Fraction Of Multi-walled Carbon Nanotubes Research Articles

Thermal Diffusivity Behaviour of Multi-walled Carbon Nanotube Reinforced Ti6Al4V Metal Matrix Composites

This study investigated the thermal diffusivity behaviours of spark plasma sintered (SPS) multi-walled carbon nanotubes (MWCNTs) reinforced Ti6Al4V composites containing 0, 1, 2 and 3 wt. % of the reinforcement respectively, over a range of 50 – 300 °C. The MWCNTs were dispersed into the Ti6Al4V matrices by high-energy ball milling (HEBM) technique and the milled composite powders were consolidated by SPS under a vacuum atmosphere. The sintering conditions employed were heating rate (100 °C/min), holding time at temperature (5 min), sintering temperature (850 °C) and applied pressure of 50 MPa. The relative densities of the composite discs were measured according to Archimedes’ principle while the thermal diffusivities of as-sectioned composite samples were measured using the Laser Flash equipment. Relative densities of the synthesized nanocomposites deteriorated with increase in the weight fraction of MWCNTs added to Ti6Al4V. The thermal diffusivities of the composites containing 1 and 2 wt. % MWCNTs improved with increase in temperature and weight fraction of MWCNTs contents. A reverse trend was observed in the composite containing 3 wt. % MWCNTs, as the measured thermal diffusivities continued to drop with increase in temperature. Although this composite exhibited the best thermal diffusivities compared to the other composites up to 200 °C, a significant drop in thermal diffusivity was recorded between 250 and 300 °C respectively with the values lower than that of the unreinforced Ti6Al4V alloy. However, the thermal diffusivities of MWCNTs/Ti6Al4V composites were generally not dependent on their densification as the composites with higher weight fractions of the reinforcement had higher thermal diffusivities in spite of their lower relative densities.

Influence of different parameters on cured shapes and residual stresses of unsymmetric composite laminate reinforced by multi-wall carbon nanotubes

In this research, the curvature of three-phase unsymmetrical composite laminates was determined based on the Rayleigh–Ritz energy method. Three-phase composite laminate consists of glass fiber, epoxy resin and multi-walled carbon nanotubes (MWCNTs). Micromechanical models including Halpin–Tsai, modified Schapery, bridging and Schapery models have been employed to determine mechanical and thermal properties of nanocomposite plates. The influence of the thickness, curing temperature and weight fraction of MWCNTs were studied analytically. Then, some cross-ply composite specimens were fabricated and the analytical results were certified by experimental ones. Additionally, the results were compared with the Hyer model. It was observed that the proposed model can predict the curvature behavior better than the Hyer model. Study of the effects of mentioned parameters on the curvature of the cross-ply laminates revealed that addition of MWCNTs leads to increase in the elastic modulus and decrease in the CTE. So, the curvature of unsymmetrical cross-ply laminates decreases by addition of appropriate amount of nanoparticles.

Effect of carbon nanotube on cured shape of cross-ply polymer matrix nanocomposite laminates: analytical and experimental study

Cured shape of cross-ply [02/902]T fiber-reinforced composite laminates and the effect of multi-wall carbon nanotubes (MWCNTs) on the mechanical and thermal properties of laminates have been investigated. The nanocomposite laminate used in this study is composed of three phases: carbon fiber, polymer matrix and MWCNT. The volume fractions of 0%, 1%, 2% and 3% MWCNT were used to prepare nanocomposites. The mechanical and thermal properties of nanocomposites and fiber-reinforced nanocomposite laminates have been calculated by using analytical micromechanical models. Analytical micromechanical models were applied to determine the mechanical and thermal properties for two-phase nanocomposite composed of MWCNT and polymer matrix. The obtained mechanical and thermal data were considered as matrix properties and used in properties calculation of three-phase fiber-reinforced nanocomposite laminates. A developed model was used to determine curvature and the effect of MWCNT on the curvature in different specimens. Nonlinear relations have been considered for non-mid-plane strain equations. The addition of 1% volume fraction of MWCNT led to decreasing curvature and increasing critical size almost 14% and 9%, respectively, in different directions. The results were used to develop model and to compare with those calculated by Hyer model. Finally, unsymmetrical cross-ply [02/902]T laminates with different weight fractions of 0, 0.1%, 0.25% and 0.5% MWCNT were fabricated. The curvature of cured composite laminates, obtained by experimental study, was compared with that developed as Hyer models and good agreements were observed between the predicted model and experimental data. The experimentally predicted and developed model for the curvature of cross-ply [02/902]T fiber-reinforced nanocomposite laminates is better than the Hyer model.

Study on convective heat transfer and pressure drop of MWCNTs/water nanofluid in mini-tube

In recent times, the use of multi-walled carbon nanotubes (MWCNTs)/water nanofluids as a coolant has garnered immense interest due to their high thermal conductivity. Thus, this study investigates the effect of different mass fractions ( $$\varphi_{\text{w }}$$ ) of MWCNTs (0.075, 0.125 and 0.25 mass%) on forced convection heat transfer. Uniform and stable nanofluids were prepared using the two-step method coupled with the addition of water-soluble polymer polyvinyl pyrrolidone (PVP) and using high-power probe sonicator. The test was carried out in a circular mini-tube (Din = 1.1 mm), which was heated uniformly to study the developing and fully developed laminar flow. The Reynolds number (Re) varied from 200 to 500. The heat transfer coefficient was found to be significantly enhanced with increase in mass fraction of MWCNTs in the prepared nanofluid. The maximum enhancement of heat transfer coefficient was 23.9% for the nanofluid prepared with 0.25 mass% of MWCNTs. The experimental result revealed an increase in friction factor using the MWCNTs/water nanofluid. A maximum pressure drop of 9.9% was achieved for the highest mass fraction of MWCNTs.

Mechanical and Thermal Properties of Multi-scale Carbon Nanotubes–Carbon Fiber–Epoxy Composite

Multi-scale composite material was developed by combining carbon fabric and multi-wall carbon nanotubes (MWCNTs) in epoxy matrix. Varying concentrations of MWCNTs were ultrasonically dispersed in epoxy resin and applied on carbon fabric followed by curing. Tensile and flexural tests were conducted to observe the influence of MWCNTs on the mechanical properties of carbon fiber-reinforced plastic (CFRP). Coefficient of thermal expansion (CTE), thermal stability and glass transition temperature were determined through dilatometry, thermo-gravimetric analysis and differential scanning calorimetry, respectively. The MWCNTs dispersion in the epoxy was characterized through optical microscopy and scanning electron microscopy. Fractured surfaces of tensile samples were examined through high-resolution scanning electron microscope to investigate the failure mechanism. Tensile and flexural strengths were improved by 60 and 54%, respectively, on addition of 0.25 wt% MWCNTs in CFRP composite. This enhancement was attributed to the micro-crack bridging effect of the MWCNTs. Nanotubes acted as nano-stitches by holding the matrix together, thereby increasing the load bearing capability. Glass transition temperature and CTE of the CFRP was reduced by addition of MWCNTs whereas MWCNT–CFRP was found thermally stable up to 350 $${^{\circ }}$$ C. Microscopy results showed that the nanotubes were well dispersed in the epoxy matrix. However, higher weight fraction of MWCNTs in the epoxy had promoted agglomeration.

Hot‐melt adhesives based on co‐polyamide and multiwalled carbon nanotubes

ABSTRACTComposites of two hot melt adhesives based on co‐polyamides, one high viscosity (coPA_A), the other low viscosity (coPA_B), and multiwalled carbon nanotubes (MWCNTs) were prepared using twin‐screw extrusion via dilution of masterbatches. Examination of these composites across the length scales confirmed that the MWCNTs were uniformly dispersed and distributed in the polymer matrices, although some micron size agglomerations were also observed. A rheological percolation was determined from oscillatory rheology measurements at a mass fraction of MWCNTs below 0.01 for coPA_B and, between 0.01 and 0.02 for coPA_A. Significant increases in complex viscosity and storage modulus confirmed the “pseudo‐solid” like behavior of the composite materials. Electrical percolation, determined from dielectric spectroscopy was, found to be at 0.03 and 0.01 MWCNT mass fraction for coPA_A and coPA_B based composites, respectively. Addition of MWCNTs resulted in heterogeneous nucleation and altered the crystallization kinetics of both copolymers. Indirect evidence from contact angle measurements and surface energy calculations confirmed that MWCNT addition enhanced the adhesive properties of coPA_B to a level similar to coPA_A. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45999.

Synthesis and Electrical Properties of Composite Films Comprising Polymer Particles and Carbon Nanotubes

In the present study, composite films were synthesized from composite polymer particles prepared with multi-wall carbon nanotubes (MWCNTs) by in situ polymerization. Because one of the advantages of MWCNTs compared to other preparation methods is high electrical conductivity, the electrical properties of the composite films were evaluated by the direct current two-terminal method. As a result, the composite film prepared by MWCNTs had conductive paths and showed higher conductivity even at lower mass fraction of MWCNTs compared with the previous works to keep transparency. This method was shown to decrease the mass fractions of MWCNTs and increase the transparency of the composite films.

CNT network modeling and simulation of the electrical properties of CNT/PNN-PZT/epoxy paint sensor

In this study, the electrical properties of Carbon nanotubes (CNT)/PNN-PZT/epoxy paint sensor, a kind of piezoelectric composites, were simulated to explain the effect of the dispersion state of Multiwalled CNT (MWCNT) in the paint sensor on sensor characteristics. The conductivity of the CNT/PNN-PZT/epoxy paint was calculated by the 3D resistor network simulation in consideration of the length, dispersion state, and volume fraction of MWCNT. The electrical property of the paint sensor was predicted efficiently by a simple simulation method. Both the conductivity of the piezoelectric composite and the percolation threshold of MWCNT in the piezoelectric composite were simulated according to the dispersion state of MWCNT in the composite. Finally, the simulation results were compared and verified with experimental data.

Rapid in-situ reaction synthesis of novel TiC and carbon nanotubes reinforced titanium matrix composites

In-situ TiC and remained multi-walled carbon nanotubes (MWCNTs) reinforced Ti composites were synthesized using vacuum hot-press sintering and hot rolling. The effect of weight fraction of MWCNTs on microstructural evolution and mechanical properties of the Ti composites was investigated. The results indicated that both proportion and particle size of TiC increased in proportion to MWCNTs content, which resulted in different matrix microstructure, and the grains were obviously refined after rolling deformation. The hardness tests indicated that MWCNTs addition could make the composites harden, and 18.4% improvement in hardness was obtained after hot rolling. The significant improvement in both strength and hardness could be attributed to grain refinement, solid solution strengthening of carbon and dispersion strengthening of TiC particles and remained MWCNTs. A good combination of strength and ductility were achieved in Ti–1wt% MWCNTs composites, which were in accordance with the uniform distribution of smaller-sized TiC particles in Ti matrix.

Vibration, buckling and bending behavior of functionally graded multi-walled carbon nanotube reinforced polymer composite plates using the layer-wise formulation

Polymer matrix nanocomposites reinforced with uniformly dispersed and randomly oriented multi-walled carbon nanotubes (MWCNTs) are identified as excellent candidates for functionally graded structural members. This paper presents static and dynamic behavior of functionally graded polymer composite plates reinforced by randomly oriented multi-walled carbon nanotubes using novel layer-wise formulation concept. The weight fraction of MWCNTs in functional graded plate is represented by layer-wise variation along the thickness and MWCNTs are considered as uniformly dispersed in each layer. The effective elastic modulus of nanocomposite plate is predicted with modified Halpin-Tsai model, while the Poisson’s ratio and density are determined by rule of mixtures. System of governing equations are derived based on generalized higher order shear deformation (HSDT) plate theory and Navier technique is employed to obtain the solution for free-vibration, buckling and static bending problems of simply supported plates under axial and transverse loading conditions at various aspect-ratios. In order to understand the effect of important reinforcement and plate parameters on the natural frequencies, critical buckling loads and bending deflections, different parametric studies are conducted. Results reveal that different types of weight distributions have significant influence on structural characteristics.

Optimization of Drilling Parameters for Reducing the Burr Height in Machining the Silicon Carbide Particle (SiCp) Coated with Multi Wall Carbon Nano Tubes (MWCNT) Reinforced in Aluminum Alloy (A 356) Using Meta Modeling Approach

This paper explains the optimization of drilling parameters using meta modeling approach to reduce the burr height while machining Silicon Carbide Particle (SiCp) coated with Multi Wall Carbon Nano Tubes (MWCNT) and reinforced in aluminum alloy (A 356). The specimen is prepared by the combination of sonication and stir casting processes. The volume fraction of MWCNT used is 1.5% and the volume fraction of SiCp is 10%. The combination of input parameters for drilling the holes is designed using Taguchi experimental design technique. The input parameters chosen for drilling operations are spindle speed, feed rate and drill diameter. The ranges of input parameters are listed in Table 1. The tools used for drilling operation are made up of solid carbide drill bit. Meta model is a mathematical and statistical model whose second-order model can be fitted by factorial design. The optimization model can be improved significantly by the second-order model compared to the first-order model. Twenty-seven holes are drilled using vertical machining center in the prepared specimen (A 356/MWCNT coated SiCp). Desirability function shows the optimized values of input parameters to obtain minimum burr height. Meta modeling approach is used to design a model using input parameters and output response burr height. The residuals plot shows the predicted values are closer to the measured values. This plot explains that the Meta model is adequately used to predict the burr height. The optimized values of input parameters for obtaining minimum burr height are the combination of high speed, low feed and low drill diameter. The minimum value of burr height observed in this experiment is 0.002mm and it is obtained in the optimized combination of N3, f1 and d1.

Experimental investigation of heat transfer and pressure drop characteristics of non-Newtonian nanofluids flowing in the shell-side of a helical baffle heat exchanger with low-finned tubes

An aqueous solution of Xanthan Gum (XG) at a weight fraction as high as 0.2% was used as the base liquid, the stable MWCNTs-dispersed non-Newtonian nanofluids at different weight factions of MWCNTs was prepared. The base fluid and all nanofluids show pseudoplastic (shear-thinning) rheological behavior. Experiments were performed to compare the shell-side forced convective heat transfer coefficient and pressure drop of non-Newtonian nanofluids to those of non-Newtonian base fluid in an integrally helical baffle heat exchanger with low-finned tubes. The experimental results showed that the enhancement of the convective heat transfer coefficient increases with an increase in the Peclet number and the nanoparticle concentration. For nanofluids with 1.0, 0.5 and 0.2 wt% of multi-walled carbon nanotubes (MWCNTs), the heat transfer coefficients respectively augmented by 24.3, 13.2 and 4.7% on average and the pressure drops become larger than those of the base fluid. The comprehensive thermal performance factor is higher than one and increases with an increasing weight fraction of MWCNTs. A remarkable heat transfer enhancement in the shell side of helical baffle heat exchanger with low-finned tubes can be obtained by adding MWCNTs into XG aqueous solution based on thermal resistance analysis. New correlations have been suggested for the shell-side friction coefficient and the Nusselt numbers of non-Newtonian nanofluids and give very good agreement with experimental data.

Facile fabrication of PVA composite fibers with high fraction of multiwalled carbon nanotubes by gel spinning

Poly(vinyl alcohol) (PVA) composite fibers with high fraction of multiwalled carbon nanotubes (MWCNTs) were prepared by gel spinning process. Here, a modified process was introduced to prepare concentrated PVA/MWCNTs/DMSO spinning dope, and to attain good dispersion of MWCNTs in the fibers. The final composite fibers were studied by thermogravimetric analyzer (TGA), Fourier transform infrared spectrometer (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC), and WAXD analysis. The total content of MWCNTs in PVA composite fibers, from 5 to 30 wt%, was confirmed by TGA analysis. FTIR and Raman measurements demonstrated the existence of strong hydrogen interaction between MWCNTs and PVA matrix. SEM images of composite fibers showed smooth surface, regular cross‐section shape and good dispersion of MWCNTs in the fibers. DSC analysis showed that the crystallinity first increased and then decreased with the increase of MWCNTs contents. It can be concluded that low concentration of MWNCTs can act as nucleation sites for crystallization of PVA component, and large amount of MWCNTs may impede the crystallization of PVA component. The WAXD analysis results indicated that the crystal orientation of the PVA component in PVA composite fibers is almost identical at the same drawn ratio. Polarized Raman analysis indicated a small increase in MWCNTs orientation for the composite fibers. The mechanical properties tests showed that the composite fibers exhibit significant improvement in tensile strength and modulus as compared to the neat PVA fibers. The composite fibers also showed sustained growth in electrical conductivity. POLYM. ENG. SCI., 58:37–45, 2018. © 2017 Society of Plastics Engineers

The experimental and statistical investigation of the photo degradation of methyl orange using modified MWCNTs with different amount of ZnO nanoparticles

The main goal of this paper is the experimental and statistical investigation of the photo decomposition of methyl orange using decorated multi-walled carbon nanotubes (MWCNTs) with different amount of ZnO nanoparticles (MWCNT–ZnO). The synthesized photocatalysts are characterized by FTIR and TEM. The synthesis of ZnO nanoparticles in the all synthesized photocatalysts is confirmed using FTIR analysis. TEM results depict that the outer surface of MWCNTs have been successfully decorated with ZnO nanoparticles and enhancement of ZnO precursor leads to the augmentation of decorated ZnO nanoparticles. The photocatalytic performance investigation reveals that the photo degradation of methyl orange increases with respect to the UV irradiation time and weight fraction of different kinds of MWCNT–ZnO. However, the influence of weight fraction (0.1, 0.2 and 0.5% wt) on the decomposition of pollutant is higher than that of UV irradiation time (ranging from 5 to 30 min). The results show that the enhancement of decorated ZnO nanoparticles on the surface of MWCNTs leads to the increasing the photo decomposition of methyl orange. The statistical analysis using Duncan’s multiple range test confirms that there is a significant difference between different studied levels of UV irradiation time and weight fraction of MWCNT–ZnO in all of the prepared suspensions.

Electrical conductivity of melt-spun thermoplastic poly(hydroxy ether of bisphenol A) fibres containing multi-wall carbon nanotubes

Fibres spun from thermoplastic poly(hydroxy ether of bisphenol A) filled with weight fractions of 1, 3, 6, 8 and 12 wt.% of multi-wall carbon nanotubes (MWCNTs) were prepared at elevated process temperatures using a three-roll-mill for homogeneous dispersion of the MWCNTs and a twin-screw compounder with an attached winding roll for fibre spinning. Production caused fibre draw down ratios (DDR) from 1 to a maximum of 54 resulting in fibre diameters from 0.7 mm down to 0.07 mm were used. The state of dispersion of the MWCNTs was characterized by transmission electron microscopy (TEM). The electrical resistivity of the fibres and the percolation threshold were obtained as a function of weight fraction of MWCNTs and the fibre draw down ratio. The effect on resistivity of a subsequent heat treatment at 180 °C and on dissolution of the fibre’s outer layers were analysed when embedded in liquid epoxy resin. Percolation thresholds between 6 wt.% and 12 wt.% were estimated depending on the draw down ratio of the fibres. The observed lowest resistivity was about 5 Ωm for as spun fibres without drawing. It increases over several orders of magnitude to the limit of measurability with increasing the draw down ratio. It was further shown that the resistivity greatly reduced after heat treatment, as well as after embedding the fibres in epoxy resin due to the effect of near surface solubility of the thermoplastic fibre when in contact to the epoxy resin. A reduced percolation threshold of about 6 wt.% can be obtained after heat treatment. Thereby, the production related influence of fibre stretching is largely eliminated.

Dielectric behavior of a flexible three-phase polyimide/BaTiO3/multi-walled carbon nanotube composite film

A three-phase composite film was produced by inserting multi-walled carbon nanotubes (MWCNTs) and BaTiO3 nanoparticles into polyimide (PI). The combination of in-situ polymerization and water-based preparation involved in the experiment ensured fillers’ homogeneous dispersion in the matrix, which led to flexible shape of the composite films. The dielectric properties of composite films as a function of the frequency and the volume fraction of MWCNTs were studied. Such composite film displayed a high dielectric constant (314.07), low dielectric loss and excellent flexibility at 100[Formula: see text]Hz in the neighborhood of percolation threshold (9.02 vol%) owing to the special microcapacitor structure. The experimental results were highly consistent with the power law of percolation theory.

Facile synthesis of BaTiO3 on multiwalled carbon nanotubes as a synergistic microwave absorber

Microwave absorbing composites composed of both multi-walled carbon nanotubes (MWCNTs) and Barium titanatena (BaTiO3) nanoparticles as absorbers were prepared by sol–gel method. The structure and morphology of the BaTiO3/MWCNTs nanocomposites were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The complex permittivity and permeability of the BaTiO3/MWCNTs nanocomposites were measured and then the reflection loss (RL) was calculated in the frequency range of 1–18 GHz. The sample ωm = 2.5 % (the mass fraction of MWCNTs is denoted as ωm hereafter) has the minimum reflection loss of −34.4 dB at 15.1 GHz compared with the other samples at the same thickness of 1.4 mm and the effective bandwidth(RL < −10 dB) is even wider than 3.5 GHz, ranging from 13.8 to 17.4 GHz. Furthermore, the sample ωm = 2.5 % can reach −47.9 dB at 7.1 GHz with the thickness of 7.0 mm and the effective bandwidth almost covers 10 GHz with the thickness ranging from 1.4 to 9.0 mm. The obtained BaTiO3/MWCNTs nanocomposites may become an ideal microwave absorber with thin thickness, broad bandwidth and strong absorption. Good absorption properties at a low MWCNTs loading provide an added advantage in terms of ease of processability, MWCNTs filler saving and overall process economics.

Measurement of thermal conductivity, viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids

This article studied experimentally the effect of multi-wall carbon nanotubes (MWCNTs) on the thermo physical properties of ionic liquid-based nanofluids. The nanofluids were composed of ionic liquid, 1-ethyl-3-methylimidazolium diethylphosphate [EMIM][DEP], or its aqueous solution[EMIM][DEP](1)+H2O(2) and MWCNTs without any surfactants. The thermal conductivity, viscosity and density of the nanofluids were measured experimentally. The effects of the mass fraction of MWCNTs, temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied. Results show that the thermal conductivity of nanofluids increases within the range of 1.3%–9.7% compared to their base liquids, and have a well linear dependence on temperature. The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids. Finally, the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.

Wet spinning of PVA composite fibers with a large fraction of multi-walled carbon nanotubes

PVA composites fibers with a large fraction of multi-walled carbon nanotubes modified by both covalent and non-covalent functionalization were produced by a wet-spinning process. Model XQ-1 tensile tester, thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry, and wide-angle X-ray diffraction were used to characterize the properties of PVA/MWNT composite fibers. The TGA results suggested that MWNTs content in composite fibers were ranged from 5.3wt% to 27.6wt%. The mechanical properties of PVA/MWNT composite fibers were obviously superior to pure PVA fiber. The Young׳s modulus of composite fibers enhanced with increasing the content of MWNTs, and it rised gradually from 6.7GPa for the pure PVA fiber to 12.8GPa for the composite fibers with 27.6wt% MWNTs. Meanwhile, the tensile strength increased gradually from 0.39GPa for the pure PVA fiber to 0.74GPa for the composite fibers with 14.4wt% MWNTs. Nevertheless, the tensile strength of the composite fibers decreased as the MWNTs content up to 27.6wt%. SEM results indicated that the MWNTs homogeneously dispersed in the composite fibers, however some agglomerates also existed when the content of MWNTs reached 27.6wt%. DSC results proved strong interfacial interaction between MWNTs and PVA chain, which benefited composite fibers in the efficient stress-transfer. WXAD characterization showed that the orientation of PVA molecules declined from 94.1% to 90.9% with the increasing of MWNTs content. The good dispersibility of MWNTs throughout PVA matrix and efficient stress-transfer between MWNTs and PVA matrix may contributed to significant enhancement in the mechanical properties.

Lightweight MWCNTs-g-PAN Carbon Fiber Precursors. Sensitive High Absorptivity and Novel Wide-Bandgap Conjugated Polymers

We report the fabrication of lightweight MWCNTs-g-PAN carbon fiber precursors as high absorptivity and wide-bandgap novel materials. The synthesis of carbon fiber precursors was performed via the grafting process of polyacrylonitrile on the surface of acid functionalized multiwalled carbon nanotubes. 1H NMR and FTIR spectroscopic techniques revealed a successful grafting process, and the formation of MWCNTs-g-PAN fibers with the extent of stabilization (i.e., degree of conjugation) equals 3.0. Such carbon fiber precursors with 200–600 μm thickness demonstrate excellent thermal stability with three degradation steps at 276, 413, and 850 °C, respectively. Carbon fiber precursors display selective high absorption UV radiation and sharp discrete energy difference at 284 nm. They demonstrate linear dependence of absorptivity (e) on weight fraction of multiwalled carbon nanotubes in the carbon fiber precursors (χCNTs). Large absorptivity of UV radiation occurs using χCNTs (%) = 0.50 specimen due to long chain a...