Search Results (15)

In this study, the blends of bio-based polybenzoxazine (V-fa type) and poly(ethylene glycol) (PEG) with PEG contents from 50 to 95 wt% and different molecular weights were developed to improve the flexibility of thermosetting polymers. Of these blends, PEG 8k at 80 wt%, which exhibited the best processability, was selected for further development via compositing with carbon black (CB) from 0 to 20 phr. Differential Scanning Calorimetry (DSC) analysis revealed that the melting temperature (T_m) increased from 70 to 83 °C and glass transition temperatures (T_g) increased from –53 to –48 °C at 20 phr. Thermogravimetric Analysis (TGA) demonstrated high thermal stability, with T_dmax (for all CB contents) presented at ca. 416 °C. Moreover, char yield was increased from 10% (without CB) to 28% (20 phr), reflecting improved decomposition resistance. Mechanical properties demonstrated that CB significantly reinforced the composites. The flexural modulus and flexural strength were increased from 117.18 MPa (without CB) to 456 MPa (10 phr) and from 2.42 MPa (without CB) to 3.94 MPa (2.5 phr), respectively. The SEM images confirmed uniform morphology and good filler dispersion. Conclusively, the composites of 8k PEG 80 wt% filled with 2.5 phr of CB provided an optimal balance of mechanical and thermal stability and engineering polymer applications. Full article

A new type of glass fiber (GF)-reinforced bio-derived polybenzoxazine (GF/bio-derived PBz) composites suitable for dental post applications was developed. The study assessed the effects of different quantities of GF on the mechanical and thermal characteristics, thermal stability, and flame resistance of the composite samples. Additionally, the feasibility of using GF/bio-derived PBz composites for dental posts was analyzed through finite element analysis (FEA). The stress distribution in a tooth model repaired with the newly developed GF/bio-derived PBz composite posts under oblique loads was compared to models repaired with conventional glass fiber post and gold alloy post. The incorporation of GFs significantly enhanced the flexural properties, thermal stability, and flame resistance of the composite samples, while also reducing thermal expansion in a manner that closely matched that of dentin. The FEA of a tooth model repaired with a composite post derived from GF/bio-based PBz revealed a stress distribution pattern comparable to that of a tooth model repaired using a conventional glass fiber post. Considering the composite’s mechanical properties, thermal stability, flame resistance, and its suitability for dental fiber posts as demonstrated by the FEA, the GF/bio-derived PBz holds significant promise for use in dental fiber post applications. Full article

Polybenzoxazines (PBzs), a class of high-performance thermosetting polymers, have gained significant attention for their exceptional thermal stability, mechanical properties, and chemical resistance, making them ideal for aerospace, electronics, and biomedical applications. Recent advancements emphasize their antimicrobial potential, attributed to unique structural properties and the ability to incorporate bio-active functional groups. This review highlights the synthesis, antimicrobial mechanisms, and applications of PBzs and their bio-based derivatives, focusing on sustainable materials science. PBzs demonstrate antimicrobial efficacy through mechanisms such as hydrophobic surface interactions and reactive functional group formation, preventing microbial adhesion and biofilm development. The incorporation of functional groups like amines, quaternary ammonium salts, and phenolic moieties disrupts microbial processes, enhancing antimicrobial action. Modifications with metal nanoparticles, organic agents, or natural bio-actives further augment these properties. Notable bio-based benzoxazines include derivatives synthesized from renewable resources like curcumin, vanillin, and eugenol, which exhibit substantial antimicrobial activity and environmental friendliness. Hybrid PBzs, combining natural polymers like chitosan or cellulose, have shown improved antimicrobial properties and mechanical performance. For instance, chitosan-PBz composites significantly inhibit microbial growth, while cellulose blends enhance film-forming capabilities and thermal stability. PBz nanocomposites, incorporating materials like silver nanoparticles, present advanced applications in biomedical and marine industries. Examples include zirconia-reinforced composites for dental restoration and urushiol-based PBzs for eco-friendly antifouling solutions. The ability to customize PBz properties through molecular design, combined with their inherent advantages such as flame retardancy, low water absorption, and excellent mechanical strength, positions them as versatile materials for diverse industrial and medical applications. This comprehensive review underscores the transformative potential of PBzs in addressing global challenges in antimicrobial material science, offering sustainable and multifunctional solutions for advanced applications. Full article

The development of innovative, cost effective, and biocompatible sensor materials for rapid and efficient practical applications is a key area of focus in electroanalytical chemistry. In this research, we report on a novel biocompatible sensor, made using a unique polybenzoxazine-based carbon combined with amino cellulose and hyaluronic acid to produce a bio-polymer complex (PBC-ACH) (polybenzoxazine-based carbon with amino cellulose and hyaluronic acid). This sensor material is fabricated for the first time to enable the electroreduction of the herbicide, metribuzin (MTZ). The PBC-ACH sensor presents multiple advantages, including ease of fabrication, excellent biocompatibility, and low-cost production, making it suitable for various applications. In optimized experimental conditions, the sensor was fabricated by modifying a glassy carbon electrode (GCE) with the PBC-ACH complex, resulting in the creation of a GCE/PBC-ACH electrode. This modified electrode demonstrated the ability to detect MTZ at nanomolar levels, with an LoD of 13.04 nM, showcasing a high sensitivity of 1.40 µA µM⁻¹ cm⁻². Moreover, the GCE/PBC-ACH sensor exhibited remarkable selectivity, stability, and reproducibility in terms of its electrochemical performance, which are essential features for reliable sensing applications. The potential mechanism behind the detection of MTZ using the GCE/PBC-ACH sensor was investigated thoroughly, providing insights into its sensing behavior. Additionally, tests on real samples validated the sensor’s practicality and efficiency in detecting specific analytes. These findings emphasize the potential of the GCE/PBC-ACH sensor as a highly effective electrochemical sensor, with promising applications in environmental monitoring and other fields requiring precise analyte detection. Full article

In this research, blends of bio-based polybenzoxazine (V-fa) and polycaprolactone (PCL) with different molecular weights (M_n) (14,000, 45,000, and 80,000 Da) were prepared with varying PCL content from 10 to 95 wt%. The spectra measured using Fourier Transform Infrared Spectroscopy (FTIR) may indicate the presence of hydrogen bonding between two polymeric components. The thermograms obtained using a Differential Scanning Calorimeter (DSC) and dynamic mechanical analyzer (DMA) exhibited a shift in glass transition temperature (T_g), which indicated partial miscibility between V-fa and PCL. The thermograms obtained using a thermogravimetric analyzer (TGA) revealed that the addition of PCL led to an increase in the maximum decomposition temperature (T_dmax). The tensile strength and modulus decreased with an increase in PCL, thus indicating a decrease in brittleness. Interestingly, only the samples with an M_n of 80,000 Da were bendable. The blends with 80 wt% PCL were revealed to have shape memory behaviors with a shape fixity of approximately 81%. The shape recovery ratio of the blends with 95 wt% PCL was approximately 78%. Full article

In this paper, the bio-based raw material erythritol was used to introduce an acetal structure into the benzoxazine resins. The benzoxazine-based resins containing an erythritol acetal structure could be degraded in an acidic solution and were environmentally friendly thermosetting resins. Compounds and resins were characterized by ¹H nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared (FT-IR) analyses, and melting points were studied by a differential scanning calorimeter (DSC); the molecular weight was analyzed by gel permeation chromatography (GPC). The dynamic mechanical properties and thermal stability of polybenzoxazine resins were studied by dynamic mechanical thermal analysis (DMTA) and a thermogravimetric analyzer (TGA), respectively. The thermal aging, wet-heat resistance, and degradation properties of polybenzoxazine resins were tested. The results showed that the polybenzoxazine resins synthesized in this paper had good thermal-oxidative aging, and wet-heat resistance and could be completely degraded in an acidic solution (55 °C DMF: water: 1 mol/L hydrochloric acid solution = 5:2:4 (v/v/v)). Full article

In this work, a novel bio-based high-performance bisbenzoxazine resin was synthesized from daidzein, 2-thiophenemethylamine and paraformaldehyde. The chemical structure was confirmed using nuclear magnetic resonance spectroscopy (NMR) and Fourier-transform infrared spectroscopy (FT-IR). The polymerization process was systematically studied using differential scanning calorimetry (DSC) and in situ FT-IR spectra. It can be polymerized through multiple polymerization behaviors under the synergistic reaction of thiophene rings with benzopyrone rather than a single polymerization mechanism of traditional benzoxazines, as reported. In addition, thermogravimetric analysis (TGA) and a microscale combustion calorimeter (MCC) were used to study the thermal stability and flame retardancy of the resulting polybenzoxazine. The thermosetting material showed a high carbon residue rate of 62.8% and a low heat release capacity (HRC) value of 33 J/gK without adding any flame retardants. Based on its outstanding capability of carbon formation, this newly obtained benzoxazine resin was carbonized and activated to obtain a porous carbon material doped with both sulfur and nitrogen. The CO₂ absorption of the carbon material at 0 °C and 25 °C at 1 bar was 3.64 mmol/g and 3.26 mmol/g, respectively. The above excellent comprehensive properties prove its potential applications in many advanced fields. Full article

Candida albicans are highly widespread pathogenic fungi in humans. Moreover, its developed biofilm causes serious clinical problems, leading to drug failure caused by its inherent drug tolerance. Hence, the inhibition of biofilm formation and virulence characteristics provide other means of addressing infections. Polymer composites (PCs) derived from natural products have attracted increasing interest in the scientific community, including antimicrobial applications. PCs are a good alternative approach to solving this challenge because of their excellent penetration power inside biofilms. The main objectives of this study were to synthesize a novel curcumin-based polybenzoxazine polymer composite (poly(Cu-A) PC) using Mannich condensation reaction and evaluate their potency as an antibiofilm and anticorrosive candidate against C. albicans. In addition, their anticorrosive efficacy was also explored. PC exhibited significant antibiofilm efficacy versus C. albicans DAY185 by the morphologic changing of yeast to hyphae, and>90% anticorrosive efficacy was observed at a higher dose of PC. These prepared PC were safe in vivo against Caenorhabditis elegans and Raphanus raphanistrum. The study shows that a polybenzoxazine polymer composite has the potential for controlling biofilm-associated fungal infections and virulence by C. albicans, and opens a new avenue for designing PCs as antifungal, anticorrosive agents for biofilm-associated fungal infections and industrial remediation. Full article

Polybenzoxazines (Pbzs) are considered as an advanced class of thermosetting phenolic resins as they overcome the shortcomings associated with novolac and resole type phenolic resins. Several advantages of these materials include curing without the use of catalysts, release of non-toxic by-products during curing, molecular design flexibility, near-zero shrinkage of the cured materials, low water absorption and so on. In spite of all these advantages, the brittleness of Pbz is a knotty problem that could be solved by blending with other polymers. Chitosan (Ch), has been extensively investigated in this context, but its thermal and mechanical properties rule out its practical applications. The purpose of this work is to fabricate an entirely bio-based Pbz films by blending chitosan with benzoxazine (Bzo), which is synthesized from curcumin and furfuryl amine (curcumin-furfurylamine-based Bzo, C-fu), by making use of a benign Schiff base chemistry. FT-IR and ¹H-NMR spectroscopy were used to confirm the structure of C-fu. The impact of chitosan on benzoxazine polymerization was examined using FT-IR and DSC analyses. Further evidence for synergistic interactions was provided by DSC, SEM, TGA, and tensile testing. By incorporating C-fu into Ch, Ch-grafted-poly(C-fu) films were obtained with enhanced chemical resistance and tensile strength. The bio-based polymer films produced inhibited the growth of Staphylococcus aureus and Escherichia coli, by reversible labile linkages, expanding Ch galleries, and releasing phenolic species, which was 125 times stronger than bare Ch. In addition, synthesized polybenzoxazine films [Ch/Poly(C-fu)] showed significant dose-dependent antibiofilm activity against S. aureus and E. coli as determined by confirmed by confocal laser scanning microscopy (CLSM). This study suggests that bio-based Ch-graft-polymer material provide improved anti-bacterial property and characteristics that may be considered as a possibility in the near future for wound healing and implant applications. Full article

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. Full article

Polybenzoxazine (PBa) composites based on phosphorous-containing bio-based furfurylamine type benzoxazines (D-fu) and bisphenol-A type benzoxazines (Ba) were developed for flame retardation. The structure of D-fu was analyzed by Fourier transform infrared (FTIR) spectroscopy and ¹H-NMR spectroscopy. The curing temperature of Ba/D-fu mixtures was systematically studied by differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) demonstrated the excellent char formation ability of the PBa composites with the addition of phosphorous-containing D-fu. The flame retardancy of the PBa composite materials was tested by the limited oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter (CONE). The LOI and UL-94 level of PBa/PD-fu-5% reached 34 and V0 rate, respectively. Notably, the incorporation of 5% D-fu into PBa led to a decrease of 21.9% at the peak of the heat-release rate and a mass-loss reduction of 8.0%. Moreover, the fire performance index increased, which demonstrated that the introduction of D-fu can diminish fire occurrence. The role of D-fu in the condensed and gas phases for the fire-resistant mechanism of the PBa matrix was supported by SEM-EDS and TGA/infrared spectrometry (TG-FTIR), respectively. Dynamic mechanical analysis (DMA) revealed that the Tg of PBa flame-retardant composites was around 230 °C. Therefore, PBa composites are promising fire-retardant polymers that can be applied as high-performance functional materials. Full article

Due to their outstanding and versatile properties, polybenzoxazines have quickly occupied a great niche of applications. Developing the ability to polymerize benzoxazine resin at lower temperatures than the current capability is essential in taking advantage of these exceptional properties and remains to be most challenging subject in the field. The current review is classified into several parts to achieve this goal. In this review, fundamentals on the synthesis and evolution of structure, which led to classification of PBz in different generations, are discussed. Classifications of PBzs are defined depending on building block as well as how structure is evolved and property obtained. Progress on the utility of biobased feedstocks from various bio-/waste-mass is also discussed and compared, wherever possible. The second part of review discusses the probable polymerization mechanism proposed for the ring-opening reactions. This is complementary to the third section, where the effect of catalysts/initiators has on triggering polymerization at low temperature is discussed extensively. The role of additional functionalities in influencing the temperature of polymerization is also discussed. There has been a shift in paradigm beyond the lowering of ring-opening polymerization (ROP) temperature and other areas of interest, such as adaptation of molecular functionality with simultaneous improvement of properties. Full article

This work details the scalable and solventless synthesis of a potential fully biobased monobenzoxazine resin derived from tyrosol and furfurylamine. The structure of the monomer was studied by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FTIR). The curing of the precursors was characterized by differential scanning calorimetry (DSC), rheological measurements, and thermogravimetric analysis (TGA). The properties of the resulting biobased polybenzoxazine were then determined by thermogravimetric analysis (TGA) and dynamic mechanical thermal analysis (DMA). A thermally stable resin was obtained with 5% and 10% weight-reduction-temperature (T_d5 and T_d10) values of 349 and 395 °C, respectively, and a char yield of 53%. Moreover, the low melting temperature, low viscosity, and excellent thermomechanical behavior make this fully biobased resin a promising candidate for coating applications. Full article

A novel resveratrol-based bio-benzoxazine monomer (RES-al) containing an allyl group has been synthesized using resveratrol, allylamine, and paraformaldehyde via Mannich condensation reaction, and its chemical structures have been characterized by FT-IR spectroscopy and NMR techniques. The polymerization behavior of this benzoxazine resin has been investigated using in situ FT-IR and differential scanning calorimeter (DSC) measurements, and the thermal-mechanical properties of its corresponding polybenzoxazines are evaluated by DMA and TGA. We show that by controlling the curing process of the oxazine ring, the C=C bond in resveratrol, and the allyl group in RES-al, the cross-linking network of the polybenzoxazine can be manipulated, giving rise to tunable performance of thermosets. As all curable functionalities in RES-al are polymerized, the resulted polybenzoxazine exhibits a good thermal stability with a Tg temperature of 313 °C, a T_d5 value of 352 °C, and char yield of 53% at 800 °C under N₂. Full article

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 (T_d10%) 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. Full article