Dynamic cure kinetics of epoxy/TiO2/MWCNT hybrid nanocomposites

The effect of multi-walled carbon nanotubes (MWCNTs) on cure kinetic parameters of the epoxy/amine/TiO₂ (1 wt%) resin system was studied dynamically at four heating rates using DTA. The presence of MWCNT in various amounts (0.1, 0.2, 0.4 and 0.6 wt%) neither retarded nor accelerated the cure reaction of the epoxy/amine/TiO₂ system in a considerable extent. Addition of MWCNTs increased the extent of cure of the corresponding nanocomposites, especially at higher contents up to 0.4 wt% MWCNT filled composite. However, increasing the MWCNT content to 0.6 wt% adversely affected the extent of cure due to nanoparticle agglomeration. The fracture surface morphology of the nanocomposites revealed that the cracks deviated on reaching the MWCNTs, while propagating in the polymer matrix. Fractional extent of conversion (α) was calculated using genetic algorithm. Flynn–Wall–Ozawa and Kissinger methods were used to analyze the kinetic parameters. The presence of MWCNTs did not affect the autocatalytic cure mechanism of epoxy/amine/TiO₂ resin system and also did not cause any considerable barrier effect on the curing process. Activation energy data fitted well in the cubic polynomial regression equations and the changes of E _a with respect to α proved the autocatalytic cure mechanism, being followed by all the MWCNT-containing epoxy-based hybrid nanocomposites.     

Cure behavior and thermal stability analysis of multiwalled carbon nanotube/epoxy resin nanocomposites

As‐received multiwalled carbon nanotubes (MWCNTs) were first treated by a 3 : 1 (v/v) mixture of concentrated H₂SO₄/HNO₃ and further functionalized by ethylenediamine/dicyclohexylcarbodiimide/tetrahydrofuran solution. MWCNT/epoxy nanocomposites were prepared. Their cure behaviors were investigated by dynamic differential scanning calorimetry. Quantitative analysis of the activation energy as a function of the degree of curing was carried out by the Flynn‐Wall‐Ozawa method. The fitted multiple regression equations for values of the activation energy of different systems were obtained. MWCNTs have the retardation effect on the cure reaction of epoxy resin, while the functional groups on the surface of amine‐modified MWCNTs could accelerate the cure reactions. Thermal stability was studied by thermogravimetric analysis. The filling of amine‐modified MWCNTs is beneficial to lower the cure activation energy and improve thermal stability of the nanocomposite. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Calorimetric and rheokinetic analyses merged to capture crystallization kinetics in polyamide/clay nanocomposites: Revisiting predictability of models

Crystallization kinetics of polymer/clay systems was the subject of numerous investigations, but still there are some ambiguities in understanding thermal behavior of such systems under isothermal and nonisothermal circumstances. In this work, isothermal rheokinetic and nonisothermal calorimetric analyses are combined to demonstrate crystallization kinetics of polyamide6/nanoclay (PA6/NC) nanocomposites. As the main outcome of this work, we detected different regimes of crystallization and compared them by both isothermal dynamic rheometry and nonisothermal differential scanning calorimetry (DSC), which has not been simultaneously addressed yet. A novel analysis, somehow different from the common ones, is used to convert the storage modulus data to crystallinity values leading to more reasonable Avrami parameters in isothermal crystallization. It was found based on isothermal rheokinetic studies that increase of NC content and shear rate are responsible for erratic behavior of Avrami exponent and crystallization rates. Optimistically, however, isothermal crystallization by rheometer was confirmed by DSC. Nonisothermal calorimetric evaluations suggested an accelerated crystallization of PA6 upon increasing NC content and cooling rate. The crystallization behavior was quantified applying Ozawa (r² between 0.070 and 0.975), and combinatorial Avrami–Ozawa (r² between 0.984 and 0.998) models, where the latter appeared more appropriate for demonstration of nonisothermal crystallization of PA6/NC nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46364.     

Microwave‐assisted synthesis and characterization of polyimide/functionalized MWCNT nanocomposites containing quinolyl moiety

Polyimide‐MWCNT nanocomposites were prepared by the reaction of a heterocyclic diamine monomer of bis(4‐amino‐3,5‐dimethylphenyl)‐2‐chloro‐3‐quinolylmethane (BACQM), pyromellitic dianhydride (PMDA) with unmodified MWCNT (MWCNT), acid‐functionalized MWCNT (acid‐MWCNT) or amine‐functionalized MWCNT (amine‐MWCNT) using microwave irradiation as well as by the conventional method. The structure of the monomer was confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectral techniques. The glass transition temperature (T_g) of the MWCNTs/polyimide nanocomposite was found to be higher than that of the unfilled polyimide system. The T_g's of both systems were higher when prepared with the microwave method than the conventional synthesis. The T_g's of the nanocomposites using acid and amine functionalized MWCNTs are greater than 300°C, in both methods. This is attributed to the presence of hydrogen bond and strong covalent bond in both the acid‐MWCNT/polyimide and amine‐MWCNT/polyimide systems. The morphological studies of the nanocomposites synthesized using microwave irradiation show that a distinct MWCNT nanofibrillar network is formed in the matrix when MWCNT or acid‐MWCNT is used. A homogeneous morphology, without distinct nanotube domains is seen when the amine‐MWCNT is covalently linked to the polymer. POLYM. COMPOS., 37:2417–2424, 2016. © 2015 Society of Plastics Engineers     

Construction of improved isothermal TTT cure diagram based on an epoxy–amine thermoset

Cure degree plays a pivotal role in determining the final properties of thermosetting resin, while the parameter cannot be visually presented by the classic isothermal time–temperature-transformation (TTT) diagram. An improved isothermal TTT cure diagram is built for an epoxy–amine thermoset with the visual relationship between temperature, time, and cure degree during the whole curing. As for the improved isothermal TTT cure diagram, the curing surface and the gelation plane were developed using Vyazovkin method and rheological analysis in turn, and the variation between glass transition temperature (T _g) and curing degree was described by Dibenedetto's equation. The obtained improved isothermal TTT diagram of epoxy–amine thermoset was constructed by the combination of calorimetric and rheological analysis. The fitting results of vitrification surface and gelation plane obtained via improved isothermal TTT diagram were in good agreement with experimental results. In addition, the experimental gelation curve of epoxy–amine thermoset is directly linked to the steepest location of curing surface. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47279.     

Mechanism and kinetics of curing of diglycidyl ether of bisphenol a (DGEBA) resin by chitosan

Crosslinking behavior of Diglycidyl Ether of Bisphenol A (DGEBA) resins cured by chitosan was isothermally studied by Fourier Transform Infrared (FTIR) Spectroscopy for various molar ratios of chitosan at different temperatures. Results indicated that oxirane undergoes nucleophilic attack by the primary amine groups in chitosan to form crosslinked structure. Epoxy fractional conversion (α ) was calculated by following the change in area of oxirane peak at 914 cm^?1. Value of α and reaction rate (dα /dt ) increased with increase in curing temperature and chitosan concentration. The maximum epoxy fractional conversion of 70% was obtained for 1:4 molar ratio (Epoxy:Chitosan) at 200°C. A four parameter kinetic model with two rate constants was employed to simulate the experimental data. Overall reaction order and activation energy for all compositions were in the range of 2.5–3 and 25–50 kJ mol^?1, respectively. Results indicated that cure reaction is autocatalytic and does not follow simple n th order cure kinetics. Thermogravimetric analysis (TGA) performed on chitosan cured DGEBA films and compared against neat epoxy and neat chitosan films. Results showed that the degradation of chitosan crosslinked epoxy network occurred in the temperature range of 450–550°C. POLYM. ENG. SCI., 57:865–874, 2017. © 2016 Society of Plastics Engineers     

New polyurea MWCNTs nanocomposite films with enhanced mechanical properties

Polyurea nanocomposites represent a promising option in the development of advanced materials for applications that require high mechanical resistance. This article describes an optimized synthetic route for obtaining polyurea nanocomposites with enhanced mechanical properties by employing epoxy‐functionalized multiwalled carbon nanotubes (MWCNTs) as reinforcing agent. The experimental measurements revealed that these functionalized nanofillers have a positive effect on the properties of the composite only until they reach a certain concentration; therefore, the optimal composition was reported (the samples containing 0.2 weight % functionalized MWCNTs). The functionalization of the MWCNTs was confirmed through RAMAN, X‐ray photoelectron spectroscopy, scanning electron microscopy and thermogravimetric analysis, while the polyurea nanocomposites obtained have been characterized by thermal (differential scanning calorimetry and TGA) and mechanical (dynamic mechanical analysis and tensile tests) analyses. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45061.     

Effects of graphene oxide and chemically reduced graphene oxide on the curing kinetics of epoxy amine composites

The curing kinetics of epoxy nanocomposites prepared by incorporating graphene oxide (GO) and chemically reduced graphene oxide (rGO) have been studied using isothermal and nonisothermal differential scanning calorimetry. The kinetic parameters of the curing processes in these systems have been determined by a Kamal and Sourour phenomenological model expanded by a diffusion factor. The predicted curves determined using the kinetic parameters fit well with the isothermal DSC thermograms revealing the proposed kinetic equation clearly explains the curing kinetics of the prepared epoxy amine nanocomposites. Experimental and modeling results demonstrate the presence of an accelerating effect of the GO on the cure of the resin matrix. The use of rGO instead of GO resulted in a slight acceleration reaction rate due to the reduced presence of oxidation groups in rGO. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44803.     

Reaction kinetics modeling and thermal properties of epoxy–amines as measured by modulated‐temperature DSC. I. Linear step‐growth polymerization of DGEBA + aniline

A mechanistic approach including both reactive and nonreactive complexes can successfully simulate both nonreversing (NR) heat flow and heat capacity (C_p) signals from modulated‐temperature DSC in isothermal and nonisothermal reaction conditions for different mixtures of diglycidyl ether of bisphenol A + aniline. The reaction of the primary amine with an epoxy–amine complex initiates cure (E_1A1 = 80 kJ mol^?1), whereas the reactions of the primary amine (E_1OH = 48 kJ mol^?1) and secondary amine (E_2OH = 48 kJ mol^?1) with an epoxy–hydroxyl complex are rate determining from about 2% epoxy conversion on. The reliability of the proposed mechanistic model was verified by experimental concentration profiles from Raman spectroscopy. When cure temperatures are chosen inside or below the full cure glass‐transition region, vitrification takes place partially or completely, respectively, as can be concluded from the magnitude of the stepwise decrease in C_p. The effect of the epoxy conversion (x) and mixture composition on thermal properties such as the glass‐transition temperature (T_g), the change in heat capacity at T_g [ΔC_p(T_g)], and the width of the glass transition region (ΔT_g) are considered. The Couchman relationship, in which only T_g and ΔC_p(T_g) of both the unreacted and the fully reacted systems are needed, was evaluated to predict the T_g– x relation by using simulated concentration profiles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91:2798–2813, 2004     

Effect of carbon nanotube on PA6/ECO composites: Morphology development,rheological, and thermal properties

Thermoplastic elastomer (TPE) nanocomposites based on polyamide‐6 (PA6)/poly(epichlorohydrin‐co‐ethylene oxide) (ECO)/multiwall carbon nanotube (MWCNTs) were prepared by melt compounding process. Different weight ratios of ECO (20, 40, and 60 wt %) and two kinds of functionalized and non‐functionalized MWCNTs were employed to fabricate the nanocomposites. The morphological, rheological, and mechanical properties of MWCNTs‐filled PA6/ECO blends were studied. The scanning electron microscopy of PA6/ECO blends showed that the elastomer particles, ECO, are well‐dispersed within the PA6 matrix. The significant improvement in the dispersibility of the carboxylated carbon nanotubes (COOH‐MWCNTs) compared to that of non‐functionalized MWCNTs (non‐MWCNTs) was confirmed by transmission electron microscopy images. The tensile modulus of samples improved with the addition of both types of MWCNTs. However, the effect of COOH‐MWCNTs was much more pronounced in improving mechanical properties of PA6/ECO TPE nanocomposites. Crystallization results demonstrated that the MWCNTs act as a nucleation agent of the crystallization process resulted in increased crystallization temperature (T_c) in nanocomposites. Rheological characterization in the linear viscoelastic region showed that complex viscosity and a non‐terminal storage modulus significantly increased with incorporation of both types of MWCNTs particularly at low frequency region. The increase of rheological properties was more pronounced in the presence of carboxylic (COOH) functional groups, in the other words by addition of COOH‐MWCNTs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45977.     

Thermosetting cure diagrams: Calculation and application

The time–temperature–transformation (TTT) isothermal cure diagram and the continuous-heating-transformation (CHT) cure diagram are calculated from a reaction model for a high-T_g epoxy/amine system that has been developed to describe both epoxy/amine and etherification reactions in kinetically and diffusion-controlled reaction regimes. The cure diagrams are applied to various processing operations. The optimization of processing and of material properties by exploiting gelation and/or vitrification during cure is discussed. © 1994 John Wiley & Sons, Inc.     

Novel nitrogen‐containing epoxy resin. II. Cure kinetics by differential scanning calorimetry

The isothermal and nonisothermal cure behaviors of a novel nitrogen‐containing epoxy resin (XT resin) were studied by differential scanning calorimetry (DSC). Various kinetic parameters and details of cure process were obtained based on the Avrami theory. The results indicated that Avrami method is suitable for calculating the kinetic parameters up to the gel point at least. The apparent activation energy (E_a) for isothermal cure process was in agreement with that for nonisothermal cure process. E_a value in the early stage (78.5–81.0 KJ mol^?1) was about three times than that in the later stage (23.3–26.5 KJ mol^?1). The kinetic results from Avrami theory may present a combined effect of all factors, and which is helpful to understand the cure technique for XT–DDS system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3483–3489, 2006     

Kinetic studies of POSS–DGEBA precursors derived from monoamine functional POSS using dynamic dielectric sensing and nuclear magnetic resonance

Incorporation of pre‐reacted monofunctional polyhedral oligomeric silsesquioxane (POSS)–epoxy adducts dramatically improves dispersion of POSS in epoxy–amine networks. The relationship between reaction kinetics and mechanism for formation of POSS–epoxy adducts versus reaction temperature was investigated. Reactivities of epoxy–monoamine functional POSS molecules were determined using in situ reaction monitoring by dynamic dielectric sensing and ²⁹Si NMR spectroscopy. The amine‐functional POSS–epoxy isothermal reaction showed reduced reactivity due to reduced molecular mobility, that is, diffusion limitations. Kinetic parameters were determined by fitting ²⁹Si NMR data to the model of Kamal that was extended to include diffusion. Fitting of this model to experimental data showed very good agreement over the entire conversion range for pre‐reaction between amine‐functionalized POSS and epoxy. An autocatalytic mechanism, the same as that for the neat epoxy–amine systems, was indicated. Gel permeation chromatography, scanning electron microscopy and transmission electron microscopy were used to investigate molecular weight evolution and morphology of final networks cured by 4,4′ diaminodiphenyl sulfone using pre‐reacted POSS–epoxy adducts. POSS aggregate size decreased with increased pre‐reaction temperature; more homogenous POSS dispersion was observed with higher pre‐reaction temperature. Dynamic mechanical analysis demonstrated that T_g of composites decreased slightly compared to that of the neat matrix and there appeared to be little change in microstructural heterogeneity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45994.     

Multiwalled carbon nanotubes‐based polypropylene composites: Influence of interfacial interaction on the crystallization behavior of polypropylene

Composites of polypropylene (PP) and multi‐walled carbon nanotubes (MWCNTs) were prepared via melt‐mixing utilizing Li‐salt of 6‐amino heaxanoic acid (Li‐AHA) modified MWCNTs in the presence of a compatibilizer (polypropylene‐g‐maleic anhydride; PP‐g‐MA). Improved interaction between the anhydride group of PP‐g‐MA and the amine functionality of Li‐AHA was confirmed via FTIR and Raman spectroscopic analysis. A higher glass transition temperature (T_g) of the PP phase has been observed in these composites as compared to pristine MWCNTs‐based composites. The crystallization temperature (T_c) of the PP phase was increased as a function of pristine MWCNTs concentration in PP/MWCNTs composites indicating hetero‐nucleating action of MWCNTs. However, T_c value was decreased in the presence of Li‐AHA modified MWCNTs indicating the adsorbed Li‐AHA on the MWCNTs surface. Moreover, T_c value was higher in the presence of Li‐AHA modified MWCNTs with PP‐g‐MA as compared to that of without PP‐g‐MA, suggesting the desorbed Li‐AHA from the MWCNTs surface due to melt‐interfacial reaction. Further, MWCNTs were extracted by hot vacuum filtration technique from PP/MWCNTs composites containing Li‐AHA and PP‐g‐MA. The isothermal crystallization kinetics showed a variation in crystallization behavior of the PP phase in the corresponding composites as compared to the “extracted MWCNTs.” POLYM. ENG. SCI., 57:183–196, 2017. © 2016 Society of Plastics Engineers     

Isothermal crystallization kinetics of polypropylene in melt‐mixed composites of polypropylene and multi‐walled carbon nanotubes

The isothermal crystallization behaviour of the polypropylene (PP) phase in PP/multi‐walled carbon nanotubes (MWCNTs) composites has been investigated via differential scanning calorimetric analysis, which showed the influence of the varying dispersion level of MWCNTs in the respective PP matrix. PP/MWCNTs composites were prepared via melt‐blending technique, wherein two different grades of MWCNTs of varying average “agglomerate” size and varying entanglements (N‐MWCNTs and D‐MWCNTs) were utilized. Furthermore, the influence of melt‐viscosity of the PP phase was investigated on the crystallization kinetics of the PP/MWCNTs composites. Heterogeneous nucleation ability of MWCNTs has resulted in a decrease in half time of crystallization (t _1/2) from ～14 min for pure PP to ～6 min for PP/N‐MWCNTs and ～11 min for PP/D‐MWCNTs composites at 1 wt% of MWCNTs at 132 °C. Overall rate of crystallization (k) has significantly increased to 4.9 × 10^?2 min^?1 for PP/N‐MWCNTs composite as compared with 6.2 × 10^?3 min^?1 for PP/D‐MWCNTs composite at 0.5 wt% of MWCNTs at 132 °C. Moreover, the effect of a novel organic modifier, Li‐salt of 6‐amino hexanoic acid along with a compatibilizer (PP‐g‐MA) has also been investigated on the crystallization kinetics of the PP phase in PP/MWCNTs composites. POLYM. ENG. SCI., 57:1136–1146, 2017. © 2017 Society of Plastics Engineers     

Advanced isoconversional cure kinetic analysis of epoxy/poly(furfuryl alcohol) bio‐resin system

Furfuryl alcohol as a biomass‐derived monomer was used for synthesizing poly(furfuryl alcohol). A diglycidyl ether of bisphenol A (DGEBA) epoxy resin along with 3% and 15% by weight of the poly(furfuryl alcohol) was cured using an aliphatic amine hardener. The cure kinetics of the DGEBA/poly(furfuryl alcohol)/amine systems were investigated by nonisothermal differential scanning calorimetry. The kinetic triplets [E_α, A_α, and f(α)] were computed by using an integral isoconversional method. Based on the E_α‐dependency results a single‐step autocatalytic model was suggested for the reactions mechanism, however, the A_α‐dependency and f(α) analysis did not confirm the suggested model. Detailed kinetics analysis revealed that the cure reaction mechanism of the DGEBA did not change due to the presence of the poly(furfuryl alcohol) in the degree of conversion range < 0.75, nevertheless, it dramatically changed in the degree of conversion range > 0.75 due to the presence of 15 wt % poly(furfuryl alcohol). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45432.     

Reaction kinetics of epoxy resin modified with reactive and nonreactive thermoplastic copolymers

An epoxy resin system based on a triglycidyl p‐amino phenol (MY0510) was crosslinked using stoichiometric amounts of 4,4′‐diaminodiphenyl sulfone. The epoxy was modified with random copolymers, polyethersulfone‐poly(ether‐ethersulfone) (PES:PEES), with either amine or chlorine end groups, at 10 and 20 wt %. The reaction kinetics for both unmodified and modified epoxy systems were studied using differential scanning calorimetry in isothermal and dynamic conditions. The results show that the degree of conversion in thermoplastic‐modified epoxies at any reaction time is smaller compared with the unmodified resin. Gel point (GP) determination was done from rheological measurements. The modified system containing 20% of the PES:PEES additive showed considerable increase in the GP. The reaction rate shows the characteristic of an autocatalytic reaction where the product acts as catalyst. The activation energy, E_a calculated from the isothermal reaction depends on the extent of conversion and increases with increasing PES:PEES content. For unmodified epoxy system, the average E_a is 67.8 ± 4.1 kJ mol^?1 but for systems modified with 20 wt % of amine and chlorine PES:PEES, the value increased to 74.1 ± 3.3 and 77.9 ± 4.4 kJ mol^?1, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Isothermal Cure of an Epoxy System Containing Tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM), a Multifunctional Novolac Glycidyl Ether and 4,4′-Diaminodiphenylsulphone (DDS): Vitrification and Gelation

Times to gelation and vitrification have been determined at different isothermal curing temperatures between 200 and 240°C for an epoxy/amine system containing both tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) and a multifunctional Novolac glycidyl ether with 4,4′-diaminodiphenylsulphone (DDS). The mixture was rich in epoxy, with an amine/epoxide ratio of 0·64. Gelation occurred around 44% conversion. Vitrification was determined from data curves of glass transition temperature, T_g, versus curing time obtained from differential scanning calorimetry experiments. The minimum and maximum values T_g determined for this epoxy system were T_g0=12°C and T_gmax=242°C. Values of activation energy for the cure reaction were obtained from T_g versus time shift factors, a_T, and gel time measurements. These values were, respectively, 76·2kJmol^-1 and 61·0kJmol^-1. The isothermal time–temperature–transformation (TTT) diagram for this system has been established. Vitrification and gelation curves cross at a cure temperature of 102°C, which corresponds to glass transition temperature of the gel. © of SCI.     

Effect of amine functionalization of CNF on electrical, thermal, and mechanical properties of epoxy/CNF composites

This paper presents experimental results of the effect of amine functionalization of carbon nanofibers (CNF) on the electrical, thermal, and mechanical properties of CNF/epoxy composites. The functionalized and non-functionalized CNFs (up to 3 wt%) were dispersed into epoxy using twin screw extruder. The specimens were characterized for electrical resistivities, thermal conductivity (K), UTS, and Vicker’s microhardness. The properties of the nanocomposites were compared with that of neat epoxy. The volume conductivity of the specimens increased by E12 S/cm and E09 S/cm in f-CNF/epoxy and CNF/epoxy, respectively, at 3 wt% filler loading. The increase in K for former was 106% at 150 °C, while for the latter it was only 64%. Similarly, UTS increased by 61% vs. 45% and hardness 65% vs. 43%. T _g increased with increase in filler content. SEM examinations showed that functionalization resulted in better dispersion of the nanofibers and hence greater improvement in the studied properties of the nanocomposites.     

Thermal stability and kinetics analysis of epoxy composites modified with reactive polyol diluent and multiwalled carbon nanotubes

The effect of polyether polyol and amino‐functionalized multiwalled carbon nanotubes (NH₂‐MWCNTs) on the thermal stability of three‐phase (epoxy/polyol/NH₂‐MWCNTs) epoxy composites was investigated. Thermal stability and degradation characteristics of polyol/MWCNTs modified epoxy composites was evaluated using thermogravimetric analysis. The kinetics of thermal degradation was assessed from data scanned at 5, 10, and 20°C/min. Activation energy for degradation of epoxy nanocomposites was calculated using different differential and integral methods, that is, Kissinger's, Flynn–Wall–Ozawa, Coats–Redfern, and Horowitz–Metzger methods. In addition, the integral procedure decomposition temperature was determined to evaluate the inherent thermal stability of the modified composite system. Rate of thermal degradation in MWCNT/Polyol samples was found to be reduced significantly while activation energy of degradation was increased compared to unmodified epoxy composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41558.