking and hydrogen bonds. Two salient features with respect to the curing behavior were obtained. Firstly, the onset of curing was reduced to 163 °C when the benzoxazine monomer was synthesized from fully bio-based precursors (such as curcumin and stearylamine). Secondly, a synergistic effect in curing behavior was obtained by mixing C-st with AC. As a result of tensile tests and thermal analysis, the poly(C-st) benefited the composite films with pronounced mechanical and thermal properties, even at elevated temperatures. There was a 2.5-fold increase in tensile strength compared to the AC film, indicating that the composite films have the potential to be used for functional purposes. These poly(C-st)/AC films with improved mechanical and thermal properties have the ability to replace naturally occurring polymer films in film-related applications.

N-Doped Mesoporous Carbon Prepared from a Polybenzoxazine Precursor for High Performance Supercapacitors

Supercapacitors store energy either by ion adsorption or fast surface redox reactions. The capacitance produced by the former is known as electrochemical double layer capacitance and the latter is known as pseudo-capacitance. Carbon materials are found to be attractive materials for energy storage, due to their various micro-structures and wide source of availability. Polybenzoxazine (Pbz) is used as a source to produce carbon materials, due to the fact that the obtained carbon will be rich in N and O species for enhanced performance. Moreover, the carbon materials were produced via template-free method. In general, activation temperature plays a main role in altering the porosity of the carbon materials. The main purpose of this study is to find the suitable activation temperature necessary to produce porous carbons with enhanced performance. Considering these points, Pbz is used as a precursor to produce nitrogen-doped porous carbons (NRPCs) without using any template. Three different activation temperatures, namely 700, 800 and 900 °C, are chosen to prepare activated porous carbons; NRPC-700, NRPC-800 and NRPC-900. Hierarchical micro-/ meso-/macropores were developed in the porous carbons with respect to different activation temperatures. PBz source is used to produce carbons containing heteroatoms and an activation process is used to produce carbons with desirable pore structures. The surface morphology, pore structure and binding of heteroatoms to the carbon surface were analyzed in detail. NRPCs produced in this way can be used as supercapacitors. Further, electrodes were developed using these NRPCs and their electrochemical performance including capacitance, specific capacitance, galvanic charge/discharge, impedance, rate capability are analyzed. The obtained results showed that the activation temperature of 900 °C, is suitable to produce NRPC with a specific capacitance of 245 F g⁻¹ at a current density of 0.5 A g⁻¹, that are attributed to high surface area, suitable pore structure and presence of heteroatoms.

A sustainable strategy for the remediation of oil/water separation using polybenzoxazine/stearic acid functionalized porous carbon

Fabrication of superhydrophobic and superoleophilic polybenzoxazine-stearic acid based melamine sponge for industrial oil/water pollution treatments.

Development of sustainable and antimicrobial film based on polybenzoxazine and cellulose

A new class of bio based polymer blends have been prepared from a modified chitosan based benzoxazine precursor (E-ch) and amino cellulose (AC). AC was derived from cellulose with excellent film-forming, biocompatibility and biodegradability property. E-ch was synthesized from eugenol, modified chitosan and paraformaldehyde. The chemical structure was confirmed by FT-IR and ¹H NMR analyses. Bio films were prepared by mixing E-ch and AC with diluted acetic acid, in different ratios. These films were further cross-linked by applying heat, via ring-opening polymerization of benzoxazine without any curing agent. FT-IR and DSC were used to study the effects of AC on E-ch to form cross-linked network polymer films [poly(E-ch)/AC]. Hydrogen bonding interactions were found to exist between poly(E-ch) and AC. These kinds of interactions considerably improve the mechanical and thermal properties and char yield of the polymer films. Additionally, these biofilms; poly(E-ch) and poly(E-ch)/AC have been examined for bio-activity with S. aureus. It is confirmed that these bio-films are effective in inhibiting bio-film related infection. In a similar way, both the bio-films act against C. albicans and thus avoid the formation of mycological infection. These results expose that poly(E-ch) and AC bio-films are capable to act as anti-microbial and anti-fungal agents.

Cardanol and Eugenol Sourced Sustainable Non-halogen Flame Retardants for Enhanced Stability of Renewable Polybenzoxazines

Olefin bonds participate in co-reaction with the benzoxazine functionality of the monomer and are one of the strategies used to affect the crosslink density of a polybenzoxazine network. In general, the double bond incorporation in starting material is usually catalyzed by expensive, rare earth metals affecting the sustainability of the reaction. The natural abundance of feedstocks with inherent double bonds may be a powerful platform for the development of novel greener structures, with potential applications in polymers. Here, we report the design, synthesis, and characterization of a biobased non-halogen flame retardant, consisting of naturally occurring phenols, eugenol (E), and cardanol (C). The presence of a covalently linked phosphazene (P) core allowed the synthesis of hexa-functional flame retardant molecules, abbreviated as EP and CP. The chemical structures of the synthesized EP and CP were confirmed by Fourier transform infrared (FTIR), nuclear magnetic resonance (¹H, ¹³C, ³¹P NMR), and single crystal XRD (only in the case of EP). Their polymerization with cardanol sourced tri-oxazine benzoxazine monomer, C-trisapm, was followed by FTIR, NMR, and DSC studies. The thermal stability and flame retardant properties of the hybrid phosphazene-benzoxazine copolymers was determined by thermogravimetry analysis (TGA), limiting oxygen index (LOI), vertical burning, and smoke density analyses. SEM images of the char residues of the polymers with or without the addition of reactive phosphazene molecules confirmed the intumescent flame retarding mechanism. Current work highlights the utility of sustainable origin non-halogen flame retardant (FR) molecules and their utility in polybenzoxazine chemistry.

Investigating the effects of amine-functionalized carbon balls in a polybenzoxazine matrix

This study contains arithmetical and experimental examinations of the effects of adding carbon nanoballs (CBs) on the curing behavior and material properties of a benzoxazine system.

Fabrication of ZnO nanoparticles adorned nitrogen-doped carbon balls and their application in photodegradation of organic dyes

In the present study, a novel ZnO nanoparticles adorned nitrogen-doped carbon balls (ZnO@CBs) were successfully synthesized from polybenzoxazine and ZnO nanoparticles through a simple carbonization method. The typical wurtzite hexagonal zinc oxide phase in ZnO@CBs and degree of graphitization were revealed by the X-ray diffraction pattern. The field emission scanning electron microscopy confirmed that the synthesized carbon materials have well dispersed ball-like structure, wherein, the ZnO nanoparticles are distributed evenly on the carbon balls (CBs). The synthesized ZnO@CBs with different wt.% (20, 40, 60 and 80) and bare ZnO nanoparticles were investigated for methylene blue (MB) dye degradation experiment. The synthesized ZnO@CBs exhibited high activity in the degradation of MB. Among the different wt.% of ZnO@CBs, 60 wt.% of ZnO@CBs showed the highest MB degradation ratio (99%) with a fast degradation rate (1.65% min⁻¹) under the following optimum conditions: 20 mg of ZnO@CBs in 50 mL of MB solution at room temperature.

Correction: Replacing bisphenol-A with bisguaiacol-F to synthesize polybenzoxazines for a pollution-free environment

Correction for ‘Replacing bisphenol-A with bisguaiacol-F to synthesize polybenzoxazines for a pollution-free environment’ by Thirukumaran Periyasamy et al., New J. Chem., 2016, 40, 9313–9319.

Biobased Benzoxazine Derived from Daidzein and Furfurylamine: Microwave-Assisted Synthesis and Thermal Properties Investigation

A biobased benzoxazine resin (Dz-f) demonstrating excellent thermal properties was synthesized from daidzein and furfurylamine by using a microwave heating method. The chemical structure of synthesized benzoxazine monomer was identified by FTIR and NMR (¹ H and ¹³ C NMR) before it was cured and its thermal properties evaluated by differential scanning calorimetry (DSC), TGA, and dynamic mechanical analysis (DMA). The cured resin p(Dz-f) exhibited a glass transition temperature (T_g ) of 391 °C, a very high char yield of 68.7 %, and outstanding thermal stability; the T_g value obtained was the highest thermal stability value ever reported for polybenzoxazine with a high biobased content. Moreover, Dz-f demonstrated a satisfying processability, which was rare for the high-performance thermosetting resins. This work provided us with a new strategy for the preparation of high biocontent resins with excellent thermal properties. In addition, the combination of biobased feedstocks with a microwave-assisted heating method as well as the potential application of this approach in high-end fields might perpetuate remarkable progress towards the sustainable development of the polymeric industry.

Synthesis of Eugenol-Based Silicon-Containing Benzoxazines and Their Applications as Bio-Based Organic Coatings

In this work, several bio-based main-chain type benzoxazine oligomers (MCBO) were synthesized from eugenol derivatives via polycondensation reaction with paraformaldehyde and different diamine. Afterwards, their chemical structures were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance Spectroscopy (1H-NMR). The curing reaction was monitored by Differential Scanning Calorimetry (DSC) and FT-IR. The polybenzoxazine films were prepared via thermal ring-opening reaction of benzoxazine groups without solvent, and their thermodynamic properties, thermal stability, and coating properties were investigated in detail. Results indicated that the cured films exhibited good thermal stability and mechanical properties, showing 10% thermal weight loss (Td10%) temperature as high as 408 °C and modulus at a room temperature of 2100 MPa as well as the glass transition temperature of 123 °C. In addition, the related coatings exhibited high hardness, excellent adhesion, good flexibility, low moisture absorption, and outstanding solvent resistance.

Preparing Mn(iii) salen-type Schiff base complexes using 1,3-oxazines obtained by Mannich condensation: towards removing ortho-hydroxyaldehydes

Synthesis of Mn(iii)-salen type Schiff base complexes from 1,3-oxazines obtained from Mannich condensation. This method eliminates the restrictions on the use ofortho-hydroxyaldehydes.

Polybenzoxazine/Polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites

The organic/inorganic hybrid materials from polyhedral oligomeric silsesquioxane (POSS, inorganic nanoparticles) and polybenzoxazine (PBZ) have received much interesting recently due to their excellent thermal and mechanical properties, flame retardance, low dielectric constant, well-defined inorganic framework at nanosized scale level, and higher performance relative to those of non-hybrid PBZs. This review describes the synthesis, dielectric constants, and thermal, rheological, and mechanical properties of covalently bonded mono- and multifunctionalized benzoxazine POSS hybrids, other functionalized benzoxazine POSS derivatives, and non-covalently (hydrogen) bonded benzoxazine POSS composites.

Biomass Vanillin-Derived Polymeric Microspheres Containing Functional Aldehyde Groups: Preparation, Characterization, and Application as Adsorbent

The contribution reports the first polymeric microspheres derived from a biomass, vanillin. It reacted with methacryloyl chloride, providing monomer vanillin methacrylate (VMA), which underwent suspension polymerization in aqueous media and yielded microspheres in high yield (>90 wt %). By controlling the N2 bubbling mode and by optimizing the cosolvent for dissolving the solid monomer, the microspheres were endowed with surface pores, demonstrated by SEM images and mercury intrusion porosimetry measurement. Taking advantage of the reactive aldehyde groups, the microspheres further reacted with glycine, thereby leading to a novel type of Schiff-base chelating material. The functionalized microspheres demonstrated remarkable adsorption toward Cu(2+) (maximum, 135 mg/g) which was taken as representative for metal ions. The present study provides an unprecedented class of biobased polymeric microspheres showing large potentials as adsorbents in wastewater treatment. Also importantly, the reactive aldehyde groups may enable the microspheres to be used as novel materials for immobilizing biomacromolecules, e.g. enzymes.

Synthesis and characterization of hyperbranched polyether imides based on 1,3,5-tris[4-(4′-aminophenoxy)phenoxy]benzene

A new triamine monomer 1,3,5-tris[4-(4′-aminophenoxy)phenoxy]benzene, was synthesized by a three step process using hydroquinone, 1-chloro-4-nitrobenzene and 1,3,5-trichlorobenzene.

Shape memory effect on the formation of oxazoline and triazine rings of BCC/DGEBA copolymer

The development of shape memory polymer by the copolymerization of 1,3-bis(4-cyanatophenyl) cyclohexane cyanate ester and DGEBA through the formation of oxazoline and triazine ring without using any external flexibilizer/plasticizer.

Fabrication and properties of hybrid Mo-CPF/P1B from cardanol

A Mo-CPF/P₁B hybrid has been prepared from molybdenum modified cardanol phenolic resin (Mo-CPF) and cardanol benzoxazine with phosphorus (P₁B).

Cardanol benzoxazines – interplay of oxazine functionality (mono to tetra) and properties

Cardanol, an agrowaste – solventless synthesis and processability of benzoxazine monomers. Tailoring the polymer properties as a function of oxazine functionality in the monomers.