Carbon Resin Research Articles

Acidity regulation of boron phosphate flame retardant and its catalyzing carbonization mechanism in epoxy resin

Boron phosphates (BPs) with different acidities were prepared by regulating the calcination temperatures for the reaction products of boric acid and phosphoric acid. The crystal structure, morphology, surface acidity, and thermal stability were characterized by X-ray diffraction, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), chemical absorbed apparatus, and thermogravimetric analysis (TG). The effects of BPs on the combustion behavior and catalyzing the carbonization of bisphenol-A epoxy resin (EP) were investigated by the limiting oxygen index (LOI) and cone calorimetry test. Upon loading 5 mass% BP prepared at 300 °C, the LOI value of the EP/BP composites increased to 29.6%, and moreover, the peak heat release rate and average specific extinction area decreased by 43 and 25%, respectively. A possible catalyzing carbonization mechanism was explored by TG coupled with Fourier transform infrared spectroscopy (TG–FTIR), TG, FTIR, SEM, Raman spectroscopy (Raman), and XPS. The results demonstrated that BP catalyzed EP to degrade at relatively low temperature, and the yield, compactness, and graphitization degree of the char residue were obviously enhanced with an increase in the ratio of Bronsted and Lewis acid sites (B/L value) and the total surface acid sites on the BP surface. Therefore, the catalyzing carbonization flame retardancy of the EP/BP composites can be improved through regulating the surface acidity of BP.

Study of resin flow in carbon fiber reinforced polymer composites by means of pressure sensors

This paper presents an evaluation of resin flow in carbon fiber reinforced polymer by means of small embedded pressure sensors. High-quality carbon fiber reinforced polymer parts require entire impregnation of fibers with resin before resin curing starts. Small piezo-resistive pressure sensors are used to measure the vacuum hold and to track resin flow and pressure elevation inside the composite part. The sensors are placed at different locations in the fiber stacks. Real-time pressure changes are obtained inside the laminate during infusion. To reduce the size of the embedded sensing element, the sensor dies are flip-chipped on a thin printed circuit board. The two component thermoset resin (RIM 035 c) and uni-directional carbon fiber with the alignment of 30° are used in a complex-shaped mold. The result shows that the flip-chipped piezo-resistive pressure sensors can be used in conductive fibers to monitor resin arrival and pressure development in vacuum assisted resin transfer molding infusion processes. The sensors are supplied by a constant current source to compensate the sensitivity reduction if the temperature changes in the curing process.

Boron and nitrogen co-doped porous carbon with a high concentration of boron and its superior capacitive behavior

In this work, boron and nitrogen co-doped hierarchical porous carbon (BN-HPC) with a relatively high contents of boron (3.97 wt%) and nitrogen (12.10 wt%) is synthesized by a method combined with template process and carbonization of hierarchical porous resin using melamine and boric acid as nitrogen and boron sources, respectively. The co-doping method achieves a high boron doping level (8 times of that of single boron doped sample) which is of great significance in increasing the doping efficiency of boron. The hierarchical porosity, structure and surface chemical properties are studied in detail via various means, such as Transmission Electron Microscopy, N2 sorption, X-ray diffraction, X-ray photoelectron spectroscopy and elemental analysis, etc. Owing to the synergistic effect of hierarchical porosity and heteroatoms doping, BN-HPC exhibits greatly improved electrochemical capacitive performance of 304 F g−1 at a current density of 0.1 A g−1 and good rate capability (189 F g−1 remained at a current density of 10 A g−1). The strategy of synthesis is facile and very effective.

Mechanical Property, Oxidation and Ablation Resistance of C/C–ZrB2–ZrC–SiC Composite Fabricated by Polymer Infiltration and Pyrolysis with Preform of Cf/ZrB2

C/C–ZrB2–ZrC–SiC composites were fabricated by polymer infiltration and pyrolysis (PIP) with a preform of Cf/ZrB2. The carbon fibers and the resin carbon were coated with ceramic layer after PIP in the composites. The composite presents a pseudo-plastic fracture due to deflection of cracks and pullout of fibers. The composite has a higher bending strength by this method in comparison with the conventional PIP process due to fewer heat treatment cycles. The static oxidation test shows that the mass loss of the composites is no more than 1% after 20 min oxidation at 1100 °C. The “core–shell” structure between ZrC–SiC ceramic and other phases plays a positive role in preventing the inward diffusion of oxygen. The ablation resistance of the C/C–ZrB2–ZrC–SiC composite samples was tested using a plasma generator. After ablation for 120 s, the mass and linear ablation rates of the composites are 4.65 mg cm−2 s−1 and 2.46 µm s−1, respectively. The short carbon layer shows a better ablation resistance than the nonwoven carbon fabric layer after the ceramic coating is peeled off because of its higher ceramic content.

Controlled Synthesis of Ordered Mesoporous Carbon-Cobalt Oxide Nanocomposites with Large Mesopores and Graphitic Walls

Ordered mesoporous carbon (OMC)-metal oxide composites have attracted great interest due to their combination of high surface area, uniform pores, good conductivity of mesoporous carbon, and excellent photo-, electro- and chemical sensing properties of metal oxides. Herein, OMC-metal oxide composites with large mesopores and monodispersed CoOx nanoparticles were synthesized via a controllable multicomponent cooperative coassembly of ultrahigh-molecular-weight poly(ethylene oxide)-block-polystyrene (PEO-b-PS) copolymers, resol (soluble phenoic resin carbon precursor), and cobalt nitrate (cobalt oxide precursor). The obtained nanocomposites possess a face-centered cubic (fcc) mesoporous structure, large pore size (13.4–16.0 nm), high surface area (394–483 m2/g), large pore volume (0.41–0.48 cm3/g), and uniform CoOx nanoparticles with tunable diameters (6.4–16.7 nm). The long chain length of amphiphilic PEO-b-PS template molecules contributes to large mesopores and thick pore walls that allow a controllable ...

리튬이차전지용 Hollow Silicon/Carbon 음극소재의 전기화학적 성능

이차전지 음극소재인 실리콘의 부피팽창을 개선하기 위하여 hollow silicon/carbon (H-Si/C) 복합체의 특성을 조사하였다. <TEX>$St{\ddot{o}}ber$</TEX>법을 통해 합성한 <TEX>$SiO_2$</TEX>에 <TEX>$NaBH_4$</TEX>를 첨가해 hollow 형태의 <TEX>$SiO_2\;(H-SiO_2)$</TEX>를 제조한 후, 마그네슘 열 환원 반응과 phenolic 수지(resin)를 첨가한 후 탄화과정을 거쳐서 H-Si/C 복합체를 합성하였다. 제조된 H-Si/C 합성물은 XRD, SEM, BET, EDX, TGA를 통해 특성을 분석하였다. 음극소재의 용량과 사이클 안정성을 향상시키기 위해서, <TEX>$NaBH_4$</TEX> 첨가량에 따라 합성된 H-Si/C 복합체의 전기화학적 특성을 충방전, 사이클, 순환전압전류, 임피던스 테스트를 통해 조사하였다. H-Si/C 음극활물질과 <TEX>$LiPF_6$</TEX> (EC : DMC : EMC = 1 : 1 : 1 vol%) 전해액을 사용하여 제조한 코인셀은 <TEX>$SiO_2:NaBH_4=1:1$</TEX>일 때 1459 mAh/g의 향상된 용량을 나타내었으며, 사이클 성능 또한 두 번째 사이클 이후 40번째 사이클까지 매우 우수한 안정성을 나타냄을 확인하였다. Hollow silicon/carbon (H-Si/C) composites as anode materials for lithium ion batteries were investigated to overcome the large volume expansion. H-Si/C composites were prepared as follows; hollow <TEX>$SiO_2\;(H-SiO_2)$</TEX> was prepared by adding <TEX>$NaBH_4$</TEX> to <TEX>$SiO_2$</TEX> synthesized using <TEX>$st{\ddot{o}}ber$</TEX> method followed by magnesiothermic reduction and carbonization of phenolic resin. The H-Si/C composites were analyzed by XRD, SEM, BET and EDX. To improve the capacity and cycle performance, the electrochemical characteristics of H-Si/C composites synthesized with various <TEX>$NaBH_4$</TEX> contents were investigated by charge/discharge, cycle, cyclic voltammetry and impedance tests. The coin cell using H-Si/C composite (<TEX>$SiO_2:NaBH_4=1:1$</TEX> in weight) in the electrolyte of <TEX>$LiPF_6$</TEX> dissolved in organic solvents (EC : DMC : EMC = 1 : 1 : 1 vol%) has better capacity (1459 mAh/g) than those of other composition coin cells. It is found that the coin cell (<TEX>$SiO_2:NaBH_4=1:1$</TEX> in weight) has an excellent capacity retention from 2nd cycle to 40th cycle.

Experimental investigation and numerical modelling of the fire performance for epoxy resin carbon fibre composites of variable thicknesses

SummaryThis paper applies a unique integrated approach to determine the flammability properties of a composite material (epoxy with carbon fibre) and compares its fire behaviour at two different thicknesses (2.1 and 4.2 mm) by performing small scale (thermo‐gravimetric analysis (TGA)/Fourier transform infrared radiation) and meso‐scale tests (cone calorimeter). For small‐scale tests, experiments were conducted in nitrogen using TGA coupled to gas analysis by Fourier transform infrared radiation. These results allow the determination of thermal stability, main degradation temperature and main gaseous emissions released during the thermal degradation. For meso‐scale tests, experiments were carried out using a cone calorimeter with sample dimensions of 100 × 100 mm at five heat fluxes (30, 40, 50, 60 and 70 kW/m2). The results show that the ignition time increases with an increase in the thickness of the material. Relative hazard classification of the fire performance of the current composites has also been compared with other materials using parameters obtained elsewhere. In addition, the effective ignition, thermal and pyrolysis properties obtained from the ignition and mass loss rate experiments for the 4.2‐mm thick samples were used in a numerical model for pyrolysis to predict well ignition times, back‐surface temperatures and mass pyrolysis rates for all heat fluxes as well as for the 2.1‐mm thick samples. Note that the ignition temperature obtained in the cone agrees with the main degradation temperature in the TGA. The flammability properties deduced here can be used to predict the heat release rate for real fire situations using CFD modelling. Copyright © 2016 John Wiley &amp; Sons, Ltd.

Electrochemical Characteristics of Silicon/Carbon Anode Composite with Various Binders and Additives

In recent years, lithium ion battery has been widely used on portable electronic devices and electric/hybrid vehicles because of its high energy density and cycling stability. As an anode material for the lithium ion battery, Silicon(Si) is getting attention for its high theoretical specific capacity (about 4200mAh/g) and its proper potential range for lithium insertion and extraction. However, Si has properties that could be obstacles for its practical use as the lithium ion battery anode. Si not only has low intrinsic electric conductivity but also undergoes severe volume changes during the lithium ion insertion/extraction process which results in pulverization of the electrode materials, causing the capacity to fade. To overcome these problems and enhance the electric conductivity, we synthesized Silicon/Carbon composites as an anode material. Si/C composites were prepared by two step method, including magnesiothermic reduction of SBA-15(Santa Barbara Amorphous material No. 15) and carbonization of phenol resin. The electrochemical performances of Si/Carbon composites were investigated to find the effect of binders and an electrolyte additives by charge/discharge, cyclic voltammetry and impedance tests. The anode electrode of Si/C composite with PAA binder appeared better capacity(1,899 mAh/g) and the capacity retention ratio(92%) than that of other composition coin cells during 40 cycles. Also, Vinylene carbonate(VC) was tested as an electrolyte additive. The influence of this additive on the behavior of Si/Carbon anodes was very positive(3,049 mAh/g), since the VC additive is formed passivation films on Si/C surfaces and suppresses irreversible changes in electrolyte solution .

Development of the fire retardant glass fabric/carbonized phenolic composite

Because fiber reinforced polymeric composite materials have the advantages of high specific strength and stiffness, their potential for replacing concrete, aluminum and steel. However, the poor fire resistance of fiber reinforced polymeric composite materials is one of the obstacles for their applications.In this study, a fire retardant glass fabric/carbonized phenolic composite was developed using the carbonization of the phenolic resin. Although the glass fiber is not combustible, it melts at approximately 800°C on exposure to fire, whereas the phenolic resin has good fire resistance with minimum smoke levels, excellent dimensional stability and thermal strength. Moreover, the phenolic resin is carbonized at high temperature (above 500°C), which prevents the spread of flames. However, shrinkage during the carbonization process weakens its strength and stiffness.To improve the pristine- and post-fire mechanical properties of the glass fabric/phenolic composite, flame and silane treatments were applied to the glass fabrics. The carbonization and impregnation of the phenolic resin matrix of the composite was repeated several times to develop the glass fabric/carbonized phenolic composite, from which the post-fire tensile strength and the carbonized phenol matrix ratio were measured with respect to the number of carbonization processes.

Polyester resin and carbon nanotubes based nanocomposite as new-generation coating to prevent biofilm formation

ABSTRACTIn this article, we have developed protective nanocomposite coatings using unsaturated polyester resin and multiwalled carbon nanotubes showing antimicrobial activity and mechanical durability. Carbon nanotubes retain the mechanical resilience of polyester resin in the nanocomposite, improve its hydrophobic character, and increase the adhesion features of the coating, preventing its stiffness from decreasing due to water absorption or exposure to UV rays. Nanocomposite coating exhibits an appreciable antimicrobial property and a lower level of toxicity compared to pure resin. All these features make this material a good candidate for its use in the field of anti-biofilm coatings.

Fabrication and microstructure of 3D Cf /ZrC-SiC composites: through RMI method with ZrO2 powders as pore-making agent

3D Cf/ZrC–SiC composites were prepared by a combination process of slurry infiltration and reactive melt infiltration. ZrO2 powders and ZrSi2 alloy, both of which reacted with amorphous carbon, were used as pore-making agent and infiltrator, respectively. After carbothermal reduction at 1650°C, X-ray diffraction analysis revealed that ZrO2 powders were completely converted into ZrC by reacting with amorphous carbon, and an in-situ formed submicron porous configuration was observed at the areas containing ZrO2. Results showed that the matrix in composites mainly consisted of SiC, ZrC and a small quantity of residual metal. SEM and TEM images revealed the formation of ZrC or SiC intergranular particles in the matrix and the characteristic around the residual resin carbon. The composites had a bending strength of 94.89±16.7MPa, fracture toughness of 11.0±0.98MPam1/2, bulk density of 3.36±0.01g/cm3, and open porosity of 4.64±0.40%. The formation mechanisms of ZrC–SiC dual matrix and intrabundles׳ structure were discussed in the article.

Polycondensation and carbonization of phenolic resin on structured nano/chiral silicas: reactions, morphologies and properties.

In this research, we extended a bioinspired and templated synthesis way for SiO2 to carbonaceous materials, with the success in morphology control and inducing chirality at the nano-scale. The biopolymer-analogue polyamine, i.e., polyethyleneimine (PEI) was employed as a catalytic template for SiO2 formation, and the as-formed PEI@SiO2 hybrids, which combine the rigidity of SiO2 and the chemical activity of PEI, were further used as hard-templates and basic catalysts for the deposition of phenolic resin on PEI@SiO2 under mild conditions. Through further carbonization and etching SiO2, SiO2/carbon composites and carbonaceous materials were produced, respectively. After characterization of these products by SEM, TEM, XPS, Raman spectroscopy, FT-IR, and TG-DTA, it was demonstrated that the morphologies were well transmitted in these successive steps. By taking advantage of the diverse modulation ways on the morphologies and structures of initial PEI templates, it is easy to achieve SiO2/carbon and carbonaceous products with different morphologies, including nanofibrils, nanobelts, and nanotubes. Moreover, this process could also fulfill a steady chirality transmission. When PEI complexed with chiral tartaric acid, the resulting chiral complex could function both as a template and chirality source, and finally chiral nanostructured carbonaceous products were obtained.

Humidity Tolerant Organic Vapor Detection Using a Superhydrophobic Quartz Crystal Microbalance

The organic vapor sensitivity of a quartz crystal microbalance (QCM) with an epoxy resin–carbon soot coating designed to be tolerant to humidity is reported. This is achieved using nonengulfed, but attached, hydrophobic carbon soot nanoparticles, coated in an irregular surface topography composed of islands and cavities. The root mean square roughness ( $R_{\mathrm {{rms}}}$ ) of 130 nm, together with the hydrophobic soot, convert the epoxy surface to a superhydrophobic (SH) one with high static contact angle ( $\sim 151^{\circ }$ ) and low contact angle hysteresis ( $\sim 1.1^{\circ }$ ). The frequency shift of the SH QCM at 100% relative humidity is $\sim 7$ times lower compared with an uncoated device, and thus indicating low water vapor adsorption due to superhydrophobicity. In addition, the SH QCM shows between three and six times higher gas sensitivity and lower detection limit compared with the conventional polymer coated QCMs. These results correlate well with the $R_{\mathrm {{rms}}}$ and surface topography of the coating, which ensure enhanced sensing area. Furthermore, the sensor demonstrates reproducibility, reversibility, and fast response-recovery time ( $\sim 10$ s) to ethanol, methanol, and isopropanol vapor. These experiments reveal that superhydrophobicity increases the organic vapor sorption at the expense of water vapor sorption, and thus allowing operation of the QCM gas sensors in an uncontrolled humidity environment.

메조기공 Silicon/Carbon/CNF 음극소재 제조 및 전기화학적 특성

Si/C/CNF composites as anode materials for lithium-ion batteries were examined to improve the capacity and cycle performance. Si/C/CNF composites were prepared by the fabrication process including the synthesis and magnesiothermic reduction of SBA-15 to obtain Si/MgO by ball milling and the carbonization of phenol resin with CNF and HCl etching. Prepared Si/C/CNF composites were then analysed by BET, XRD, FE-SEM and TGA. Among SBA-15 samples synthesized at reaction temperatures between 50 and , the SBA-15 at showed the largest specific surface area. Also the electrochemical performances of Si/C/CNF composites as an anode electrode were investigated by constant current charge/discharge test, cyclic voltammetry and impedance tests in the electrolyte of LiPF6 dissolved in mixed organic solvents (EC : DMC : EMC

Electrochemical Characteristics of Si/C/CNT Composites for Anode Material of Lithium Ion Battery

In recent years, lithium ion battery has been widely used on portable electronic devices and electric/hybrid vehicles because of its high energy density and cycling stability. As an anode material for the lithium ion battery, Silicon(Si) is getting attention for its high theoretical specific capacity (about 4200mAh/g) and its proper potential range for lithium insertion and extraction. However, Si has properties that could be obstacles for its practical use as the lithium ion battery anode. Si not only has a low intrinsic electric conductivity but also undergoes severe volume changes during the lithium ion insertion/extraction process which results in pulverization of the electrode materials, causing the capacity to fade. To overcome these problems and enhance the electric conductivity, we synthesized Silicon/Carbon/CNT composites as an anode material. Si/C/CNT composites were prepared by the fabrication processes including the synthesis of SBA-15, magnesiothermic reduction of SBA-15 to obtain Si/MgO by ball milling, carbonization of phenolic resin with CNT and HCl etching. The prepared Si/C/CNT composites were analysed by BET, XRD, FE-SEM and TGA. Among the SBA-15 samples synthesized with reaction temperatures between 50°C and 70°C, the SBA-15 of 60°C showed the largest specific surface area. Also the electrochemical performances of Si/C/CNT composites as the anode electrode were investigated by constant current charge/discharge test, cyclic voltammetry and leakage tests in the electrolyte of LiPF6 dissolved in organic solvents(EC:DMC:EMC=1:1:1 vol%). The coin cell using Si/C/CNT composite(Si:CNT=97 :3 in weight) has better capacity(1,440 mAh/g) than that of other composition coin cells. Also, it is found that Si/C/CNT composite(Si:CNT=97:3 in weight) electrode shows improved cycling performance and electric conductivity.

Adsorption characteristics of polycyclic aromatic hydrocarbons from non-aqueous media using activated carbon derived from phenol formaldehyde resin: kinetics and thermodynamic study.

Porous carbons were prepared by carbonization and activation of phenol formaldehyde resin by gasification with CO2 at 900°C. Prepared activated carbon from phenol formaldehyde was characterized by measuring thermogravimetry (TG), differential thermal analysis (DTA), pH, surface area, porosity, and pore size distribution. The specific surface area (SSA) of these carbons ranges from 562 to 1904m2/g, while their point of zero charge (pHPZC) varies from 2.6 to 8.8. The ability of the prepared activated carbon by gasification with CO2 at 900°C from phenol formaldehyde resin (PFAC) to remove a series of polycyclic aromatic hydrocarbons (PAHs), e.g., naphthalene, fluorene, phenanthrene, pyrene, and fluoranthene, from mixtures of organic solvents with different polarities and chemical structures was tested. The adsorption capacity increases with the increasing the SSA and pHPZC of the carbons, confirming the roles of dispersive interactions. The kinetics and thermodynamics of the adsorption of phenanthrene as a model compound of PAH on PFAC in the organic solvent were studied. The adsorption capacity became notably greater with an increase in contact time and initial phenanthrene concentration.

Flake structured SnSbCo/MCMB/C composite as high performance anodes for lithium ion battery

SnSbCo/MCMB/C composite with flake structure were prepared by stepwise synthesis method. Firstly, SnSbCo nanoparticles were fabricated by co-precipitation, and then nanosized SnSbCo alloy were embedded in mesocarbon microbeads (MCMB) by ball-milling to synthesize primitive SnSbCo/MCMB hybrids, followed by carbonization of phenolic resin to produce an outer layer of carbon coating. The crystal structure, morphology and electrochemical properties of the SnSbCo/MCMB/C composite were evaluated by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and galvanostatical cycling tests. Compared with bare SnSbCo alloy and SnSbCo/MCMB hybrids, the efficiently enhanced electrochemical performance of SnSbCo/MCMB/C composite were mainly ascribed to the improved electron conductivity and volume buffering effect provided by the amorphous carbon coating. The resultant SnSbCo/MCMB/C composite delivered an initial discharge capacity of 848 mAh g−1 under 100 mA g−1, with a good capacity retention of 85.6% after 70 cycles. The composite also exhibited excellent rate capability of 603 mAh g−1 and 405 mAh g−1 at the current density of 200 mA g−1 and 1000 mA g−1, respectively.

Ablation mechanism of C/C–ZrB2–ZrC–SiC composite fabricated by polymer infiltration and pyrolysis with preform of Cf/ZrB2

C/C–ZrB2–ZrC–SiC composites were fabricated by polymer infiltration and pyrolysis (PIP) with a preform of Cf/ZrB2. The ZrB2 powders were sprayed onto fabric layer by layer before the fabric is needled. After introduction of resin carbon and ZrC–SiC into the preform, a ceramic coating on the matrix and fibres was formed in the composites. The plasma ablation test indicates that the composites possess a good ablation resistance after ablation for 180s and 240s. The SiO2–ZrO2 barrier layer, high temperature Zr–Si–O glass layer and heat dissipation all contribute to the good ablation resistance of the composites.

Material Characteristics of Fabricated Resin Carbon Nanotube Reinforced and Resin Glass Fiber Carbon Nanotube Reinforced Composites

Due to high mechanical strength, carbon nanotubes (CNTs) are being considered as nanoscale fibres to enhance the performance of polymer composite materials. The two different types of composite reinforced polymers are fabricated with correct proportions with CNTs for better mechanical efficiency. Two types of CNT-based composites are resin carbon nanotube reinforced and resin glass fiber carbon nanotube reinforced. The reinforced CNT composite polymers are SEM, EDAX and XRD analysed for unified structural stability.

Flexural properties of polyethylene, glass and carbon fiber-reinforced resin composites for prosthetic frameworks

Objective. High flexural properties are needed for fixed partial denture or implant prosthesis to resist susceptibility to failures caused by occlusal overload. The aim of this investigation was to clarify the effects of four different kinds of fibers on the flexural properties of fiber-reinforced composites. Materials and methods. Polyethylene fiber, glass fiber and two types of carbon fibers were used for reinforcement. Seven groups of specimens, 2 × 2 × 25 mm, were prepared (n = 10 per group). Four groups of resin composite specimens were reinforced with polyethylene, glass or one type of carbon fiber. The remaining three groups served as controls, with each group comprising one brand of resin composite without any fiber. After 24-h water storage in 37°C distilled water, the flexural properties of each specimen were examined with static three-point flexural test at a crosshead speed of 0.5 mm/min. Results. Compared to the control without any fiber, glass and carbon fibers significantly increased the flexural strength (p < 0.05). On the contrary, the polyethylene fiber decreased the flexural strength (p < 0.05). Among the fibers, carbon fiber exhibited higher flexural strength than glass fiber (p < 0.05). Similar trends were observed for flexural modulus and fracture energy. However, there was no significant difference in fracture energy between carbon and glass fibers (p > 0.05). Conclusion. Fibers could, therefore, improve the flexural properties of resin composite and carbon fibers in longitudinal form yielded the better effects for reinforcement.