Enhanced Thermal and Mechanical Properties of Boron-Modified Phenolic Resin Composites in a Multifiller System: Potential Applications in Aerospace Materials

doi:10.21203/rs.3.rs-4675224/v1

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Enhanced Thermal and Mechanical Properties of Boron-Modified Phenolic Resin Composites in a Multifiller System: Potential Applications in Aerospace Materials

https://doi.org/10.21203/rs.3.rs-4675224/v1

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The study investigated the properties of boron-modified phenolic resin (BPR) compositess reinforced with glass fiber (GF) and mica, SiO₂ and glass powder (MSG). The BPR/MSG/GF composites exhibited improved mechanical strength, reduced shrinkage, and enhanced insulation properties at high temperatures. Thermogravimetric analysis showed enhanced thermal stability with a residue rate of 89.91% at 800 ℃. The addition of glass powder which is regarded as a fluxing agent, resulted in the densification of the ceramic layer. X-ray diffraction analysis (XRD) demonstrates that mica undergoes eutectic reaction with other fillers and glass powder to form the final ceramic layer. These findings have implications for the development of high-performance compositess with excellent heat resistance and mechanical strength. Further optimization of filler content and processing conditions can enhance the performance of these composites for specific applications.

Boron-modified Phenolic Resin

thermal resistance

mechanical properties

ceramization

Phenolic resin (PR) is a widely utilized polymer material, favored for its easy availability of raw materials, convenient synthesis, affordability, and high bonding strength, which have led to its extensive application in industrial production[1, 2]. Compared to other polymers, PR exhibits superior high-temperature resistance, higher char yield, reduced smoke emissions, and lower toxicity, making it a popular choice in various high-temperature applications[3]. However, its protective capabilities under extreme conditions, such as in rocket and aircraft fuselage paint films, where temperatures and impacts are more severe, are often inadequate. Consequently, the modification of PR to further enhance its high-temperature performance and mechanical properties is of significant interest.

In the molecular structure of conventional PRs, the phenolic hydroxyl groups and methylene bridges are susceptible to oxidation. PRs can be used stably for extended periods at temperatures below 200 ℃. However, if the temperature exceeds 200 ℃, the resin undergoes oxidation, and between 340 ℃ to 360 ℃, it enters the thermal decomposition phase. At temperatures ranging from 600 ℃ to 900 ℃, the resin thermally decomposes, releasing substances such as CO, CO₂, H₂O, and phenol, while undergoing carbonization, which affects its thermal resistance and antioxidative properties. Consequently, many researchers have focused on the functional modification of PRs. In recent years, with the expansion of applications for PRs, extensive and systematic research has been conducted, yielding several new findings. Among these, due to the tendency of PRs to decompose at high temperatures, there has been considerable research on modifications to enhance their high-temperature resistance. The methods for modifying the high-temperature resistance of PRs primarily include the introduction of boron elements[4], silicon elements[5], the synergistic modification by introducing both silicon and boron elements[6], and the incorporation of nanomaterials[7]. Boron modification is a common method for enhancing the heat resistance of PRs[8–11]. By incorporating boron elements into PR via B-O-C bonds, the thermal decomposition temperature and char yield of the resin can be increased[4]. The presence of B-O-C bonds also reduces the content of easily oxidizable phenolic hydroxyl groups, thereby enhancing the heat resistance of the resin[12]. Studies by Wang et al.[13] on the thermal decomposition behavior of boron-modified PR at high temperatures have shown that during the high-temperature curing process, borophenol esters are produced. These esters react with phenolic hydroxyl groups to prevent the thermal decomposition of the cross-linked network, thus improving the material's thermal stability. Moreover, at 400 ℃, borophenol esters consume oxygen to form B₂O₃, which prevents the loss of carbon through CO₂ volatilization, thereby increasing the char yield. Xing et al.[14] identified that the release of volatile organic compounds at 300 ℃, such as monophenols and biphenols formed through the cleavage of terminal C-C single bonds, is a primary reason for the reduction in char yield of PRs at high temperatures. These volatile organic compounds are primarily produced by the cleavage of covalent bonds. In boron-modified PRs, the borate ester bonds formed between boron hydroxyl and phenolic hydroxyl groups increase the molecular weight of small molecules, making them less volatile. The presence of borate ester bonds also alters the thermal decomposition process of PR, reducing the formation of monophenols and biphenols. Thus, the modification of PR with boric acid to enhance its heat resistance is widely utilized.

However, chemical modifications at the molecular level alone are insufficient to maximize the heat resistance of PR. Enhancing or altering the flame-retardant layer formed upon heating, can further improve heat resistance. Ceramization is one effective method to enhance the high-temperature resistance of polymers. Compared to other flame-retardant polymer materials, ceramizable composites exhibit higher thermal stability, non-toxicity, excellent thermal barrier properties, and the ability to retain their shape after the complete degradation of the polymer matrix at high temperatures[15]. Ceramizable materials display polymer characteristics at room temperature but exhibit ceramic properties when heated to a certain extent[16–19]. The mechanical and thermal insulation properties of the ceramic layer formed at high temperatures far exceed those of ordinary char layers, ensuring that the residues obtained after thermal degradation of the composites at high temperatures have a higher density[20–22]. In high temperatures, the ceramizable composites matrix undergoes pyrolysis while the fluxing agent melts. As the temperature increases, the ceramizable fillers gradually decompose, reacting with the char produced by the matrix and the low-melting-point fluxing agent to form a ceramic layer. Agrawal et al.[23] utilized mathematical analysis to calculate the impact of various factors such as the shape and size of filler particles on the effectiveness of the filler. The results demonstrated that the optimal performance of the fillers is achieved when the particle size is below 2 to 3 nm. Regarding the shape of the fillers, disc-shaped particles exhibited superior effectiveness compared to spherical and elliptical particles. Ceramic fillers, depending on their type, can be categorized into mineral fillers, metal oxides, metal hydroxides, and other types of fillers. Mica, a commonly used mineral filler with a layered structure, offers excellent high-temperature resistance, mechanical properties, and dielectric properties. At high temperatures, the original crystal structure of mica is disrupted, and it reacts with the products of matrix pyrolysis and other fillers to form a eutectic mixture, which then creates a rigid ceramic[24]. Glass powder, an amorphous hard particle primarily containing oxides like SiO₂, Al₂O₃, CaO, Na₂O, K₂O, and P₂O₅, reduces the temperature at which ceramics form and creates a more continuous and integral ceramic structure[25, 26]. At temperatures between 300–700 ℃, glass powder gradually melts, filling the gaps between fillers and the pores left by gas expulsion, and connecting the ceramizing fillers to form a continuous ceramic[27].

Fiber-reinforced polymer composites possess several advantages such as low density, high strength, and superior thermal insulation properties. Thus, fiber-reinforced composites are extensively utilized in automobiles, aircraft, spacecraft, ships, civil infrastructure, and wind energy applications[28–32]. Glass fibers (GF), known for their high temperature resistance, corrosion resistance, and lightweight properties, serve as excellent matrix materials for composites, thereby finding applications in the aerospace sector where thermal stability, high temperature resistance, and superior mechanical properties are required. Wagner et al.[33], have conducted experimental and numerical evaluations of different aerospace-grade composites under high-speed impacts, characterizing materials including thermosetting (epoxy resin) and thermoplastic polymers (PEEK), as well as carbon (unidirectional and woven) and GFs. Results indicate that GF composites surpass traditional composites in weight-specific impact performance. Fibers commonly used for modifying PRs include GFs, carbon fibers, and natural hemp fibers[34]. GF, due to its low cost and chemical stability, is widely used as a reinforcement material for PR, enhancing both its mechanical properties and high-temperature resistance[35]. Choe et al.[36] reinforced PR foam with GFs, and the reinforced composites exhibited a maximum tensile strength of 148 kPa, a 28% improvement over pure PR foam. Additionally, the thermal conductivity of the composites was also enhanced. Zhou et al.[37] enhanced phenolic foam with GF mats, which resulted in improved mechanical properties and storage modulus of the reinforced phenolic foam. The enhancements included a 112% increase in tensile strength, a 36% increase in compressive strength, a 48% increase in impact strength, and a 31% increase in storage modulus. However, the coefficient of thermal expansion of the composites exhibited a slight increase compared to the pure phenolic foam. To enhance the bond strength between the GFs and the PR, Kim et al.[38] treated the GFs with a silane coupling agent, which resulted in a 60% increase in the tensile strength of the composites. This demonstrates that treating GFs with a silane coupling agent can effectively enhance the bond strength between the fibers and resin, thereby improving the mechanical properties of the composites.

In this study, boron-modified phenolic resin was employed as the matrix material, with mica, SiO₂, and glass powder serving as fillers, and glass fiber utilized as a reinforcing material, to fabricate a series of ceramizable phenolic resin composites. These composites underwent high-temperature treatment in a tubular furnace, and corresponding yields, char rates, solid contents, and high-temperature dimensional stability were calculated. In the content that follows, boron-modified phenolic resin is abbreviated as BPR. The composite material consisting of boron-modified phenolic resin with mica and SiO₂ fillers, supported by glass fibers, is abbreviated as BPR/MS/GF. Similarly, the composite material that includes mica, SiO₂, and glass powder as fillers, also supported by glass fibers, is designated as BPR/MSG/GF. The thermal conductivity was determined using an HNB-DRS2 type thermal conductivity meter, and thermogravimetric analysis was conducted to analyze thermal weight loss. The impact strength and bending strength of the composites, both before and after high-temperature treatment, were tested using a simply supported beam impact testing machine and a universal mechanical testing machine, respectively. Characterization was performed using Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, field emission scanning electron microscopy (SEM), thermogravimetric-infrared spectroscopy (TG-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction analysis (XRD).

2.1. Materials

Oxalic acid (AR, 99%) and boric acid (AR ≥ 99.5%) were purchased from Tianjin University of Science and Technology Chemical Reagent Factory, Dongli District, Tianjin. Hexamethylenetetramine (AR, 99%) and anhydrous ethanol (AR, ≥ 99.5%) were obtained from Tianjin Tianli Chemical Reagent Co., Ltd. Ethyl acetate (AR, 99.5%) was sourced from Tianjin Fuyu Fine Chemical Co., Ltd. GF cloth was acquired from Jiangsu Zhenjiang Anzhi Shield High Temperature Fiber Products Co., Ltd. Mica powder was procured from Henan Borun Casting Material Co., Ltd. Silicon dioxide (AR, 99%) was obtained from Tianjin Hengxing Chemical Reagent Manufacturing Co., Ltd. Glass powder was purchased from Zhengzhou Yameikai New Materials Co., Ltd. Phenol (AR, > 99%) was sourced from Tianjin Benchmark Chemical Reagents Co., Ltd., and formaldehyde solution (AR, 37 ~ 40% wt) was obtained from Tianjin Comio Chemical Reagents Co., Ltd.

2.2 Synthesis of BPR

In a 250 mL three-necked flask equipped with a thermometer, a reflux condenser, and a mechanical stirrer, 23.50 g of phenol was added. The heating mantle temperature was set to 50 ℃, and upon the melting of phenol, 0.75 g of oxalic acid was introduced. Continuous stirring ensured the uniform dispersion of oxalic acid within the phenol. Subsequently, the temperature of the heating mantle was increased to 100 ℃, and over the course of 1 h, a formaldehyde solution was added dropwise. Stirring was maintained at 100 ℃ for 4 h, followed by the vacuum distillation of the product to remove water from the system. Boric acid was then added to the system, and the reaction was continued for an additional 4 h. Upon completion of the reaction, the system was allowed to cool naturally. When the temperature of the reactants reached 50 ℃, a specified amount of ethyl acetate was added to the flask, and the mixture was stirred at this temperature for 0.5 h to dissolve the product in the solvent. The solution was then transferred into a separatory funnel, washed multiple times with distilled water, and the organic phase was collected back into the flask. The solvent was removed using a rotary evaporator to yield a transparent BPR.

To determine the effect of the formaldehyde-phenol ratio on the performance of the synthesized boron-modified PR, the amount of boric acid added was fixed at a ratio of 1:0.2 to phenol. The ratio of formaldehyde to phenol was varied at 1:1.0, 1:1.2, 1:1.4, 1:1.6, 1:1.8. The specific experimental formulas can be seen in Table S1. In order to determine the effect of the boron-phenol ratio on the synthesis of BPR, the ratio of formaldehyde solution to phenol was fixed at 1:1.2. Boron-modified PR was prepared with the ratio of boric acid to phenol being 1:0.1, 1:0.15, 1:0.2, 1:0.25, and 1:0.3 respectively. The specific experimental formulas can be found in Table S2.

2.3 Synthesis of BPR/MS/GF Composites

Fillers were added to the prepared BPR solution following the proportions detailed in Table S3, with hexamethylenetetramine selected as the curing agent and incorporated at a concentration of 10 wt% into the mixture. The ratio of added mica to SiO₂ was set at 2:1. The system was subjected to mechanical stirring until homogenous, after which the viscosity was adjusted with ethanol. The mixture was then ultrasonically dispersed for 60 minutes in an ultrasonic cleaning bath. Following dispersion, the resin was brush-applied to glass fiber cloths to ensure even impregnation. The impregnated cloths were layered and cured in an oven at 80°C for 30 minutes. After baking, the coated cloths were placed in a flatbed vulcanizing press and hot-pressed according to the protocol depicted in Fig. S1, maintaining a pressure of 10 MPa throughout the process. Upon completion, the temperature was allowed to decrease to room temperature before the laminates were removed and cut to the required dimensions. The preparation process is illustrated in Fig. 1. The optimal formulation ratio of BPR materials, the yield of the carbon layer, solid content, and carbon residue at various formulation ratios presented in Fig. S2

2.4 Synthesis of BPR/MSG/GF Composites

Fillers were added to the prepared BPR solution following the proportions detailed in Table S4, with hexamethylenetetramine selected as the curing agent and incorporated at a concentration of 10 wt% into the mixture. The ratio of added mica, SiO₂ and glass powder was set at 2:1:1. The system was subjected to mechanical stirring until homogenous, after which the viscosity was adjusted with ethanol. The mixture was then ultrasonically dispersed for 60 minutes in an ultrasonic cleaning bath. Following dispersion, the resin was brush-applied to glass fiber cloths to ensure even impregnation. The impregnated cloths were layered and cured in an oven at 80°C for 30 minutes. After baking, the coated cloths were placed in a flatbed vulcanizing press and hot-pressed according to the protocol depicted in Fig. S1, maintaining a pressure of 10 MPa throughout the process. Upon completion, the temperature was allowed to decrease to room temperature before the laminates were removed and cut to the required dimensions. The preparation process is illustrated in Fig. 1.

2.5 Characterization

2.5.1 Structural characterization of BPR

FTIR spectra of BPR, BPR/GF, BPR/MS/GF, and BPR/MSG/GF were captured using a Spectrum 400 FTIR spectrometer in the scan range of 400 to 4000 cm^− 1. The ¹³C NMR spectra of BPR were conducted using a Bruker AV500M NMR spectrometer (Switzerland) with deuterated dimethyl sulfoxide (DMSO-d6) as the solvent. The yield of the synthesized resin was calculated based on the mass of the starting material, phenol, according to the following formula:

$$\:Y=\frac{{m}_{1}}{{m}_{2}}\times\:100\%$$

In the formula, (Y) represents the yield of the resin (%) where (m₁) is the mass of the synthesized resin, and (m₂) is the mass of the raw material phenol.

A crucible of constant weight is taken, weighed as (m₃), and a sample of the resin containing 10 wt% hexamethylenetetramine weighing (4 ± 0.4) g is added, noted as (m₄). The crucible is then placed in an electric blow-drying oven at 120 ℃ until constant weight is achieved. Upon cooling, it is weighed again as (m₅). The solid content (S) is calculated using the following formula:

$$\:S=\frac{{m}_{5}-{m}_{3}}{{m}_{4}}\times\:100\%$$

After testing for solid content, the crucible is placed in a tube furnace at 800 ℃ and calcined for 10 min, cooled, and then weighed. The carbon residue rate is calculated using the following formula:

$$\:C=\frac{{m}_{8}-{m}_{6}}{{m}_{7}}\times\:100\%$$

where (C) represents the carbon residue rate (%) of the resin, (m₆) is the mass of the crucible, m₇ is the mass of the resin sample at room temperature, and m₈ is the mass of the crucible and sample after treatment at 800 ℃.

2.5.2 Physical properties analysis of composites

The impact strength of the composites before and after high-temperature treatment is tested using a simple support beam impact testing machine according to ASTM D256-10 with unnotched plate specimens. Three parallel experiments are conducted, and the average value is taken as the result. The bending strength of the composites before and after high-temperature treatment is tested using a universal testing machine according to ASTM D256-10. Three parallel experiments are conducted, and the average value is taken as the result.

2.5.3 Thermal stability of composites

linear shrinkage expansion rate is calculated using the following formula:

$$\:S=\frac{{L}_{0}-L}{L}\times\:100\%$$

where (S) represents the linear shrinkage expansion rate (%), (L) is the length of the sample before thermal treatment (mm), and (L₀) is the length of the sample after thermal treatment (mm).

Thermogravimetric analysis (TGA) is recorded on a STA449F5 thermal analyzer (NETZSCH, Germany) in air. The sample is heated at a scanning rate of 10 ℃/min.

A vernier caliper is used to measure the length of the laminate before and after high-temperature treatment to calculate its linear shrinkage expansion rate, and a digital camera is used to photograph and observe the material’s dimensional stability.

Thermogravimetric-Infrared (TG-IR) coupling tests on the compositess are performed using a TGA 8000 (PerkinElmer, USA) and an FT-IR Spectrometer Spectrum 3 (PerkinElmer, USA), starting at room temperature and heating at a rate of 10 ℃/min up to 800 ℃; the scanning range is 700–4000 cm^− 1.

2.5.4 Analysis of ceramic properties of composites

XPS was utilized to analyze the composites after exposure to butane flame. The source was a monochromated Al target, and spectra were referenced to the C1s binding energy of sp3 carbon at 284.8 eV.

XRD analysis was conducted on the ceramifiable composites after high-temperature treatment. The X-ray diffractometer used was a TD-3500 model produced by Dandong Tongda Science and Technology Co., Ltd., with a scanning speed of 4.8 °/min and a scanning range of 2θ = 10° to 90°. The samples were in powder form.

The Scanning electron microscope (SEM, EM-30plus, Korea) was carried out to observe surface morphology of BPR/MSG/GF ceramic layer.

3.1 Structural analysis of BPR

The reaction process for the synthesis of thermoplastic PR using phenol and formaldehyde as raw materials, with oxalic acid as the catalyst, and then subsequently incorporate boric acid to form boron-modified PR. The mechanism of forming BPR is depicted in Fig. 1. Under acidic conditions, phenol and formaldehyde undergo an addition reaction followed by rapid condensation. After that, the PR reacts with boric acid.

To verify the successful synthesis of BPR, FTIR and NMR spectroscopy were employed to investigate the chemical structure of BPR. The FTIR spectra of PR and BPR are displayed in Fig. 2a. In the FTIR spectra of both PR and BPR, the stretching vibration peak of -OH groups appear at 3336 cm^− 1; the stretching vibrations of -CH- are observed at 2973 cm^− 1 and 1454 cm^− 1; and the C-O stretching vibration peak of the phenolic hydroxyl groups on the benzene ring is present at 1236 cm^− 1. Notably, an absorption peak for the B-O bond appears at 1335 cm^− 1 in BPR, indicating the esterification of boronic acids with the hydroxyl groups of the PR, which confirms their chemical incorporation into the PR (Table S5).

NMR spectroscopy was further utilized to confirm the structure of BPR, with the ¹³C NMR spectrum presented in Fig. 2b. Peaks between 158.0 and 153.0 ppm correspond to the carbon atoms connected to oxygen atoms on the benzene ring in BPR, while those between 133.0 and 127.0 ppm correspond to the carbon atoms at the meta positions relative to substituents at the ortho and para positions on the benzene ring. Peaks between 120.0 and 115.0 ppm are assigned to the carbon atoms at the ortho or para positions when adjacent or opposite positions are unsubstituted. Additionally, the peak at 60.2 ppm is attributed to the carbon atoms in the -CH₂OH groups in BPR. Furthermore, impurity peaks at 170.8 ppm, 21.1 ppm, and 14.4 ppm, caused by residual ethyl acetate, further confirm the successful synthesis of BPR (Table S6).

3.2 Determination of the optimal addition ratio of BPR/MS/GF Composites and BPR/MSG/GF Composites

The addition of fillers to the composite material serves to facilitate the formation of dense ceramics under high temperatures. Consequently, the optimal quantity of filler is determined based on the impact strength of the material post-treatment at 1000 ℃ for 30 min. A higher impact strength suggests the formation of denser ceramics, which in turn indicates enhanced protective capabilities. To this end, composite materials with various fillers and proportions have been prepared. As depicted in Fig. 3a, the impact strength of the composite material post-treatment at 1000 ℃ initially increases with the addition of fillers, peaking at a 30 wt% filler content. Beyond this point, the impact strength diminishes with further filler incorporation. This behavior can be attributed to the optimal dispersion of filler particles at contents below 30 wt%, where they enhance ceramic formation under high temperatures, thereby reinforcing the material. Conversely, at filler contents exceeding 30 wt%, the excessive filler disrupts the viscosity of the resin matrix, compromising the effective interaction between the resin and the fibers. Moreover, excessive filler results in local agglomeration within the system, which underperforms at elevated temperatures, leading to ceramics with suboptimal mechanical properties, as indicated by the reduced impact strength. Consequently, a filler content of 30 wt% has been determined as optimal. All subsequent tests on the BPR/MS/GF composite material will be conducted using these 30 wt% filler ratios.

Considering that ceramics formed by composites with MS filler exhibit uneven surfaces and fail to form effective ceramics at 600 ℃ and 800 ℃. Thus, glass powder is added as a flux to facilitate the formation of dense ceramics with adequate mechanical strength at high temperatures, also enhancing the material's mechanical strength and thermal resistance at 600 ℃ and 800 ℃. The optimal filler content is determined based on the impact strength of the material after treatment at 1000 ℃ for 30 min. As depicted in Fig. 3b, the residual rate of the composites after treatment at 1000 ℃ follows a similar trend to that of the BPR/MS/GF composites when varying the MSG filler content, reflecting the similar roles played by the fillers at high temperatures. It is observed that the impact strength of composites with MSG filler is generally higher than those with MS filler after treatment at 1000 ℃, indicating that the addition of glass frit enhances the mechanical performance of the ceramics formed at high temperatures. Given that ceramics containing 20 wt% MSG demonstrate superior mechanical properties, this concentration has been identified as the optimal filler content. Consequently, all subsequent tests on the BPR/MSG/GF composite material are conducted using these 20 wt% filler ratios.

3.3 Mechanical properties

As depicted in Figs. 4a༆4b, the mechanical properties of the BPR/MSG/GF composites follow a similar trend with temperature as the other two materials, exhibiting an initial increase followed by a decrease.

At room temperature, the impact strength and bending strength of the BPR/MSG/GF composites are the highest among the three materials, indicating that the incorporation of glass powder enhances the mechanical properties of the material. After treatment at 400 ℃, the impact strength and bending strength of the BPR/MSG/GF composites remain the highest among the three materials, with a significant improvement compared to the other two materials. This is attributed to the melting of glass powder at 400 ℃, forming a liquid phase that fills the pores within the loose char, thus maintaining a more intact residual structure and enhancing the mechanical properties of the material. After treatment at 600 ℃, both the impact and bending strengths of the BPR/MSG/GF composites significantly decrease but remain higher than those of the other materials. The liquid phase formed by the melting glass powder at 600 ℃ bridges other fillers and pyrolysis products of the material, enabling it to maintain relative integrity without delamination, thus the mechanical properties of the MSG-filled material treated at 600 ℃ are better than those of the other two materials. However, due to the absence of a eutectic reaction forming a ceramic layer at this temperature, severe resin pyrolysis occurs, leading to still poor mechanical properties. At 800 ℃ and 1000 ℃, the impact strength of the BPR/MSG/GF composites is noticeably higher than that of the other two materials, due to the eutectic reaction between the glass powder and the ceramic fillers, resulting in a dense and hard ceramic layer that significantly increases the material's hardness. At 1000 ℃, the more complete ceramic layer formation results in the highest impact strength. However, the brittleness of the ceramic layer still leads to relatively poor mechanical properties.

Comparative analysis reveals that BPR/MSG/GF composites exhibit superior mechanical properties, with impact and flexural strengths exceeding those of other materials under high temperatures. Wagner et al.[33], have demonstrated in their studies on GF-reinforced epoxy composites that these materials possess excellent impact resistance and are suitable for aerospace composite applications. Although BPR/MSG/GF composites have outstanding impact resistance, the brittleness of the ceramic layer at high temperatures may limit their practical applications.

3.4 Thermal properties

3.4.1 Thermodynamic stability

To investigate the thermal insulation properties of the composites, a butane flame was employed to incinerate the materials, with the flame temperature reaching up to 1000 ℃.

During combustion, the temperature on the reverse side of the materials was monitored in real time using an infrared thermometer, and the peak temperature recorded. As illustrated in Fig. 5a, after exposure to the butane flame, the BPR/GF composites failed to retain its original shape, undergoing significant bending. This deformation can be attributed to the boron-modified PR forming a porous char at high temperatures, which fails to provide structural support. Furthermore, the char does not effectively protect the GFs at high temperatures, leading to their softening and subsequent bending of the material. Post-burn, the material's surface was covered with a uniform layer of black char. The peak temperature on the reverse side of the material during the ablation process was 737.5 ℃. In contrast, the BPR/MS/GF composites maintained their original shape without significant deformation after exposure to the butane flame. This stability is due to the formation of an irregular ceramic layer from mica and SiO₂ on the material's surface, which protects the GFs allowing them to continue supporting the material. The material surface after flame ablation showed chunky residues, likely due to the unevenly distributed ceramic layer. The maximum temperature on the reverse side during the ablation was 653.7 ℃, lower than that of the BPR/GF composites, indicating that the uneven ceramic layer provided some degree of thermal insulation. BPR/MSG/GF composites displayed no significant deformation after exposure to the butane flame. This resilience is attributed to the rapid melting of glass powder at high temperatures, forming a liquid phase that, along with the pyrolytic products, creates a ceramic matrix that protects the composites at elevated temperatures. The added fillers play a role in supporting the structural integrity of the material, corroborating the microstructural appearance post-exposure to 1000 ℃. Additionally, after the butane flame ablation, the surface of BPR/MSG/GF composites showed the formation of a small amount of white ceramic. The maximum temperature on the reverse side during the ablation process was 646.7 ℃, the lowest among all samples, indicating that the formed ceramic provides effective thermal insulation. Figures 5b༆5c respectively depict the macroscopic photographs of the composites at various temperatures and the linear shrinkage rates after thermal treatment at different temperatures for 30 min. The BPR/GF composites showed no apparent deformation post-treatment at 400 ℃ and 600 ℃. However, significant deformations were observed at 800 ℃ and 1000 ℃ due to severe thermo-oxidative degradation of boron-modified PR at temperatures exceeding 800 ℃, resulting in a loosely structured char incapable of supporting the material structure. Furthermore, the GFs also experienced partial melting, diminishing their supporting function and leading to dimensional shrinkage of the samples. Additionally, the surface of the BPR/GF composites turned black post-400 ℃ treatment, indicative of partial thermal decomposition of the boron-modified PR generating a black char. Post-600 ℃ treatment, the BPR/GF composites appeared slightly whiter with delamination and surface black powder due to further decomposition of the resin at 600 ℃, leading to loose char formation, poor adhesion with the fibers, and eventual detachment. Moreover, the decomposition of resin generated low molecular weight gases, increasing inter-fiber pressure and causing fiber delamination. At 800 ℃, the BPR/GF composites turned white without delamination and retained certain hardness as GFs partially decomposed and melted, bonding the resin matrix and un-melted GF cloth, thus maintaining a relatively intact residual structure. At 1000 ℃, the samples resembled those treated at 800 ℃, but with further shrinkage due to additional melting of the GFs. The BPR/MS/GF composites showed no notable deformation at 400 ℃, slight deformation at 600 ℃, and significant deformation at 800 ℃ and 1000 ℃, for reasons similar to those affecting BPR/GF composites. Additionally, the shrinkage rates of BPR/MS/GF composites at high temperatures were higher than those without fillers due to the increased system viscosity from the filler addition, which impaired the resin's ability to wet the GF cloth, exposing the fibers more readily to high temperatures, facilitating their softening and melting. The filler's melting point, exceeding 1000 ℃, hindered liquid phase formation and the development of a protective ceramic layer, thus not improving the shrinkage rate. BPR/MSG/GF composites exhibited no significant deformation at 400 ℃ and 600 ℃ but slight deformation at 800 ℃ and 1000 ℃. Compared to BPR/GF and BPR/MS/GF samples, the shrinkage rate of BPR/MSG/GF at 1000 ℃ was notably reduced, almost matching that at 800 ℃, due to the melting of the glass powder at 1000 ℃ forming a liquid phase that underwent a eutectic reaction with SiO₂ to form a ceramic layer, protecting the material at high temperatures and filling the gaps and pores created by resin thermal decomposition, thus maintaining the original shape of the composites. Moreover, the BPR/MSG/GF composites exhibited no delamination at 600 ℃, as the melted glass powder formed a liquid phase replacing the resin as the binding agent, maintaining the original shape of the composites. These observations underscore the critical role of glass powder in maintaining material integrity, both at lower temperatures and above 800 ℃.

The thermal conductivity of a material signifies its capability to transfer heat, higher thermal conductivity correlates with enhanced thermal performance. Materials with superior thermal conductivity can promptly transfer heat when subjected to heating, preventing localized overheating and rapid thermal decomposition[21]. As shown in Fig. 5d, the thermal conductivity of the BPR/GF composites is 0.286 W·m^-1·K^-1, indicating modest thermal conductivity. The BPR/MS/GF composites exhibits an increased thermal conductivity compared to the BPR/GF composites that is 0.435 W·m^-1·K^-1, primarily because polymer heat conduction relies on energy transfer between crystals, whereas inorganic fillers conduct heat through the random movement of free electrons, yielding higher thermal efficiency. The thermal conductivity of mica, significantly higher than that of the resin, forms a thermal conduction network when uniformly distributed within the resin, enhancing the thermal conductivity of the filler-enhanced composites compared to those without fillers. Upon addition of glass powder, the thermal conductivity of the BPR/MSG/GF composites shows a minor increase about reaching to 0.451 W·m^-1·K^-1, closely resembling that of the BPR/MS/GF composites. This is attributed to the higher thermal conductivity of glass powder compared to silica and resin, albeit the similarity in thermal conductivity between mica and glass powder means the increase is not substantial. Figure 5e displays the DTG (Derivative Thermogravimetric) curves for the three composite materials, providing insights into their thermal decomposition rates. These curves, obtained from the first derivative of the thermogravimetric analysis, reveal that the thermal decomposition rates for the BPR/GF and BPR/MS/GF composites are quite similar, with peaks occurring within the range of 500–550 ℃ before they gradually decline. However, the DTG curve for the BPR/MSG/GF composite stands out as it exhibits a more moderate peak, reaching its maximum around 590 ℃ but remaining significantly lower than the peaks of the BPR/GF and BPR/MS/GF composites. It is worth noting that while the BPR/MSG/GF composite does show a slightly elevated thermal decomposition rate between 350 ℃ and 400 ℃ compared to the other two materials, its overall rate of thermal decomposition is considerably lower.

The TGA curves of the three composite materials are illustrated in Fig. 5f. Initially, up to 450 ℃, the primary weight loss is due to the evaporation of residual small molecules, the reduction of residual moisture, and the decomposition of the borate structure. During the intermediate stage, between 450 ℃ and 650 ℃, a rapid weight loss is observed as a result of the decomposition of the boron-modified PR structure. This phase is characterized by the breaking of chemical bonds and the release of volatile small molecules, leading to a significant deterioration in the mechanical properties of the composites. In the final stage, from 650 ℃ to 800 ℃, the rate of weight loss stabilizes as the thermal decomposition of the resin is largely complete, with the process primarily involving the carbonization of the remaining PR. When compared to the BPR/GF composites, the BPR/MS/GF composites follow a similar three-stage thermal degradation process but exhibit a noticeably slower degradation rate and a higher residue yield. The BPR/MSG/GF composites also go through these three phases, yet they display the highest residue yield among the tested materials. Before reaching 400 ℃, the BPR/MSG/GF composites exhibit the slowest rate of thermal weight loss, suggesting that the melting of the glass powder at this temperature provides a protective effect to the material.

Table 1

TG data of BPR/GF, BPR/MS/GF and BPR/MSG/GF in the air
Samples	$\:{\text{T}}_{5\%}$/ ℃	$\:{\text{T}}_{10\%}$/ ℃	Weight (%)
BPR	499.33	582.43	87.14
BPR/MS/GF	508.49	607.17	88.56
BPR/MSG/GF	519.15	715.00	89.91

$\:{\text{T}}_{5\%}$ : the temperature at 5 wt% weight loss (defined as the initial degradation temperature).

$\:{\text{T}}_{10\%}$ : the temperature at 10 wt% weight loss (defined as the initial degradation temperature).

According to Table 1, the residue yield of the BPR/MSG/GF composites is the highest at 89.91%, and while the temperature at 10% weight loss (T_10%) is the highest, the temperature at 5% weight loss (T_5%) is comparatively lower, suggesting a faster rate of early-stage thermal degradation. Overall, however, the thermal stability of the BPR/MSG/GF composites remains the best among the tested materials, demonstrating that the addition of glass powder further enhances the thermal stability of the composites.

In the aerospace industry, the need for a resilient thermal protection system is paramount, particularly for withstanding the intense heat encountered during launch and the dramatic temperature shifts in space. To this end, BPR/MSG/GF composites serve as crucial insulation materials in aerospace equipment. These composites provide an effective shield for spacecraft, safeguarding them from the extreme heat encountered during re-entry into Earth's atmosphere.

3.4.2 Pyrolytic gas analysis

Figures 6a༆6b illustrate that the BPR/MSG/GF composite material experiences a significant reduction in the absorbance of CO₂ and CO following high-temperature calcination, when compared to the BPR/GF composites. This reduction suggests a lower emission level for the BPR/MSG/GF composites. An examination of the thermal decomposition gases for both composite materials at temperatures of 200 ℃, 400 ℃, 600 ℃, and 800 ℃, as depicted in Figs. 6c & 6d, reveals a pronounced absorption at 2360 cm^− 1 for CO₂, 2180 cm^− 1 for CO, and 3588 cm^− 1 for H₂O within the temperature range of 400 ℃ to 800 ℃. Furthermore, at 600 ℃ and 800 ℃, the BPR/MSG/GF composites display distinct absorption peaks at 1026 cm^− 1 and 722 cm^− 1. These peaks correspond to the stretching vibrations of C-O and the bending vibrations of C-H on aromatic rings, respectively, which are not observed in the BPR/GF composites.

A temperature-wise analysis, as depicted in Fig. 6e, reveals that both composite materials begin to emit CO₂ around 450 ℃. Notably, the BPR/GF composite exhibits a higher relative absorbance, indicating a greater emission rate. Figure 6f illustrates that the BPR material starts releasing CO at temperatures above 350 ℃, while the BPR/MSG/GF composite only begins to emit CO after reaching 520 ℃. Furthermore, the BPR/MSG/GF composite shows a significantly lower overall CO release in comparison to the BPR/GF composite. Figure 6g demonstrates that the BPR/GF composite starts emitting water vapor at 600 ℃. In contrast, the BPR/MSG/GF composite initiates water vapor emission at a lower temperature of 350 ℃, with slightly higher emission levels at the same temperature point. However, these levels decrease after 660 ℃. Beyond 750 ℃, there is an increase in CO₂ emissions for the BPR/MSG/GF composite, yet they remain lower than those of the BPR/GF composite at comparable temperatures. Figure 6h indicates that BPR/MSG/GF composites release more volatile compounds at 400 ℃ than BPR/GF composites, with the primary compounds being phenolic substances and ether substances.

Overall, both composite released CO₂, CO, and H₂O during the heating process. The BPR/MSG/GF composites generated more volatiles at high temperatures compared to the BPR/GF composite; conversely, the BPR/GF composite produced more CO₂ than the BPR/MSG/GF composite. The analysis of TG-IR spectra (Fig. 6a & 6b) reveals that the absorbance at 1026 cm^− 1 for the pyrolysis gases of both materials is significantly lower than that for CO₂, indicating that the minimal release of volatile substances does not impact the thermal resistance of the BPR/MSG/GF composite. Furthermore, according to Costa et al.[39], CO and CO₂ are the primary causes of carbon loss in phenolic resins. The BPR/GF composites exhibited higher emissions of CO₂ than the BPR/MSG/GF composites. By comparison, the BPR/MSG/GF composites showed less carbon loss and superior thermal resistance, which is closely related to the dense ceramic layer formed at high temperatures.

3.5 Ceramization Mechanism

To delve into the ceramic characteristics of the BPR/MSG/GF composite materials, a series of XRD analyses were performed on the individual fillers after they underwent high-temperature treatment. This approach allowed for a detailed examination of the crystalline phases present. Furthermore, the composite materials themselves were subjected to XRD and XPS analyses following treatment at a range of temperatures. These analyses provided insights into the chemical composition and the state of the elements within the composites. Additionally, the microstructures of the materials were scrutinized using SEM, offering a high-resolution view of their surface morphology and internal structure.

Figure 7a reveals that the principal components of mica powder are muscovite and quartz. The peak positions in the XRD patterns of mica remain unchanged after treatment at 1000 ℃ compared to those at room temperature, indicating that mica does not undergo thermal decomposition to form new crystalline phases at this temperature. The XRD pattern of glass powder shows only amorphous diffraction peaks typical of non-crystalline structures, appearing between 2θ = 20° to 40°. Similarly, the XRD pattern of SiO₂ features amorphous diffraction peaks between 2θ = 20° to 35°, and SiO₂ maintains its amorphous structure after treatment at 1000 ℃, suggesting no phase transformation occurs during the ceramicization process in the composites. Figure 7b presents the XRD patterns of the BPR/MSG/GF composites after treatment at various temperatures. The characteristic peaks of the composites remain similar across different temperatures and closely resemble those of mica powder, indicating that mica does not react with other fillers to form new crystalline phases during the ceramicization process. Furthermore, the characteristic peaks of muscovite (2θ = 22.68°, 28.48°, 38.40°, 44.32°, 56.72°) gradually weaken with increasing temperature, suggesting partial thermal decomposition of mica and its eutectic reaction with glass powder and SiO₂. Figure 7c shows the XRD pattern of the BPR/MSG/GF composites after treatment at 1000 ℃, where amorphous diffraction peaks (2θ = 20° to 40°) indicate the occurrence of a eutectic reaction between mica and glass powder, resulting in the formation of amorphous products. This is attributed to the presence of substantial amounts of metal oxides in the glass powder, which can melt and disperse in the matrix at high temperatures to react eutectically with other thermal decomposition products.

Figures 7d༆7e correspond to the ceramicization mechanism schematic of the BPR/MSG/GF composites at high temperatures and the XPS analysis of the surface of the BPR/MSG/GF after treatment at room temperature and under a butane flame torch, respectively. Figure 7e reveals that peak deconvolution of the B2s XPS spectrum of the material at room temperature reveals peaks with binding energies at approximately 129.1 eV, 130.0 eV, and 140.5 eV, corresponding to B-O-C, B-O-B, and unreacted B-OH structures, respectively. Post-butane flame exposure, the B-OH structure disappears, and the intensity of the B-O-C structure increases, indicating the formation of new B-O-C linkages through condensation reactions between Ph-OH and B-OH at high temperatures. This increases the cross-linking density of the composites, thereby enhancing its high-temperature resistance.

For the C1s spectrum, peak deconvolution at room temperature shows peaks at binding energies of 284.8 eV and 286.5 eV, corresponding to C-C and C-OH structures, respectively. Post-exposure, a peak at 285.8 eV suggests a transformation of carbon elements within the composites to SP³ hybridized inorganic carbon. Analysis of the Si2p XPS spectrum shows peaks at a binding energy of 103 eV for both room temperature and post-combustion samples, with no significant change in intensity, indicating that the silicon remains predominantly in the form of SiO₂ throughout the process.

Combining the results from XRD and XPS analyses, as the ceramization mechanism shown in Fig. 7d, it is evident that besides the combustion reactions occurring during the thermal decomposition of the coating, the interactions between the coating, fluxing agents, and fillers are eutectic reactions. Besides, considering the SEM images of the surface morphology of BPR/MSG/GF composites treated at various temperatures, as depicted in Fig. 7f, demonstrate specific changes. After treatment at 400 ℃, partial thermal decomposition of the resin is observed, leading to the exposure of fibers. Despite this, the resin still maintains a uniformly covered morphology, indicating that the decomposition is not severe. At 600 ℃, fibers are more exposed, but the formation of a liquid phase is evident, which bridges the exposed fibers and prevents delamination while maintaining the original shape of the material.

Upon increasing the temperature to 800 ℃, a substantial amount of liquid phase forms, interconnecting the fibers. Some pores are visible on the surface of the fibers, resulting from the temperature not being sufficiently high to form a complete ceramic; some fibers are still exposed to high temperatures and undergo melting. At 1000 ℃, the surface of the material displays a uniform and dense ceramic layer. The presence of small pores on the ceramic surface is due to the escape of small molecular gases produced by the thermal decomposition of boron-modified PR.

Therefore, the ceramicization mechanism of BPR/MSG/GF can be inferred to be based on a eutectic reaction. As the temperature increases, the coating undergoes thermal decomposition, and low-melting-point fluxes melt; with further temperature elevation, ceramic fillers gradually melt and interact with the residual carbon and low-melting-point fluxes produced by the decomposition of the coating, forming a eutectic phase. This eutectic mixture is dispersed within the liquid phase, eventually forming a dense ceramic layer. Simultaneously, the release of CO₂ and small molecular volatile substances leads to the formation of a porous structure in the ceramic layer.

In conclusion, a boron-modified PR with excellent heat resistance was developed through modification of PR with boric acid. To further enhance its heat resistance, mica and SiO₂ were added to the boron-modified PR to create a ceramic system, with GF cloth used as the reinforcing material to fabricate the BPR/MS/GF composites. Based on the impact strength of the composites treated at 1000 ℃, the optimum filler content was determined to be 30 wt%. The performance of BPR/MS/GF composites at high temperatures was similar to that of BPR/GF composites, but at 1000 ℃, the BPR/MS/GF composites formed an incomplete ceramic layer, enhancing the material’s insulation properties. The residual rate in the thermogravimetric analysis of BPR/MS/GF composites was 88.56%, indicating improved thermal stability. Considering the incomplete and poorly protective ceramic layer formed by mica and SiO₂, glass powder was added as a flux to enhance the completeness of the ceramic layer formed at high temperatures. Based on the impact strength after treatment at 1000 ℃, the optimal filler content was adjusted to 20 wt%. Compared to BPR/MS/GF composites, BPR/MSG/GF composites showed improved mechanical strength, reduced shrinkage, and better insulation properties at high temperatures, capable of forming a complete ceramic layer. This composites shows potential for application in batteries, automotive, and cabin surfaces, aiming to mitigate the damage caused by external forces and high temperatures to the substrate material. The residual rate in the thermogravimetric analysis was 89.91%, signifying enhanced thermal stability. TG-IR analysis of the combustion processes of BPR/MS/GF and BPR/MSG/GF composites revealed that the release of volatile flammable substances was significantly reduced in BPR/MSG/GF, proving that the addition of glass powder resulted in a denser ceramic layer, thereby further enhancing the heat resistance of the compositess. XRD tests confirmed that the ceramic layer primarily consists of reaction products formed by eutectic reactions between mica and other fillers.

Ethical approval

The authors declare that ethical approval is not applicable to the content of this submission.

Conflict of interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author Contribution

Yande Liu wrote the main manuscript text and Dawei Jiang reviewed the manuscript and Mahmoud M. Hessien, M.H.H. Mahmoud polished the article language and Miaojun Xu put forward the whole idea of the article and Zeinhom M. El-Bahy reviewed the article figure. All authors reviewed the manuscript.

Acknowledgment

The work was supported by the Undergraduate Training Programs for Innovations by NEFU [grant number S20222142666055] and the National Natural Science Foundation of China (52273066). The authors extend their appreciation to Taif University, Saudi Arabia for supporting this work through project number (TU-DSPP-2024-72).

Data availability

Datasets related to this article can be found in the corresponding reference.

Li W, Sun H, Wang GH, Sui WJ, Dai L, Si CL (2023) Lignin as a green and multifunctional alternative to phenol for resin synthesis. Green Chem 25:2241–2261. https://pubs.rsc.org/en/content/articlelanding/2023/gc/d2gc04319j
Joseph JK, Naiker V, Sreeram P, Mampulliyalil F, George Varghese PJ, Dhawale PV, Sasidharan SP, Thakur VK, Raghavan P (2024) Chap. 16 - PR: Preparation, structure, properties, and applications. In: Raghavan P, Sreekala MS, Ravindran L, Menon A (eds) Handbook of Thermosetting Foams. Aerogels, and Hydrogels, pp 383–420
Xu Y, Guo L, Zhang H, Zhai H, Ren H (2019) Research status, industrial application demand and prospects of PR. RSC Adv 9:28924–28935. http://dx.doi.org/10.1039/C9RA06487G
Cheng C, Zhang XG, Wang YX, Sun L, Li CX (2012) Phenylboronic acid-containing block copolymers: synthesis, self-assembly, and application for intracellular delivery of proteins. New J Chem 36:1413–1421. https://pubs.rsc.org/en/content/articlelanding/2012/nj/c2nj20997g
Li S, Chen FH, Zhang BX, Luo ZH, Li H, Zhao T (2016) Structure and improved thermal stability of PR containing silicon and boron elements. Polym Degrad Stabil 133:321–329. https://www.sciencedirect.com/science/article/pii/S0141391016302245?via%3Dihub
Xin Y, Niu ZQ, Shen S, Ma XY, Chen F, Wang LY, Chen BX, Wang CZ, Zhang CS, Hou X (2023) A novel B-Si-Zr hybridized ceramizable PR and the thermal insulation properties of its fiber-reinforced composites. Ceram Int 49:4919–4928. https://linkinghub.elsevier.com/retrieve/pii/S0272884222035878
Morgan AB, Gilman JW (2013) An overview of flame retardancy of polymeric materials: application, technology, and future directions. Fire Mater 37:259–279. https://onlinelibrary.wiley.com/doi/ 10.1002/fam.2128
Huang Z, Wu Y, Shi M, Li L, Deng Z (2024) A novel Ti3SiC2-CaB6 modified Al-coated carbon fiber/boron PR ceramizable composite (ACF/BPRC) with excellent long-term oxidative corrosion resistance and high temperature load-bearing capacity. Corros Sci 227:111796. https://www.sciencedirect.com/science/article/pii/S0010938X23008399
Deng Z, Shi M, Huang Z, Yu X, Wu Y, Yang X (2023) Oxidation resistance, ablation resistance and in situ ceramization mechanism of Al-coated carbon fiber/boron PR ceramizable composites modified with Ti3SiC2. Ceram Int 49:32490–32502. https://www.sciencedirect.com/science/article/pii/S0272884223021508
Deng Z, Yang X, Yu X, Huang Z, Zhu D, Shi M (2023) High temperature flexural strength, microstructure, phase evolution and anti-oxidation mechanism of Al-coated carbon fiber/boron PR ceramizable composite modified with TiB2 and B4C. Ceram Int 49:25003–25015. https://www.sciencedirect.com/science/article/pii/S0272884223012750
Du Y, Xia Y, Luo Z, Yuan W, Xu K, Wang Q, Zhou H, Guo Y, Li H, Zhao T (2021) An addition-curable hybrid PR containing silicon and boron with improved thermal stability. Polym Degrad Stabil 189:109599. https://www.sciencedirect.com/science/article/pii/S0141391021001191
Yun J, Chen LX, Zhao H, Zhang XF, Ye WL, Zhu DF (2019) Boric Acid as a Coupling Agent for Preparation of PR Containing Boron and Silicon with Enhanced Char Yield. Macromol Rapid Commun 40:7. https://onlinelibrary.wiley.com/doi/10.1002/marc.201800702
Wang SJ, Wang Y, Bian C, Zhong YH, Jing XL (2015) The thermal stability and pyrolysis mechanism of boron-containing PRs: The effect of phenyl borates on the char formation. Appl Surf Sci 331:519–529. https://linkinghub.elsevier.com/retrieve/pii/S0169433215000860
Xing XL, Zhang P, Zhao YH, Ma F, Zhang XT, Xue F, Wang SJ, Jing XL (2021) Pyrolysis mechanism of phenylboronic acid modified PR. Polym Degrad Stabil 191:10. https://linkinghub.elsevier.com/retrieve/pii/S0141391021001920
Deng Z, Wu Y, Shi M, Yang X, Huang Z (2023) Ablation behavior, microstructure, phase evolution and in situ ceramization mechanism of ZrC-LaB6 modified carbon fiber/PR ceramizable composite. Polym Degrad Stabil 218:110584. https://www.sciencedirect.com/science/article/pii/S0141391023003336
Clausi M, Zahid M, Shayganpour A, Bayer IS (2022) Polyimide foam composites with nano-boron nitride (BN) and silicon carbide (SiC) for latent heat storage. Adv Compos Hybrid Mater 5:798–812. https://link.springer.com/article/10.1007/s42114-022-00426-1
Liu F, Kong J, Luo CJ, Ye F, Luan XG, Tian N, Liu YS, Zhang H, Gu JW, Tang YS (2018) High temperature self-healing SiBCN ceramics derived from hyperbranched polyborosilazanes. Adv Compos Hybrid Mater 1:506–517. https://link.springer.com/article/ 10.1007/s42114-018-0044-3
Zhang H, Liang XB, Hu YL, Zhang P, Yang LW, He DY, Hua MY, Tong YG (2021) Correlation of C/C preform density and microstructure and mechanical properties of C/C-ZrC-based ultra-high-temperature ceramic matrix composites. Adv Compos Hybrid Mater 4:743–750. https://link.springer.com/article/ 10.1007/s42114-021-00295-0
Roy R, Das D, Rout PK (2022) A Review of Advanced Mullite Ceramics. Eng Sci 18:20–30. http://dx.doi.org/10.30919/es8d582
Ahmad S, Ali S, Salman M, Baluch AH (2021) A comparative study on the effect of carbon-based and ceramic additives on the properties of fiber reinforced polymer matrix composites for high temperature applications. Ceram Int 47:33956–33971. https://linkinghub.elsevier.com/retrieve/pii/S0272884221027607
Ma ZW, Zhang JZ, Maluk C, Yu YM, Seraji SM, Yu B, Wang H, Song PA (2022) A lava-inspired micro/nano-structured ceramifiable organic-inorganic hybrid fire-extinguishing coating. Matter 5:911–932. https://linkinghub.elsevier.com/retrieve/pii/S2590238521006342
Yang H, Li Q, Wang Z, Wu H, Wu Y, Cheng X (2022) Effect of Different Sintering Additives on the Microstructure, Phase Compositions and Mechanical Properties of Si3N4/SiC Ceramics. ES Mater Manuf 15:65–71. http://dx.doi.org/10.30919/esmm5f487
Agrawal N, Thakur OP, Singh AK (2021) Role of shape, size and concentration of filler particles on filler matrix interface: A mathematical analysis. Materials Today: Proceedings 44:890–894. https://www.sciencedirect.com/science/article/pii/S2214785320384303
Yu DK, Xue ZM, Mu TC (2021) Eutectics: formation, properties, and applications (vol 50, pg 8596, 2021). Chem Soc Rev 50:9345–9345. https://pubs.rsc.org/en/content/articlelanding/2021/cs/d1cs90065j
Guo JH, Gao W, Wang Y, Liang D, Li HJ, Zhang X (2017) Effect of glass frit with low softening temperature on the properties, microstructure and formation mechanism of polysiloxane elastomer-based ceramizable composites. Polym Degrad Stabil 136:71–79. https://www.sciencedirect.com/science/article/pii/S0141391016303913?via%3Dihub
Li ZX, Liang WJ, Shan YF, Wang XX, Yang K, Cui YY (2020) Study of flame-retarded silicone rubber with ceramifiable property. Fire Mater 44:487–496. https://onlinelibrary.wiley.com/doi/10.1002/fam.2802
Xu L, Shen J, Sun Q, Zhang J, Sheng J (2023) Effect of glass frits on ceramifiable properties of polyethylene composites. Fire Mater 47:874–883. https://onlinelibrary.wiley.com/doi/abs/10.1002/fam.3131
Shi L, Song G, Li P, Li X, Pan D, Huang Y, Ma L, Guo Z (2021) Enhancing interfacial performance of epoxy resin composites via in-situ nucleophilic addition polymerization modification of carbon fibers with hyperbranched polyimidazole. Composites Science and Technology 201. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85094320231&doi=10.1016%2fj.compscitech.2020.108522&partnerID=40&md5=7f5e4dd44bb65db6e37215beac2e0802
Wu C, Cao S, Zhao YJ, Qi H, Liu X, Liu G, Guo J, Li HN (2021) Preheating assisted wire EDM of semi-conductive CFRPs: Principle and anisotropy. Journal of Materials Processing Technology 288. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091962473&doi=10.1016%2fj.jmatprotec.2020.116915&partnerID=40&md5=36a3e5aefa743b11fb5bcd3bb6e6e015
Forintos N, Czigany T (2019) Multifunctional application of carbon fiber reinforced polymer composites: Electrical properties of the reinforcing carbon fibers – A short review. Composites Part B: Engineering 162:331–343. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056222363&doi=10.1016%2fj.compositesb.2018.10.098&partnerID=40&md5=a50a9c7bca0145406c3036d44480bd25
Yu J, Cui Z, Lu J, Zhao J, Zhang Y, Fan G, Liu S, He Y, Yu Y, Qi D (2021) Integrated hierarchical macrostructures of flexible basalt fiber composites with tunable electromagnetic interference (EMI) shielding and rapid electrothermal response. Composites Part B: Engineering 224. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85111676641&doi=10.1016%2fj.compositesb.2021.109193&partnerID=40&md5=132d413d274ed5adf91bd855003e6bc0
Kumar S, Singh KK (2020) Tribological behaviour of fibre-reinforced thermoset polymer composites: A review. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234:1439–1449. https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088393046&doi=10.1177%2f1464420720941554&partnerID=40&md5=740e977a42fd03193f0a66fe88419fc5
Wagner T, Heimbs S, Franke F, Burger U, Middendorf P (2018) Experimental and numerical assessment of aerospace grade composites based on high-velocity impact experiments. Compos Struct 204:142–152. https://www.sciencedirect.com/science/article/pii/S0263822318306779
Kazi AM, Ramasastry DVA, Waddar S (2022) Characterization of interwoven roselle/sisal fiber reinforced epoxy composites. Polym Compos 43:1421–1428. https://4spepublications.onlinelibrary.wiley.com/doi/ 10.1002/pc.26462
Da-Peng Z, Hong F (2008) Mechanical and high-temperature properties of glass fibers reinforced phenolic composites. J Reinf Plast Compos 27:1449–1460. https://journals.sagepub.com/doi/10.1177/0731684407086613
Choe J, Kim M, Kim J, Lee DG (2016) A microwave foaming method for fabricating glass fiber reinforced phenolic foam. Compos Struct 152:239–246. https://linkinghub.elsevier.com/retrieve/pii/S0263822316305797
Zhou JT, Yao ZJ, Chen YX, Wei DB, Wu YB (2013) Thermomechanical analyses of phenolic foam reinforced with glass fiber mat. Mater Des 51:131–135. https://www.sciencedirect.com/science/article/pii/S0261306913003452?via%3Dihub
Kim M, Choe J, Lee DG (2016) Development of the fire retardant glass fabric/carbonized phenolic composite. Compos Struct 148:191–197. https://linkinghub.elsevier.com/retrieve/pii/S0263822316302331
Costa L, di Montelera LR, Camino G, Weil ED, Pearce EM (1997) Structure-charring relationship in phenol-formaldehyde type resins. Polym Degrad Stabil 56:23–35. https://www.sciencedirect.com/science/article/pii/S0141391096001711

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Enhanced Thermal and Mechanical Properties of Boron-Modified Phenolic Resin Composites in a Multifiller System: Potential Applications in Aerospace Materials

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Abstract

Figures

1. Introduction

2. Experimental Section

2.1. Materials

2.2 Synthesis of BPR

2.3 Synthesis of BPR/MS/GF Composites

2.4 Synthesis of BPR/MSG/GF Composites

2.5 Characterization

2.5.1 Structural characterization of BPR

2.5.2 Physical properties analysis of composites

2.5.3 Thermal stability of composites

2.5.4 Analysis of ceramic properties of composites

3. Results and discussion

3.1 Structural analysis of BPR

3.2 Determination of the optimal addition ratio of BPR/MS/GF Composites and BPR/MSG/GF Composites

3.3 Mechanical properties

3.4 Thermal properties

3.4.1 Thermodynamic stability

3.4.2 Pyrolytic gas analysis

3.5 Ceramization Mechanism

4. Conclusion

Declarations

Author Contribution

Acknowledgment

Data availability

References

Additional Declarations

Supplementary Files

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