Measurements Of Storage Modulus Research Articles

A DMA-Based Approach to Quality Evaluation of Digitally Manufactured Continuous Fiber-Reinforced Composites from Thermoplastic Commingled Tow

Direct digital manufacturing of continuous fiber-reinforced thermoplastics exhibits the potential to relieve many of the constraints placed on the current design and manufacture of composite structures. At present, the additive manufacturing of continuous fiber-reinforced thermoplastics is demonstrated to varying extents; however, a comprehensive investigation of manufacturing defects and the quality of additively manufactured high fiber volume fraction continuous fiber-reinforced thermoplastic composites is limited. Considering the preliminary nature of the additive manufacturing of continuous fiber-reinforced thermoplastics, composites processed in this manner are typically subject to various manufacturing defects, including excessive void content in the thermoplastic matrix. Generally, quality evaluation of processed composites in the literature is limited to test methods that are largely influenced by the properties of the continuous fiber reinforcement, and as such, defects in the thermoplastic matrix are usually less impactful on the results and are often overlooked. Hardware to facilitate the direct digital manufacturing of continuous fiber-reinforced thermoplastic matrix composites was developed, and specimens were successfully processed with intentionally varied void content. The quality of the additively manufactured specimens was then evaluated in terms of the measured maximum storage modulus, maximum loss modulus, damping factor and the glass transition temperature by means of dynamic mechanical analysis (DMA). DMA allows for thermomechanical (i.e., highly matrix sensitive) evaluation of the composite specimens, specifically in terms of the measured elastic storage modulus, viscous loss modulus, damping factor and the glass transition temperature. Within the tested range of void contents from roughly 4–10%, evaluation by DMA resulted in a distinct reduction in the maximum measured storage modulus, maximum loss modulus and glass transition temperature with increasing void content, while the damping factor increased. Thus, the results of this work, which focused on the effect of void content on DMA measured properties, have demonstrated that DMA exhibits multi-faceted sensitivity to the presence of voids in the additively manufactured continuous fiber-reinforced thermoplastic specimens.

Characterization of storage modulus of starch suspensions during the initial stages of pasting using Stokesian dynamics simulations

This study performs Stokesian dynamics simulations of suspensions of rigid spheres to determine the conditions under which swollen starch granules can be considered rigid for rheology measurements. The first part of the study benchmarks the numerical simulations to experimental measurements of storage modulus (G′) for monodisperse polystyrene suspensions. The second part of the study compares the simulations to experimental measurements of G′ for waxy maize and normal rice starch suspensions swollen to volume fractions 0.4 < φ < 0.6. These starch granules were fractionated before swelling to create a narrow range of swollen granule sizes. For granules with a narrow size distribution, the Stokesian dynamics simulations quantitatively match the experimental G′ for volume fractions φ ≤ 0.5, but deviate significantly when φ > 0.5. These results indicate that granule deformability plays an important role when φ > 0.5, and indicates the range where one can apply theories of rigid suspension rheology.

Subcutaneously Injectable Hyaluronic Acid Hydrogel for Sustained Release of Donepezil with Reduced Initial Burst Release: Effect of Hybridization of Microstructured Lipid Carriers and Albumin

The daily oral administration of acetylcholinesterase (AChE) inhibitors for Alzheimer’s disease features low patient compliance and can lead to low efficacy or high toxicity owing to irregular intake. Herein, we developed a subcutaneously injectable hyaluronic acid hydrogel (MLC/HSA hydrogel) hybridized with microstructured lipid carriers (MLCs) and human serum albumin (HSA) for the sustained release of donepezil (DNP) with reduced initial burst release. The lipid carrier was designed to have a microsized mean diameter (32.6 ± 12.8 µm) to be well-localized in the hydrogel. The hybridization of MLCs and HSA enhanced the structural integrity of the HA hydrogel, as demonstrated by the measurements of storage modulus (G′), loss modulus (G″), and viscosity. In the pharmacokinetic study, subcutaneous administration of MLC/HSA hydrogel in rats prolonged the release of DNP for up to seven days and reduced the initial plasma concentration, where the Cmax value was 0.3-fold lower than that of the control hydrogel without a significant change in the AUClast value. Histological analyses of the hydrogels supported their biocompatibility for subcutaneous injection. These results suggest that a new hybrid MLC/HSA hydrogel could be promising as a subcutaneously injectable controlled drug delivery system for the treatment of Alzheimer’s disease.

Apparent wall slip effects on rheometric measurements of waxy gels

The effects of apparent wall slip on rheometric measurements of waxy gels are quantified for gels consisting of a macrocrystalline wax added in mineral oil in concentrations of 3.0 and 7.5 wt. %. The waxy gels are formed in situ in a stress-controlled rheometer, and rheological properties are then obtained. Seven different geometry configurations, including parallel plates, concentric cylinders, and vane, are employed. The surface roughness of the different geometries and wax crystals size are assessed to provide insight into the apparent wall slip phenomenon. In the presence of smooth surfaces, a decrease in approximately 80% in the measured yield stress value is observed in oscillatory tests, regardless of system composition. In addition, the storage modulus measurements are substantially different when obtained from smooth or grooved geometries. In creep experiments, the yield stress measurements decrease by 68%. As expected, apparent wall slip markedly affects the shape of the flow curves obtained, causing the appearance of kinks for smooth Couette geometry. Apparent slip velocities are calculated in the regime just above the yield stress, and it is found that for low concentrations apparent slip increases with concentration and decreases with the ratio between the shear stress and dynamic yield stress. The gathered results also demonstrate that the reproducibility of rheological measurements is improved by using geometries with grooved parts. By quantifying the effects of apparent wall slip on rheological measurements of waxy gels for different geometries, this work can provide useful information for the design of pipelines and oil transportation processes.

Bioactive yet antimicrobial structurally stable collagen/chitosan/lysine functionalized hyaluronic acid – based injectable hydrogels for potential bone tissue engineering applications

Novel, biocompatible, multifunctional, injectable genipin crosslinked collagen/chitosan/lysine-modified hyaluronic acid based hydrogels (ColChHAmod) were prepared in a facile, one-step procedure. The novelty of the current approach lies in the functionalization of hyaluronic acid (HA) with primary amine groups by lysine attachment, and its further use as a component of the injectable sol. The obtained derivative, HAmod, could form, upon crosslinking with genipin, covalent bonds with other components of the hydrogel network, resulting in structurally stable, better-defined hydrogels. We have demonstrated that, by adjusting HAmod content and genipin concentration, hydrogels with tunable physicochemical characteristics (swelling, wettability, tendency for enzymatic degradation) and properties adequate for the potential bone tissue regeneration can be prepared. Storage modulus measurements indicated that HAmod has positive effect on mechanical characteristics of hydrogels prepared. It was also revealed that the ColChHAmod-based hydrogels are characterized by a high porosity (85–95%). The in situ rheological measurements confirmed the injectability of the obtained hydrogels. The in vitro cell culture studies showed that the surface of all materials prepared was biocompatible, as they supported proliferation and adhesion of osteoblast-like cells followed by ALP expression. The intrinsic antibacterial activity of the hydrogels against Escherichia coli was also demonstrated in in vitro experiment.

Low-concentration salting of cod loins: The effect on biochemical properties and predicted water retention during heating

Low levels of salt are frequently used to increase flavor and water retention in cod. This alters the biochemical properties of cod during heating. In this paper, properties needed to mathematically model moisture transfer during cooking – water holding capacity and storage modulus – were determined for cod containing 0.06, 1 and 3 g/100 g NaCl. Protein denaturation and microstructure was also investigated to increase the understanding of quality effects of salt during cooking. A model was established to investigate the effect of the measured storage modulus and water holding capacity on the predicted moisture retention during heating. Salting lead to a higher water holding capacity, less hardening of the muscle tissue during heating, diffused protein denaturation peaks and caused swelling of the muscle fibers. By interchanging the acquired variables in the model of coupled heat and moisture transfer, we found a higher predicted water retention during cooking of brined cod compared to unsalted cod. This knowledge may be utilized in creating modeling tools for optimization of cooking processes, which may support chefs and ready-to-eat meal producers in reducing weight loss and improving the texture and juiciness of their products.

Evaluation of a fluorescence and infrared backscatter sensor to monitor acid induced coagulation of skim milk

Abstract A prototype sensor that employs both ultraviolet excited fluorescence and infrared light backscatter was evaluated as an in-line process analytical technology (PAT) tool to monitor acid induced coagulation kinetics of skim milk. Coagulation experiments were carried out at 32 °C using three concentrations of glucono-delta-lactone (GDL). Measurement of storage modulus (G′) of acidified skim milk gel was used as a reference rheological method to monitor the coagulation kinetics. Prediction models were developed to predict the times required for acidified skim milk coagulum to reach selected G′ values (0.5 Pa, 1 Pa, 5 Pa, 10 Pa and 15 Pa) using time parameters extracted from the ultraviolet excited fluorescence and infrared light backscatter profiles. A strong correlation was observed between the predicted times developed using time parameters extracted from the prototype sensor profiles and the measured G′ times extracted from the rheometer (R2 = 0.97, standard error of prediction = 2.8 min). This study concluded that the prototype fluorescence and infrared backscatter sensor investigated combined with the developed rheological prediction model can be used as a potential PAT tool for in-line monitoring of coagulation kinetics in the manufacture of acid induced milk gels. Industrial relevance The prototype fluorescence and infrared backscatter sensor investigated in this study combined with the developed rheological prediction model can be employed to monitor and control coagulation kinetics in a wide range of dairy processing applications including fresh cheese varieties and yoghurt manufacture.

Model for heat and mass transport during cooking of cod loin in a convection oven

Mathematical modeling of cooking of several muscle foods has been accomplished, however there are very few models predicting cooking of fish. In this study, a 3D mathematical model of transport phenomena describing baking of cod muscle in a convection oven has been developed from first principles. Several properties lacking in the literature were also determined. This includes measurements of storage modulus, water holding capacity, and the fraction of energy used for evaporation as functions of temperature. The model was validated using temperature measurements and average mass loss measurements, with good agreements.

Effect of Rheological Property of Batter on Baking Quality

Pure rice bread is possible when viscoelasticity of rice batter is suitable to keep foam structure produced in fermentation. One way to adjust viscoelasticity of rice batter for bread baking is to use amorphous rice flour that acts as a thickening agent. In this study, instead, without using amorphous rice flour, we try to find a type of rice flour that is suitable for bread baking. The molecular architecture and composition of rice starch depend on the type of rice. They affect the viscosity of rice batter. The main component of rice is starch, which is composed of amylose and amylopectin. Connected with glycosidic bonds, amylose is a linear polymer and amylopectin is a branched polymer. Fraction and branch architecture of amylopectin depend on the type of rice. The purpose of this study is to clarify how baking quality and rheological property depend on the type of rice. Names of rice type used in the present study were #4019, e1, Nipponbare, Milky Queen and Himenomochi. Type # 4019 is ultra-high amylose rice and has a molecular architecture with few branches and long double helices. Type e1 is high amylose rice and has a molecular architecture with many branches and shorter side chains. Type Nipponbare is medium-amylose rice. Type Milky Queen is low-amylose rice. Type Himenomochi is waxy rice. These three types are considered to have familiar molecular architectures for general rice starch. We baked pure rice bread from each type of rice. For bread baking, batter was composed of rice flour, water, sugar, dry yeast and salt. These materials were stirred using a mixer (KitchenAid KSM90WW; FMI Co., Ltd., Tokyo, Japan) for 10 min. After mixing, we measured 100g of the batter and put it in a loaf pan. Then we fermented in an electric fermentor (SK-15; Taisho Electric Co., Ltd., Kusatsu, Japan) for 30 min at 40°C. The batter was then baked for 15 min at 180oC in a gas oven (OZ100BOEC; Ozaki Co., Ltd., Tokyo, Japan). For rheology measurements, rice batter samples comprising only rice flour/water 50/50 (wt%) were prepared by stirring in the mixer for 10 min. We measured storage modulus G´ as a rheology data using a rotational rheometer (Physica MCR 301; Anton Paar Co., Ltd., Graz, Austria). During the measurement of G´, the temperature was increased from 25oC to 35oC at 0.3oC/min (corresponding to the temperature increase during fermentation), and from 35oC to 90oC at 2.5oC/min (corresponding to baking). The angular velocity and strain were 10 rad/s and 0.1%, respectively. A coaxial cylinder with an inner diameter of 24 mm and an outer diameter of 26 mm was used. Figure 1 shows cross-section images of baked bread samples. Batter made from high-amylose content rice showed good swelling. Bread made from ultra-high amylose rice contained large bubbles. Storage modulus G' of low-amylose rice was too low to keep bubbles for bread crumb. Figure 2 shows the storage modulus G´ obtained for rising temperature. The initial storage modulus G´ in the fermentation temperature range increased as the amylose content increased. At room temperature, linear amylose dissolves in water more easily than does branched crystalline amylopectin. We expected that amylose dissolved in water increased the viscoelasticity of the batter, causing increase of G´ of the sample. The G´ of rice batter typically increases gradually due to gelatinization up to their peak temperatures. We inferred that gelatinization occurs when water enters double helices of amylopectin. The peak value of G' showed a larger value as amylose content increased. Storage modulus G' of # 4019 showed a modest increase compared to other types. We consider that this modest increase was caused by the fact that #4019 has longer double helices than other types. Longer double helix needs longer time to completion of gelatinize. The decrease of G´above the peak temperature is caused by disintegration of starch granules. Around the peak of G’, bubbles stop growing and be stabilized. Stabilization of type # 4019 was slower than other types, so bubbles got bigger. In conclusion, difference of rice type caused difference in rheological properties of rice flour batter. When initial G ' is high, bubbles are kept. Stabilization of bubbles is faster when gelatinized temperature is lower. Figure 1

Variations in physical-chemical properties of tomato suspensions from industrial processing

Industrial tomato processing begins with a “break” step, in which the tomatoes are subjected to a thermal treatment to disrupt the fruit consistency: a low temperature break (cold break, CB; 60–77 °C) yields fresher products, whereas a high temperature break (hot break, HB; >90 °C) is used for higher viscosity products. The HB process is believed to destroy most pectolytic enzyme activity, thereby preserving the pectic matrix. This study assessed the physical/chemical basis for viscosity differences in HB and CB products. Based on serum replacement and subsequent viscosity assays, it was determined that the solubilized pectin in the serum was not a significant factor. Instead, it appears that the different temperature regimes result in the formation of particulate material, or pulp, with different rheological properties. The particle size and viscoelastic properties of the pulp differed between the two break products, indicating that differences in the particle phase may determine the viscosity differences between HB and CB products. The HB particulate material exhibited a high degree of elasticity, as indicated by its large measured storage modulus whereas the CB pulp was composed of particles having a more viscous behavior (lower storage modulus and comparable with measured loss modulus).

Enhanced self-association and “weak gel” rheology of microdispersed oxidised cellulose (MDOC) by low concentrations of guar gum

The oxidised cellulose used was a proprietary product in which ∼75% of the glucose residues are converted to glucuronate and solubility is restricted by Ca2+ cations, giving small particles that are essentially insoluble in water. Aqueous dispersions of the resulting “microdispersed oxidised cellulose” (MDOC), although pourable, give gel-like mechanical spectra at concentrations above ∼4 wt %, far below the onset of close packing, due to adhesive interactions between the particles. Changes in the “weak gel” rheology of 5 wt % dispersions of MDOC in water on progressive addition of guar gum ([η] = 12.1 dL g-1; Mr ≈ 1.42 × 106) were characterised by low-amplitude oscillatory measurements of storage modulus (G′), loss modulus (G″) and complex dynamic viscosity (η*). Increasing concentration of guar gum caused an initial increase and subsequent decrease in G’. Maximum (∼5-fold) increase was observed at very low concentration of guar gum (∼0.04 wt %). The proposed interpretation is that guar gum promotes self-association of MDOC to minimise enthalpically-unfavourable (segregative) interactions in single-phase mixtures. The decrease in G′ at concentrations above the value required for maximum enhancement of network rheology is attributed to excessive aggregation of the gelling component.

Faceted particles: An approach for the enhancement of the elasticity and the yield-stress of magnetorheological fluids

Faceted particles have been used to prepare dilute magnetorheological (MR) fluids with enhanced aggregate strength. The measured storage modulus of these suspensions is significantly larger than that of the MR fluids prepared with spherical particles, and comparable to that of the rod-based fluids, whereas no sign of formation of a percolated system was observed at the largest concentration we studied (5 vol. %). Finite element method calculations confirm that the more intimate surface contacts between faceted particles lead to larger magnetic interparticle forces than the point contacts associated with the spherical particles. The contribution of friction is expected to be significant but remains unknown.

Vertical particle alignment of boron nitride and silicon carbide binary filler system for thermal conductivity enhancement

Thermally conductive BN/SiC binary filler and epoxy composite materials were fabricated via magnetic alignment. The magnetic iron oxide particles on the surface of the filler allowed particle re-orientation under the external magnetic field. Owing to its anisotropy, the vertically aligned BN composite had a high thermal conductivity and generated a vertical heat flow path. When the SiC nanoparticles were added to the binary filler, they hindered BN-particle aggregation and led to the formation of a three-dimensional heat conduction path, thereby resulting in increased thermal conductivity. The maximum thermal conductivity (5.77 W/mK) was obtained with an addition of SiC filler, and was 3.08-fold and 1.1-fold higher than that of randomly mixed BN and vertically aligned BN composites, respectively. The additional SiC–Fe3O4 particles resulted in significant aggregation of the filler, which in turn led to a decrease in the thermal conductivity. The measured storage modulus of the BN–Fe3O4/SiC binary filler composite was also higher than those of the BN–Fe3O4 and BN–Fe3O4/SiC–Fe3O4 composites, owing to the aggregation of particles.

Experimental investigation and approximation of the temperature‐dependent stiffness of short‐fiber reinforced polymers

AbstractIn order to predict the effective material properties of a short‐fiber reinforced polymer (SFRP), homogenization of elastic properties with the self‐consistent (SC) scheme and the interaction direct derivative (IDD) method is performed by means of µCT data describing the microstructure of the composite material. Using dynamic mechanical analysis (DMA), the material properties of both, polypropylene and fiber reinforced polypropylene are investigated by tensile tests under thermal load. The measured storage modulus of the matrix material is used as input parameter for the homogenization scheme. The effective properties of SFRP are compared to experimental results from DMA. (© 2015 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Calcium induced skim-milk gelation during heating as affected by pH

Milk gels (acid or rennet) are used by dairy industry to produce dairy products such as yogurt and cheese. Enrichment of milk with calcium salts and heat treatment are known to produce “calcium-milk coagulum” as a new type of milk gels, due to reduction of milk protein charges through calcium binding. The combination of heat treatment and calcium addition to milk results in gel structures, but the effect of calcium addition and pH adjustment during heating of milk is still unclear. The role of added calcium and decreasing pH were investigated by addition of calcium chloride (30 mM) to reconstituted skim milk followed by pH adjustment by hydrochloric acid and sodium hydroxide (4.6 < pH < 6.6 investigated), followed by heating at 90 °C for 10 min and overnight storage at 22 °C. In parallel, samples with no addition of calcium chloride were produced under the same conditions. The time and temperature to reach the gelation point, as detected by dynamic measurements of storage modulus (G′), were decreasing as pH decreased without addition of calcium, while calcium addition made gelation time and temperature independent of pH except for pH 4.6. Heat treatment combined with calcium addition was found, using confocal laser microscopy, to provide a fine and dense gel structure for skim milk with higher pH, while at pH lower than 5.6, the gel structure was similar to the structure of acid-induced gels. The last observation helps to establish a pH limit for production of calcium gels.

Calcium and phosphorus equilibria during acidification of skim milk at elevated temperature

The solubilisation of calcium and phosphorus from casein micelles was studied during skim milk acidification with glucono-delta-lactone. Dynamic measurements of storage modulus (G′) as a function of time were recorded during the formation of acid milk gels with a final pH of 4.6. An abnormal change in slope of G′ (G′shoulder) as a function of time was observed at 50 and 60 °C with decreasing pH. During the appearance of G′shoulder immediately after onset of gelation there was a large change in the concentrations of serum and micellar calcium and phosphorus for change of 0.1 pH units. The onset of gelation at pH values, where the colloidal calcium phosphate is not fully solubilised, is coupled to casein micelle disintegration, and will create increased bonding between caseins forming the final acid gel with a concomitant and sudden solubilisation of calcium and phosphorus from the casein micelles.

A pH responsive Pickering emulsion stabilized by fibrous palygorskite particles

Toluene/water Pickering emulsions based on fibrous palygorskite clay particles were stabilized by increasing the solid particle concentration. The emulsion droplet size reached to a plateau at 2wt.%, suggesting the development of a three dimensional network in the emulsion. This was supported by measuring the steady state shear stress-shear rate of emulsions at different concentrations of palygorskite particles. Oscillatory rheological measurements of storage modulus G′ and loss modulus G″ were then performed to verify that the emulsion system is strongly associated at concentrations greater than 2wt.%, resulting in a viscoelastic film at the o/w interface. The role which palygorskite plays in emulsion stability by forming a three dimensional network is directly confirmed by observing the micro-morphology of palygorskite particles in the emulsions using polarizing optical microscope (POM) and transmission electron microscopy (TEM). Without any chemical modification, palygorskite fibers stabilized toluene/water Pickering emulsions over a wide range of pH (pH=1.40 to 11.44). By adding HCl/NaOH, palygorskite clay-stabilized Pickering emulsions were successfully subjected to 5 emulsification–demulsification cycles, and all of the emulsions are stable for over 3months in storage. Palygorskite has been demonstrated as an effective pH responsive emulsifier with long-term stability. The addition of NaCl leads to the aggregation and flocculation of the palygorskite particles, which increases the size of the emulsion droplets; however, stable toluene/water Pickering emulsions based on palygorskite clay can still be formed even at high NaCl concentrations.

Development of a synovial fluid analogue with bio-relevant rheology for wear testing of orthopaedic implants

The rheological properties of synovial fluid (SF) are crucial to the performance of joint prostheses. During the development of joint prostheses, wear tests are performed, which simulate joint movements in diluted solutions (usually between 25 and 33% v/v) of bovine serum which has very different rheological properties compared with native SF, where rheology is maintained by hyaluronan. Consequently, there is a need to develop a more suitable artificial SF. In this study, we used rheological techniques to understand SF flow properties which provided an insight into the mechanical behaviour required of a practical SF analogue. Steady-shear viscosity measurements were performed to reveal changes as a function of shear rate. To analyse the viscoelastic properties small deformation oscillatory measurements of storage modulus (G') loss modulus (G″) and complex viscosity (η⁎) were made. The rheological properties of the SF where compared with those of the polysaccharides sodium alginate, gellan gum and mixtures of both polymers. Initial results revealed classic shear thinning behaviour for the SF with a small Newtonian plateau at low shear rates with a gradual reduction in viscosity with increasing shear rate. Viscoelasticity measurements also showed that at low frequencies of oscillation there was a viscous response with G″ greater than G' and at higher frequencies there was an elastic response. Rheological properties were found to be similar to that of a 50:50 mix of 2% w/v high molecular weight alginate and 0.75% w/v gellan gum. Importantly, the lubricating behaviour of the serum differed significantly from the biopolymer blend over a full range of sliding velocities. The biopolymer blend was shown to lubricate the opposing surfaces more effectively. This difference was attributed to the more rapid alignment of the polysaccharide during shear when compared with the bovine albumin (the most abundant protein in serum), which typically exhibits a globular structure and has a tendency for self-association. These results suggest that polysaccharide solutions with bio-relevant rheology maybe be suitable as lubricants for in vitro orthopaedic prosthetic wear tests.

Fabrication of thermally conductive composite with surface modified boron nitride by epoxy wetting method

Boron nitride (BN) particles fabricated with different surface treatments were used to prepare thermally conductive polymer composites by epoxy wetting. The polar functionality present on the BN particles allowed the permeation of the epoxy resin because of a secondary interaction, which allowed the fabrication of a composite containing high filler concentration. The different cohesive energy densities of the synthesized material due to a functional-group-induced surface treatment effect on surface free energy and wettability determined the thermal and mechanical properties of the polymer. The results indicate that surface-curing agents interrupt the interaction between the filler and matrix, and do not always enhance thermal conductivity. Moreover, the composites showed maximum thermal conductivity at 30wt% epoxy loading when the fixed-pore volume fraction reached in the filtrated BN film. The measured storage modulus was also enhanced by surface treatment because of the sufficient interface produced and interaction between the large amount of the filler and epoxy.

Effect of carbon nanotubes on the curing and thermomechanical behavior of epoxy/carbon nanotubes composites

The processing of carbon nanotube based nanocomposites is one of the fastest growing areas in materials research due to the potential of significantly changing material properties even at low carbon nanotube concentrations. The aim of our work is to study the curing and thermomechanical behavior of carbon nanotube/epoxy nanocomposites that are critical from an application standpoint. Multiwall carbon nanotubes–epoxy composites are prepared by solvent evaporation based on a commercially available epoxy system and functionalized multiwalled carbon nanotubes. Three weight ratio configurations are considered (0.1, 0.5, and 1.0 wt%) and compared to both the neat epoxy to investigate the nano‐enrichment effect. We focus here on the modification of the curing behavior of the epoxy polymer in the presence of carbon nanotubes. It has been observed that introducing the multiwall carbon nanotubes delays the polymerization process as revealed by the modification of the activation energy obtained by differential scanning calorimetry. The viscoelastic response of the nanocomposites was studied from the measurements of storage modulus and the loss factor using dynamic mechanical analysis to evaluate the effect of the interface in each matrix/carbon nanotube system with changing matrix mobility. These measurements provide indications about the increase in the storage modulus of the composites, shift in the glass transition temperature due to the restriction of polymer chain movement by carbon nanotubes. POLYM. COMPOS., 35:441–449, 2014. © 2013 Society of Plastics Engineers