Polybenzoxazine Composites Research Articles

Synergetic control of multi‐level interface structure of basalt fibers by plasma and chemical functionalization to enhance the mechanical, thermal and interfacial performances of PBZ composites

AbstractThe composites of polybenzoxazine (PBZ) containing functionalized plasma treatment basalt fibers (fP‐BFs) were fabricated through in‐situ polymerization‐mixing technique. fP‐BFs is an effective reinforcement material that can improve the mechanical, thermal, and interfacial properties of composites. Surface activation of fP‐BFs can be enhanced through plasma modification, which improves the interaction between fP‐BFs and 3‐aminopropyltriethoxysilane. A systematic study on fP‐BFs/PBZ composite showed that a processing power of 300 W, a processing time of 5 min, and a fiber content of 9% can achieve good comprehensive mechanical properties. Thermogravimetric analysis results showed that fP‐BFs‐7/PBZ has the highest thermal stability, and its carbon residue rate, decomposition temperature and thermal decomposition activation energy are 36.80%, 452.2 °C and 133.56 kJ/mol, respectively. The dynamic mechanical analysis experiment showed that the addition of fP‐BFs improved the Tg of the composites. Among them, fP‐BFs‐5/PBZ showed the highest Tg, reaching 233.2 °C.Highlights Plasma treatment produced multi‐level structure of basalt fibers (fP‐BFs). Polybenzoxazine (PBZ)/fP‐BFs composites showed excellent performance. Interfacial bonding mechanism between fP‐BFs and PBZ was elucidated. Interfacial interactions between BFs and PBZ contributed to property enhancement. This work provided a green fabrication strategy of PBZ composites.

Biocompatibility, thermal and mechanical properties of glass fiber‐reinforced polybenzoxazine composites as a potential new endodontic post

AbstractA novel dental fiber post from glass fiber‐reinforced polybenzoxazine (PBZ) composites was developed in this work. The essential properties, that is, chemical characteristics, thermal and biological properties of the PBZ composites were investigated for various glass fiber loadings (10.5, 23.7, 41.2 and 65.1 vol%). Finite element analysis (FEA) was also utilized to observe mechanical behaviors of the tooth model repaired with PBZ composite posts compared to a natural tooth model. The findings reveal that for the fiber‐reinforced PBZ composites not only their thermal properties were significantly improved, but they also showed enhanced cytocompatibility; we found a coefficient of thermal expansion of 12.8 ppm/°C and cell viability of 91.55 for the 65.1 vol% glass fiber‐reinforced PBZ composite. Moreover, samples reinforced with higher glass fiber loadings effectively resulted in the reduction of stress distribution in dentin observed from FEA suggesting protection againt root fractures. Restoration using the PBZ composite post showed the same stress patterns in the dentin‐composite resin‐post interface of the repaired tooth as in the natural tooth model. The results revealed that the glass fiber‐reinforced PBZ composites possess good thermal properties and mechanical behaviors which renders them suitable candidates for biocompatible dental materials.Highlights The glass fiber/polybenzoxazine (GF/PBZ) composites had nontoxic properties as evidenced through cell viability, growth and morphology studies. The thermal expansion of the GF/PBZ composite was similar to that of dentin, promoting adaptation at the dentin‐post interface. Mechanical behaviors evaluated by FEA of tooth model restored with GF/PBZ composite post were similar to those restored with commercial glass fiber post. The biocompatible GF/PBZ composite with good thermal and mechanical properties is a promising new candidate material as dental fiber post.

Eco‐friendly bio‐based polybenzoxazine composites derived from sustainable thymol: A versatile approach and multifaceted study for enhanced applications

AbstractThis work studied the sustainable approach for the development of bio‐based polybenzoxazine composites derived from sustainable thymol and utilized for diverse applications viz., superhydrophobic, high dielectric, and resistant to bacterial corrosion. The molecular structure of benzoxazines was ascertained from spectral analyses and curing behavior was assessed using differential scanning calorimetry (DSC) analysis. The benzoxazines were polymerized through ring‐opening polymerization to assess their thermal stability using TGA. Among the synthesized polybenzoxazines, the poly(BT‐fa) developed using bis‐thymol (BT) and furfurylamine (fa) which possesses the furfural core contributes to higher thermal stability with the enhanced value of char yield of 43%. Thus, poly(BT‐fa) was chosen for the preparation of composites, and found that 15 wt% chicken feather carbon (CFC) and 15 wt% cashew nutshell cake carbon (CSC) used as reinforcements exhibit significantly enhanced decomposition temperature with char yield of 77% and 69% respectively. Dielectric performance of the composites with high k values of 7.66 and 8.66 was obtained for 15 wt% of the CFC and CSC bio‐carbon reinforcements respectively. These bio‐based benzoxazines also exhibited substantial antibacterial activity, indicating their potential utility toward resistance against microbial colonization. Among polybenzoxazines, poly(BT‐sa) exhibits the highest value of water contact angle (WCA) of 151°. To exploit the superhydrophobic properties of polybenzoxazines, the cotton fabrics were coated with poly(BT‐sa). It was found that poly(BT‐sa) coated cotton fabric possesses an excellent WCA value of 161°, which indicates its suitability for self‐cleaning and water‐repellent applications. Further, poly(BT‐oa) possesses enhanced anti‐corrosion‐resistant behavior than that of other polybenzoxazines and contributes to better protection of mild steel surfaces from corrosion. The values of tensile modulus /flexural modulus and tensile strength and flexural strength obtained for poly(BT‐fa) are 5.1/3.7 GPa and 66 ± 1/103 ± 1 MPa, respectively. Data obtained for bi‐functional bio‐based polybenzoxazine composites from different studies suggest that these materials can be used in antimicrobial, superhydrophobic, and corrosion‐resistant applications.

Hybrid benzoxazines from natural bio-phenolics for enhanced thermal stability and hydrophobicity: a study on vermiculite reinforced composites with low dielectric constant

Two series of unsymmetrical hybrid benzoxazines were separately synthesized using combinations of natural bio-phenolic materials, namely cardanol (C) with eugenol (E), vanillin (V), and guaiacol (G) using diaminodiphenylmethane (ddm)/diaminodiphenyl ether (dde) through the well-known Mannich reaction. The synthesized hybrid benzoxazines have a cure temperature between 229 °C and 269 °C. Compared to previous synthesized benzoxazines, vanillin-based benzoxazines (C-dde-V and C-ddm-V) have a lower cure temperature. TGA results show that poly(C-ddm-V) and poly(C-dde-V), two hybrid polybenzoxazines, have superior thermal stability than the other hybrid polybenzoxazines. In order to develop polybenzoxazine composites, different wt% of GPTMS functionalized vermiculite was incorporated with poly(C-ddm-V). The properties of these composites were examined and contrasted with those of a neat matrix. The hybrid polybenzoxazines and composites water contact angle values vary from 136° to 144°, suggesting that all of the hybrid polybenzoxazines and composites have good hydrophobic behavior. On increasing the concentration of vermiculite, the dielectric constant value significantly decreased to a low dielectric constant.

Sustainable Strategies for Fully Biobased Polybenzoxazine Composites from Trifunctional Thymol and Biocarbons: Advancements in High-Dielectric and Antibacterial Corrosion Implementations

Sustainable Strategies for Fully Biobased Polybenzoxazine Composites from Trifunctional Thymol and Biocarbons: Advancements in High-Dielectric and Antibacterial Corrosion Implementations

Development of quinoline-based heteroatom polybenzoxazines reinforced graphitic carbon nitride (GCN) carbonisation composites for emerging supercapacitor applications.

The current research described in this paper, focuses on the development of a new quinoline-based Mannich-type benzoxazine and its use to obtain advanced carbonisation materials with a high energy storage capacity. Based on this, a quinoline-based benzoxazine monomer (Q-xda) was synthesised by a reaction between 8-hydroxyquinoline, xylylenediamine and paraformaldehyde, and it is characterised by FT-IR and 1H-NMR spectroscopy. Composites were prepared from the benzoxazine and variable weight percentages of graphitic carbon nitride (GCN) (i.e., 5, 10, and 15 wt%). The oxazine ring-opening curing process of the polybenzoxazine composites, and its subsequent pyrolysis reaction was performed; and their chemical structures were confirmed using FT-IR spectroscopy. Also, the thermal and morphological characteristics of the composites were evaluated by XRD, thermogravimetric analysis (TGA), and SEM analyses. According to the results of the thermal experiments, adding GCN reinforcement significantly increased the thermal stability and char yield of the resultant composites. Electrochemical, and hydrophobic investigations were also carried out, and the results of these suggesting that the composites reinforced with 15 wt% GCN exhibit the highest dielectric constant (high κ = 10.2) and contact angle (145°). However, all the crosslinked composites demonstrated a remarkable electrochemical performance as pseudocapacitors. The resulting poly(Q-xda) + 15 wt% GCN electrodes showed a higher capacitance and a lower transferred charge resistance (i.e., 370 F g-1 at 6 A g-1 and 20.8 Ω) than the poly(Q-xda) electrode (i.e., 216 F g-1 at 6 A g-1 and 26.0 Ω). In addition, the poly(Q-xda) + 15% GCN exhibited a cycling efficiency of 96.2% even after 2000 cycles. From these results, it can be concluded that the constructed electrodes perform well in electrochemical operations.

Enhanced dielectric and hydrophobic behaviour of aurin based polybenzoxazine dye composites

Herein, three novel bi-functional benzoxazines were synthesized using aurin as the precursor phenol with three different aromatic amines (i.e.) aniline, fluoroaniline, and trifluoromethylaniline with paraformaldehyde through Mannich condensation. The structural confirmation was done using FTIR and proton NMR. The effects of substituents present in the amines on the curing behaviour and thermal stability were studied using DSC and TGA. The aurin based trifluoromethyl substituted benzoxazine shows better thermal stability than that of the other two benzoxazines and it was selected for the preparation of composites with varying weight percentages of graphitic carbon nitride derived from dicyandiamide (Dicy-GCN) to utilize them for high k applications. The dielectric behaviour and thermal properties of both neat polymer matrix and composites were studied and compared. The 15 wt% Dicy-GCN reinforced composite shows the highest dielectric constant value of 10.25, with a low dielectric loss value of 0.046 at 1 MHz frequency. The polybenzoxazine composites developed show better thermal stability and superhydrophobic behaviour than those of neat polybenzoxazine matrix. These properties ascertain that the aurin based bifunctional polybenzoxazines and its composites can be considered for high-performance high k applications.

Mechanical property improvement of recyclable carbon fiber reinforced rigid-flexible polybenzoxazine/silica based polyhexahydrotriazine IPN

Thermosetting resin matrix composites are difficult to degrade due to their irreversible cross-linking structures, which makes carbon fiber composites difficult to recycle and imposes a huge burden on environment. Here we propose a series of recycle rigid-flexible polybenzoxaizne/silicon-based polyhexahydrotriazine interpenetrating network (IPN) resins through sequential controllable curing reaction, among them, polybenzoxazine and polyhexahydrotriazine are hard segments and soft segments, respectively, and these two crosslinked networks are interspersed with each other. The results showed char yields of these resins at 800 °C under N2 are up to 47.6 %. These IPN resins are used as matrix to prepare carbon fiber-reinforced composites, mechanical test results show that these composites exhibit impressive increases in tensile strength, flexural strength and shearing strength, with minimums of 2393.98 MPa, 1204.90 MPa and 111.07 MPa respectively, which are higher than those of carbon fiber reinforced composites reported. Meanwhile, due to the intermolecular hydrogen bonding, the IPN composites showed maximum water drop angle reached 129.1°, which was nearly 15° higher than that of polybenzoxazine composites. Additionally, these IPN matrix and fibers can be easily recycled from the composites by degradation without damage.

Synthesis and characterization of granite dust microparticles reinforced bio-benzoxazine composites

In the current work, an effort has been made to create polymer composite materials using polybenzoxazine (PBz), which is synthesis from sustainable natural ingredients like furfurylamine (Fu), cardanol (Ca) and reinforced with granite dust made from industrial waste. Varied analytical approaches were used to examine the thermal, morphological, chemical structure, flame retardant and electrical properties of Ca-Fu-PBZ composites reinforced with granite dust at varied weight percentages (5, 10, 15 and 20 wt%). According to the weight percentage concentration of granite dust, the differential scanning calorimetry (DSC) data suggest that the value of Tg increased from 105 to 139°C. A pure Ca-Fu-PBZ benzoxazine matrix was found to have a dielectric constant of 3.97 at 1 MHz. Whereas 5, 10 and 20 wt percentages of reinforced Ca-Fu-PBZ composites with granite dust had dielectric constants of 3.54, 3.05, 2.51 and 2.02 at 1 MHz, respectively. For granite dust reinforced Ca-Fu-PBZ polybenzoxazine composites, the value of the limiting oxygen index (LOI) determined for the char yield obtained thermogravimetric analysis (TGA) shows greater values than those of the neat Ca-Fu-PBZ matrices. Using water contact angle, the hydrophobic behavior of polybenzoxazine composites reinforced with granite dust was investigated, and it was concluded that the hydrophobic behavior increased with the weight % of granite dust. Data from several investigations show that the thermally stable electrical insulation applications can employ the granite dust reinforced sustainable cardanol-furfurylamine based polybenzoxazine composites as potting compounds, sealants and composites.

Polybenzoxazine/organosilicon composites with low dielectric constant and dielectric loss

The evolution of electronic communication technology raises higher requirements for low dielectric constant (low-k) materials. For this, a benzoxazine functional organosilicon (HP-aptes) with dense Si—O—Si crosslinking networks and large sterically hindered tert-butyl groups was prepared by the sol–gel method. Then, a series of polybenzoxazine composites (PPHP) were prepared from intrinsically low dielectric constant bis-functional benzoxazine monomer (P-aptmds) and HP-aptes. The double crosslinking networks of polybenzoxazine and organosilicon further increased the crosslinking density and decreased the dipole density of composites, which endowed the composites with enhanced low-k properties. When the content of HP-aptes is 30% (mass), the crosslinking density was 2.05 × 10−3 mol·cm−3, while that of PP-aptmds was 3.31 × 10−3 mol·cm−3. In addition, the dielectric constant and dielectric loss of PPHP composite at 1 MHz could reach 2.61 and 0.0056, respectively.

Development of hybrid polybenzoxazine composites from sustainable bio-phenol for dielectric and superhydrophobic water repellent utilizations

This study focuses on the synthesis, thermal and dielectric properties of sustainable bio-phenol viz. thymol based polybenzoxazines for applications including low dielectric, high dielectric and water repellent coating applications. By following a simple one-pot method four unique set of thymol benzoxazines were synthesized using varied nature of amines such as laurylamine (l), stearylamine (s), aniline (a), fluoroaniline (f), trifluoromethylaniline (t), cyclohexylamine (c), allylamine (aa), furfurylamine (ff), Jeffmine D230 (j), isophoronediamine (i), methylenebis cyclohexylamine (m), diaminodiphenylmethane (dm), p-phenylenediamine (pp) and diaminodiphenylether (de). The synthesized four set of thymol benzoxazines have been studied for range of applications viz., water repellent coating on cotton fabrics (CFs), low and high k insulation applications. Char yield value of poly(T-de) has been noted as 40% which is greater than the rest of the other synthesized thymol based polybenzoxazines. Amidst the different benzoxazines, highest water contact value (146°) was noticed for poly(T-t). Poly(T-t) coated cotton fabric (CCF) exhibits the super-hydrophobic behavior, which shows the water repellent value of 163°. The 15 wt% of palm-flower silica (PFS) reinforced poly(T-ff) composites showed the lowest dielectric constant value of 2.01 with loss factor of 0.0024. Similarly, high k value of 7.80 with loss factor of 0.0021 achieved for 15 wt% of C-gn incorporated poly(T-de). The results from the different studies, the developed thymol polybenzoxazines and composites exhibited an excellent thermal and dielectric properties, making them suitable for sustainable, versatile coatings and microelectronics applications.

Boron doped graphitic carbon nitride (BN‐g‐C3N4) and palm flower ash reinforced pyrimidinone core‐based polybenzoxazine composites for low‐k and high‐k applications

AbstractThe present work provides a facile process route for the syntheses of pyrimidinone‐based benzoxazines by using stoichiometric quantities of pyrimidinone bisphenol (PBU) and paraformaldehyde, which are separately reacted with various types of amines under suitable experimental conditions. The molecular structure, curing characteristics, thermostability, hydrophobic behavior, and dielectric properties were analyzed using appropriate analytical methods. The polymerization temperature (Tp) of monomers such as PBU‐oda, PBU‐cha, PBU‐ffa, PBU‐a, and PBU‐fa was determined by differential scanning calorimetry (DSC), and the Tp values were noted at 205, 198, 203, 218, and 240°C, respectively. The percentage carbon residue at 850°C for poly(PBU‐oda), poly(PBU‐cha), poly(PBU‐ffa), poly(PBU‐a), and poly(PBU‐fa) were analyzed using thermogravimetric analysis (TGA). The water interface angle values for poly(PBU‐oda), poly(PBU‐cha), poly(PBU‐ffa), poly(PBU‐a), and poly(PBU‐fa) was found to be 141°, 134°, 142°, 136°, and 142°, respectively. The results from the dielectric studies indicate that the benzoxazines (PBU‐ffa and PBU‐a) composites reinforced with palm flower silica (PF‐SiO2) and boron nitride‐g‐C3N4 (BN‐g‐C3N4) were found to be suitable for low and high dielectric applications. From these diverse studies, it can be determined that pyrimidinone‐based benzoxazines to be utilized as high‐performance products in the form of encapsulants, potting agents, and composites for automotive and microprocessor applications.Highlights Pyrimidinone core bisphenol has developed through the efficient method. New pyrimidinone core bisphenol based benzoxazine resins have been developed. BN‐g‐C3N4 filled polybenzoxazine composites have prepared for high‐k applications. Palm flower ash filled polybenzoxazine composites have prepared low‐k applications. Thermal and morphological behavior of composites were studied.

Mechanical properties, thermal stability, and mechanism of main‐chain polybenzoxazine composites fabricated based on multi‐scale effects and surface functionalization of graphene oxide nanosheets

AbstractPolybenzoxazine (PBZ) has been recognized as a potential substitute for traditional phenolic resin. However, poor flexibility and low heat resistance limited obviously the application of PBZ. Herein, graphene oxide (GO) nanosheet and its amino‐rich derivatives (fGO‐g‐SiO2) with multi‐scale surfaces were designed, synthesized and incorporated into main‐chain PBZ through in‐situ polymerization to fabricate PBZ composites. The morphology, mechanical properties, and thermal stability of the composites were systematically investigated using x‐ray diffraction (XRD), contact angle tests, field emission scanning electron microscopy (FESEM), tensile and impact tests, and thermogravimetric analysis (TGA). FTIR and XRD analyses confirmed the multi‐scale surfaces of GO derivatives and ordered structures, respectively. The size of the in‐situ grown SiO2and the thickness of GO coated on PBZ were estimated as 6.5 and 19.07 nm, respectively. The contact angle test revealed thatfGO‐g‐SiO2and BZ had the closest solid surface energy of 32.002 and 43.519 mN/m, respectively, among the components of the composites. The impact and tensile evaluation revealed the highest impact, tensile strength and Young's modulus of 16.75 kJ/m2, 107.24 MPa and 3.17 GPa, respectively for 1.2%fGO‐g‐SiO2/PBZ composite. The modified Halpin‐Tsai equation was also utilized to develop a predictive function for the tensile strength. FESEM offGO‐g‐SiO2/PBZ composites indicated that the multi‐scale effect and amination effectively improved the restriction of GO derivatives on crack propagation in PBZ composites and played a more significant role in crack deflection and bridging. In addition, the highest thermal decomposition activation energy of 166.94 kJ/mol was achieved for 1.2%fGO‐g‐SiO2/PBZ composite.HighlightsGraphene oxide (GO) nanosheets were incorporated into main‐chain polybenzoxazine (PBZ) to improve its mechanical properties and heat resistance.GO with multi‐scale structure and amino‐rich interface were designed, synthesized to improve the interface interactions with PBZ matrix.The GO with multi‐scale structure and amino‐rich interface showed excellent similarity in the term of solid surface energy with benzoxazine oligomers.The morphology, mechanical and thermal stability of resulting PBZ composites was systematically investigated by using experimental and mathematical model to elucidate the relationships between the structure and properties.The composites exhibited excellent mechanical and thermal properties, and it is expected to be used as advanced engineering material in demanding environments.

Valorization of agricultural waste to polybenzoxazine-carbon composites: Studies on microstructure, thermal and dielectric properties

Agricultural waste valorization has become a necessity to reduce global warming. In this context, absolute bio-waste derived cardanol, furfurylamine (ffa), and benzaldehyde were utilized for the synthesis of a novel card-bisphenol (BBC) and its benzoxazine (BBC-ffa) resin. Further, the reinforcement of carbon building blocks derived from three different sustainable resources, viz. Anacardium occidentale, Borassus flabellifer, and Tamarindus indica and named cashew apple carbon (CC), palmyra palm inflorescence (spadix) carbon (PC), and tamarind seed carbon (TC), respectively. The derived carbons were reinforced (1–20 wt%) separately with BBC-ffa polymer matrix [poly(BBC-ffa)] for the engineering of carbon integrated polybenzoxazine composites [poly(BBC-ffa)–CC/PC/TC] to achieve high-k dielectrics. Because the carbon with different functionalities intrinsically exhibit higher polarization and lower specific surface area. Dielectric constant (k) of the polybenzoxazine matrix (k = 4.62) has been increased to 8.58, 9.43, 10.60 for the reinforcement of 20 wt% of each CC, PC, and TC polybenzoxazine composites, respectively and the value of dielectric loss was also significantly decreased for the same. The dissemination of reinforced carbon particles in the polybenzoxazine matrix was ascertained through the surface analysis of the composites by FE-SEM. Based on the results of TGA, the carbon reinforced composites showed slightly lower thermal stability and about two-fold higher char yield than that of neat polybenzoxazine. Hydrophobicity of the composites enhanced with increasing the carbon content. The resulting sustainable polybenzoxazine-carbon composites could be effectively utilized as a gate dielectric in microelectronics.

Flame-retardant and anti-corrosion behaviour of cardanol-based polybenzoxazine composites

A new monomer of bi-functional benzoxazine was synthesised using cardanol (C) and p-phenylenediamine (ppda) under suitable experimental conditions. The curing behaviour of the cardanol-based 1,4-bis(7-pentadecyl-2H-benzo[1,3]oxazin-3(4H)-yl)benzene (C-ppda) benzoxazine monomer was studied by differential scanning calorimetry analysis, and the polymerisation temperature (T p) of C-ppda benzoxazine was found to be 237°C. Further, the benzoxazine monomer was reinforced with varying weight percentages (5, 10 and 15 wt%) of bio-ash derived from Aerva lanata (AL-ash) to obtain hybrid composites. Thermogravimetric analysis data indicate that AL-ash-reinforced benzoxazine composites possess excellent thermal stability and a flame-retardant behaviour. The morphology of AL-ash- and cardanol-based benzoxazine composites was analysed using field emission scanning electron microscopy (FESEM). The FESEM results indicate homogeneous distribution of AL-ash in the composites. Energy-dispersive X-ray spectroscopy analysis was used to determine the elemental composition of the AL-ash used for the preparation of composites. The value of the water contact angle of poly(C-ppda) was found to be 148°. Data obtained from corrosion studies indicate that the mild steel specimen coated with a benzoxazine matrix and the specimen coated with bio-ash-reinforced benzoxazine composites exhibit an excellent resistance against corrosion. The bio-ash-reinforced composites of cardanol-based benzoxazine can be used in the form of sealants, encapsulants, adhesives, coatings and matrices in microelectronics and automobile applications under high thermal and moist environmental conditions.

High‐performance main‐chain polybenzoxazine composites by incorporating multi‐walled carbon nanotubes with different surfacial structure: Mechanical properties, thermal stability and mechanisms

AbstractHerein, multi‐walled carbon nanotubes (MWCNTs) with different surfacial structure were first designed and synthesized, and then incorporated into main‐chain polybenzoxazine (PBZ) to fabricate PBZ composites. Fourier transform infrared results showed that the ring‐opening crosslinking process of benzoxazine (BZ) oligomer was catalyzed due to the existence of COOH and NH2 groups on the surface of MWCNTs. The enhanced interface interactions between MWCNTs‐fBZ and PBZ contributed to the improvement of the mechanical properties. When the MWCNTs‐fBZ content was 1.5%, the MWCNTs‐fBZ/PBZ composites had excellent tensile strength of 102.64 MPa. The highest impact strength, which was 15.96 kJ/m2 and 64.15% higher than that of neat PBZ at 1.5% MWCNTs‐fBZ was achieved. Through the Halpin‐Tsai equation, combined with the experimental results, the correction factor was obtained to predict the mechanical properties. FESEM observations showed that the dispersion of MWCNTs in the PBZ matrix depended on the functional groups of MWCNTs. TGA tests and Horowitz‐Metzger calculation found that the thermal decomposition temperature of the composites reached 451.7°C and had the highest decomposition activation energy of 153.20 kJ/mol at 2% MWCNTs‐fBZ. In summary, the obtained MWCNTs‐fBZ/PBZ composite showed excellent comprehensive performance and can potentially be used as advanced engineering material in demanding environments.

Bio-thymol containing new high-performance thymolphthalein based polybenzoxazine: Thermal, superhydrophobic and dielectric properties

An increase of global population and consequent cause of environmental concerns, significant efforts have been made to reducing the use of fossil-based precursors and chemicals. The sustainable bio-benzoxazine resins were prepared using thymolphthalein and different amines systems such as aliphatic amines [butylamine (ba), hexylamine (ha), 2-ethylhexylamine (eha), dodecylamine (dda), octadecylamine (oda)), aryl amines (aniline (a), 4-fluoroaniline (fa), 3-trifluoromethylaniline (tfma)], and miscellaneous amines [cyclohexyamine (cha), allylamine (aa) and furfurylamine (ffa)] with paraformaldehyde through Mannich condensation. The molecular structure of corresponding benzoxazines was analysed using FTIR and 1H NMR spectroscopic techniques. Superhydrophobic cotton cloth was prepared using aliphatic amine based benzoxazine coating. The reinforcements bio-silica from bamboo ash and graphitic carbon nitride (GCN) from melamine precursors were separately prepared and functionalized under appropriate experimental conditions, which are used as reinforcement for the development of polybenzoxazine composites. Thermal stability, morphology and hydrophobicity of cardanol functionalized-GCN and GPTMS functionalized bio-silica reinforced polybenzoxazine composites were studied using TGA, FESEM and goniometer respectively. The poly(THP-oda) coated cotton fabric possesses the value of highest water contact angle of 154°. Further the poly(THP-oda) coated cotton fabric was tested for its efficiency towards oil-water separation. The value of dielectric constant of 15 wt% of bamboo ash silica reinforced poly(THP-ffa) and 15 wt% of C-GCN reinforced poly(THP-tfma) are 1.9 and 7.9 respectively.

Nonylphenol-based polybenzoxazine composites: hydrophobic coating, ultra-low-k and anticorrosion applications

Nonylphenol-based polybenzoxazine composites: hydrophobic coating, ultra-low-k and anticorrosion applications

Synthesis and characterization of cardo-tetrafunctional hydrophobic polybenzoxazine composites for low-k application

Synthesis and characterization of cardo-tetrafunctional hydrophobic polybenzoxazine composites for low-k application

Industrial cutting waste granite dust reinforced cardanol benzoxazine/epoxy resin hybrid composites for high‐voltage electrical insulation applications

AbstractAn attempt has been made to develop hybrid composites from benzoxazine monomer (C‐ddm) hybridized with DGEBA epoxy resin (EP) and reinforced with varying weight percentages (20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt%) of glycidoxypropyltrimethoxy‐ silane (GPTMS) functionalized granite dust (GD) obtained from industrial granite cutting and polishing process in order to utilize them for electrical insulation applications. The thermal stability of granite dust reinforced poly(EP‐co‐C‐ddm) composites was studied by TGA analysis. Among the composites samples studied, 100 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possess better thermal stability than that of other neat matrices and composites. Among the composites prepared using varying weight percentages of functionalized GD reinforcement, it was observed that 80 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possesses better hydrophobic character than that of other neat matrices and composites. The value of LOI calculated for neat matrix (poly[EP‐co‐C‐ddm]) and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% GD reinforced composites was found to be 22, 28, 34, 40, 43 and 45 respectively. The 80 wt% GD reinforced poly(EP‐co‐C‐ddm) composites possess the higher values of tensile strength and flexural strength of 47 MPa and 140 MPa, respectively than those of their samples. The values of electrical surface resistivity and electrical volume resistivity of all the neat matrices and GD reinforced polybenzoxazine composites were found to be in the order of 1012 and 1013 respectively. The values of dielectric strength obtained from break down voltage (BDV) for neat matrix [poly(EP‐co‐C‐ddm)] and 20 wt%, 40 wt%, 60 wt%, 80 wt% and 100 wt% of GD reinforced poly(EP‐co‐C‐ddm) composites are 15.0, 15.5, 16.5, 17.0, 17.0 and 17.0 kV/mm, respectively. Data obtained from thermal stability, hydrophobic behavior and dielectric studies it was inferred that the hybrid polymer composites developed in the present work can be conveniently used in the form insulators, sealants, adhesives and matrices where application demands at high‐performance industrial and engineering applications.