The effect of carbon nanotube on the physical properties of poly(butylene terephthalate) nanocomposite by simple melt blending

Polyester nanocomposites based on poly(butylene terephthalate) (PBT) and carbon nanotube (CNT) were prepared by simple melt blending using a twin‐screw extruder. There is significant dependence of the thermal, rheological, and mechanical properties of the PBT nanocomposites on the concentration and dispersion state of CNT. The storage and loss moduli of the PBT nanocomposites increased with increasing frequency, and this enhancing effect was more pronounced at lower frequency region. The nonterminal behavior for the PBT nanocomposites was attributed to the nanotube–nanotube or polymer–nanotube interactions, and the dominant nanotube–nanotube interactions at high CNT content resulted in the formation of the interconnected network‐like structures of CNT in the PBT nanocomposites. The incorporation of a small quantity of CNT into the PBT matrix can substantially improve the mechanical properties, the heat distortion temperature, and the thermal stability of the PBT nanocomposites. The unique character of CNT dispersed in the PBT matrix resulted in the physical barrier effect against the thermal decomposition, leading to the improvement in the thermal stability of the PBT nanocomposites. This study also provides a design guide of CNT‐reinforced PBT nanocomposites with a great potential for industrial uses. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of modified carbon nanotube on physical properties and crystallization behavior of poly(ethylene terephthalate) nanocomposite

Poly(ethylene terephthalate) (PET) nanocomposites reinforced with a very small quantity of modified carbon nanotube (CNT) were prepared by melt compounding using a twin‐screw extruder. The introduction of carboxylic acid groups on the surfaces of the nanotube leads to the enhanced interactions between the nanotube and the polymer matrix through hydrogen bonding formation. The thermal stability, mechanical, and rheological properties of the PET nanocomposites are strongly dependent on the interfacial interactions between the PET and the modified CNT as well as the dispersion of the modified CNT in the PET. The introduction of the nanotube can significantly influence the non‐isothermal crystallization behavior of the PET nanocomposites. This study demonstrates that a very small quantity of the modified CNT can substantially improve the thermal stability and mechanical properties of the PET nanocomposites, depending on the dispersion of the modified CNT and the interfacial interactions between the polymer matrix and the modified CNT. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

A facile route to develop electrical conductivity with minimum possible multi‐wall carbon nanotube (MWCNT) loading in poly(methyl methacrylate)/MWCNT nanocomposites

Today, we stand at the threshold of exploring carbon nanotube (CNT) based conducting polymer nanocomposites as a new paradigm for the next generation multifunctional materials. However, irrespective of the reported methods of composite preparation, the use of CNTs in most polymer matrices to date has been limited by challenges in processing and insufficient dispersability of CNTs without chemical functionalization. Thus, development of an industrially feasible process for preparation of polymer/CNT conducting nanocomposites at very low CNT loading is essential prior to the commercialization of polymer/CNT nanocomposites. Here, we demonstrate a process technology that involves in situ bulk polymerization of methyl methacrylate monomer in the presence of multi‐wall carbon nanotubes (MWCNTs) and commercial poly(methyl methacrylate) (PMMA) beads, for the preparation of PMMA/MWCNT conducting nanocomposites with significantly lower (0.12 wt% MWCNT) percolation threshold than ever reported with unmodified commercial CNTs of similar qualities. Thus, a conductivity of 4.71 × 10^?5 and 2.04 × 10^?3 S cm^?1 was achieved in the PMMA/MWCNT nanocomposites through a homogeneous dispersion of 0.2 and 0.4 wt% CNT, respectively, selectively in the in situ polymerized PMMA region by using 70 wt% PMMA beads during the polymerization. At a constant CNT loading, the conductivity of the composites was increased with increasing weight percentage of PMMA beads, indicating the formation of a more continuous network structure of the CNTs in the PMMA matrix. Scanning and transmission electron microscopy studies revealed the dispersion of MWCNTs selectively in the in situ polymerized PMMA phase of the nanocomposites. Copyright © 2012 Society of Chemical Industry     

Influence of rubber content on mechanical,thermal, and morphological behavior of natural rubber toughened poly(lactic acid)–multiwalled carbon nanotube nanocomposites

The effects of natural rubber (NR) on the mechanical, thermal, and morphological properties of multiwalled carbon nanotube (CNT) reinforced poly(lactic acid) (PLA) nanocomposites prepared by melt blending were investigated. A PLA/NR blend and PLA/CNT nanocomposites were also produced for comparison. The tensile strength and Young's modulus of PLA/CNT nanocomposites improved significantly, whereas the impact strength decreased compared to neat PLA. The incorporation of NR into PLA/CNT significantly improved the impact strength and elongation at break of the nanocomposites, which showed approximately 200% and 850% increases at 20 wt % NR, respectively. However, the tensile strength and Young's modulus of PLA/NR/CNT nanocomposites decreased compared to PLA/CNT nanocomposites. The morphology analysis showed the homogeneous dispersion of NR particles in PLA/NR/CNT nanocomposites, while CNTs preferentially reside in the NR phase rather than the PLA matrix. In addition, the incorporation of NR into PLA/CNT lowered the thermal stability and glass‐transition temperature of the nanocomposites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44344.     

Effects of filler geometry on internal structure and physical properties of polycarbonate composites prepared with various carbon fillers

BACKGROUND: The effects of filler geometry are important for understanding the internal structure and physical properties of polymer composites. To investigate the effects of filler geometry on electrical conductivity as well as morphological and rheological properties, three types of polycarbonate (PC) composites were prepared by melt compounding with a twin‐screw extruder. RESULTS: The electrical conductivity of PC/carbon black (CB) and PC/graphite (carbon) nanofibre (CNF) composites did not show a percolation threshold through the entire filler loading ranges. However, PC‐blend‐carbon nanotube (CNT) composites showed a percolation electrical threshold for a filler loading of 1.0 to 3.0 wt% and their maximum electrical conductivity approached 10^?3 S m^?1. PC‐blend‐CB and PC‐blend‐CNF composites showed Newtonian behaviour like pure PC matrix, but PC‐blend‐CNT composites showed yield stress as well as increased storage modulus and strong shear thinning behaviour at low angular frequency and shear rate due to strong interactions generated between CNT–CNT particles as well as PC molecules and CNT particles on the nanometre scale. CONCLUSIONS: The electrical conductivity of the PC composites with different carbon constituents was well explained by the continuous network structure formed between filler particles. The network structure was confirmed by the good dispersion of fillers as well as by the yield stress and solid‐like behaviour observed in steady and dynamic shear flows. Copyright © 2009 Society of Chemical Industry     

In situ preparation of polyimide/amino‐functionalized carbon nanotube composites and their properties

In order to improve the dispersion of carbon nanotubes (CNTs) in polyimide (PI) matrix and the interfacial interaction between CNTs and PI, 4,4′‐diaminodiphenyl ether (ODA)‐functionalized carbon nanotubes (CNTs‐ODA) were synthesized by oxidation and amidation reactions. The structures and morphologies of CNTs‐ODA were characterized using Fourier transform infrared spectrometer, transmission electron microscopy, and thermal gravimetric analysis. Then a series of polyimide/amino‐functionalized carbon nanotube (PI/CNT‐ODA) nanocomposites were prepared by in situ polymerization. CNTs‐ODA were homogeneously dispersed in PI matrix. The influence of CNT‐ODA content on mechanical properties of PI/CNT‐ODA nanocomposites was investigated. It was found that the mechanical properties of nanocomposites were enhanced with the increase in CNT‐ODA loading. When the content of CNTs‐ODA was 3 wt%, the tensile strength of PI/CNT‐ODA nanocomposites was up to 169.07 MPa (87.11% higher than that of neat PI). The modulus of PI/CNTs‐ODA was increased by 62.64%, while elongation at break was increased by 66.05%. The improvement of the mechanical properties of PI/CNT‐ODA nanocomposites were due to the strong chemical bond and interfacial interaction between CNTs‐ODA and PI matrix. POLYM. COMPOS., 35:1952–1959, 2014. © 2014 Society of Plastics Engineers     

Morphology,mechanical properties and electromagnetic shielding effectiveness of poly(styrene‐b‐ethylene‐ran‐butylene‐b‐styrene)/carbon nanotube nanocomposites: effects of maleic anhydride,carbon nanotube loading and processing method

Nanocomposites based on poly(styrene‐b‐ethylene‐ran‐butylene‐b‐styrene) (SEBS) and carbon nanotubes (CNTs) (SEBS/CNT) as well as SEBS grafted with maleic anhydride (SEBS‐MA)/CNT were successfully prepared for electromagnetic shielding applications. Both SEBS/CNT and SEBS‐MA/CNT nanocomposites were prepared by melt compounding and were post‐processed using two different techniques: tape extrusion and compression moulding. The different nanocomposites were characterized by Raman spectroscopy and rheological analysis. Their mechanical properties, electrical properties (10^-2–10⁵ Hz) and electromagnetic shielding effectiveness (8.2–12.4 GHz) were also evaluated. The results showed that the CNT loading amount, the presence of MA in the matrix and the shaping technique used strongly influence the final morphologies and properties of the nanocomposites. Whilst the nanocomposite containing 8 wt% CNTs prepared by compression moulding presented the highest electromagnetic shielding effectiveness (with a value of 56.73 dB, which corresponds to an attenuation of 99.9996% of the incident radiation), the nanocomposite containing 5 wt% CNTs prepared by tape extrusion presented the best balance between electromagnetic and mechanical properties and was a good candidate to be used as an efficient flexible electromagnetic interference shielding material. © 2018 Society of Chemical Industry     

Effects of retainer frame,irradiance level and specimen thickness on cone calorimeter test results

The effects of retainer frame use, irradiance level and specimen thickness were studied as the second phase work of a round robin project on the cone calorimeter. The project was conducted in support of various U.S. building code groups, developing a system to determine the degrees of combustibility of building materials. The results of the second phase and a comparison with the corresponding round robin results conducted at 75 kW/m² according to the Board for the Coordination of the Model Codes (BCMC) protocol, are presented here. For most of the materials, no significant differences in parameters measured in the cone calorimeter were found when the retainer frame was not used, versus when the retainer frame was used. The irradiance of 50 kW/m² compared with 75 kW/m² produced significantly longer ignition times (with one exception) and lower heat‐release‐related variables as expected. The exception was gypsum board, for which heat release related values were usually higher at 50 kW/m² than at 75 kW/m². The specimen thickness effect could not be studied adequately due to the small number of tests conducted. A significant thickness effect was shown for the heat‐release‐related variables but not for time to ignition. The effect, however, was opposite for polyurethane foam in comparison with cellulosic materials. Copyright © 2004 John Wiley & Sons, Ltd.     

Electrical and mechanical properties of acrylonitrile‐butadiene‐styrene/multiwall carbon nanotube nanocomposites prepared by melt‐blending

The electrical properties in polymer/carbon nanotube (CNT) nanocomposites are governed not only by the degree of dispersion but also to a greater extent on the aspect ratio of the CNTs in the final composites. Melt‐mixing of polymer and CNTs at high shear rate usually breaks the CNTS that lowers the aspect ratio of the nanotubes. Thus, homogeneous dispersion of CNTs while retaining the aspect ratio is a major challenge in melt‐mixing. Here, we demonstrate a novel method that involves melt‐blending of acrylonitrile‐butadiene‐styrene (ABS) and in situ polymerized polystyrene (PS)/multiwalled CNT (MWCNT) nanocomposites, to prepare electrically conducting ABS/MWCNT nanocomposites with very low CNT loading than reported. The rationale behind choosing PS/MWCNT as blending component was that ABS is reported to form miscible blend with the PS. Thus, (80/20 w/w) ABS/(PS/MWCNT) nanocomposites obtained by melt‐blending showed electrical conductivity value ≈1.27 × 10^?6 S cm^?1 at MWCNT loading close to 0.64 wt %, which is quite lower than previously reported value for ABS/MWCNT system prepared via solution blending. Scanning electron microscopy and differential scanning calorimetry analysis indicated the formation of homogenous and miscible blend of ABS and PS. The high temperature (100°C) storage modulus of ABS (1298 MPa) in the nanocomposites was increased to 1696 MPa in presence of 0.64 wt % of the MWCNT. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of alumina nanoparticles on the thermal properties of carbon fibre‐reinforced composites

In this work, we investigated the thermal behaviour of a carbon‐fibre composite impregnated with nano‐alumina‐based nanocomposites. First of all, we demonstrated that it is possible to obtain good dispersion and distribution of nanoparticles by mechanical mixing. In all the studied filler percentages, the presence of the ceramic filler did not affect the processability of the blends and the mechanical properties of the composites. First, the thermal stability of the nanocomposites was investigated by thermogravimetric analysis (TGA). Then, the fire reaction of the fibre‐reinforced composites was studied at different heat fluxes, by TGA, cone calorimeter and exposure to a direct flame. In presence of an oxidizing hyperthermal environment, the experimental data suggested the role of ceramic particles as anti‐oxidizer agent for the char and the carbon fibres. Moreover, the use of alumina nanoparticles allowed a slight reduction of heat release rate. Particularly at a heat flux of 35 kW/m², the burnt material containing the higher quantity of nano‐alumina maintained a residual structural integrity because of the higher presence of char that bound together the fibres. To estimate the integrity of the composites after exposure to a direct flame (heat flux 500 kW/m²), mechanical tests were carried out on the burnt specimens. Copyright © 2013 John Wiley & Sons, Ltd.     

Fire behaviour of polyester–clay nanocomposites

The aim of this study was on the one hand, to compare the fire behaviour of polyester/clay nanocomposites with that of the neat polymers added with the conventional flame retardant melamine isocyanurate (MIC) and on the other hand, to study the effect of the flame retardant added to the nanocomposites. Polyester/clay nanocomposites were prepared by using polybutylene terephthalate (PBT) and a co‐polyester elastomer as polymeric matrices and a commercial organoclay as filler. As verified by X‐ray diffractometry (XRD) and transmission electron microscopy (TEM) intercalated structures were obtained by mixing the molten polymer with the layered silicate in a corotating twin screw extruder. The fire behaviour of these materials was investigated by means of an oxygen consumption calorimetry (Cone Calorimeter). Peak heat release rate of 3‐mm thick samples measured at 50 kW/m² external heat flux was reduced by a factor of 2–3 by the addition of organically modified montmorillonite to the polymers. The further addition of MIC did not give a significant improvement in the behaviour of the materials. Copyright © 2005 John Wiley & Sons, Ltd.     

Morphology and properties of electrically and rheologically percolated PLA/PCL/CNT nanocomposites

Poly(lactic acid)/poly(?‐caprolactone)/carbon nanotube (PLA/PCL/CNT) nanocomposites (NCs) were melt‐processed in a conventional industrial‐like twin‐screw extruder maintaining a constant PLA/PCL 80/20 wt. ratio. CNTs located in the thermodynamically favored PCL phase and, as a result, the “sea–island” morphology of the unfilled blend was replaced by a more continuous PCL dispersed phase in the ternary NCs. Rheological and electrical percolation took place at the same CNT contents (over 1.2 wt %) that TEM images suggest continuity of the PCL phase. The electrical and the low‐strain mechanical behaviors upon CNT addition were similar in the reference binary PLA/CNT and ternary PLA/PCL/CNT NCs. In the percolated NCs, the conductivity became 10⁶–10⁷ times higher than in the insulating compositions, while the Young modulus increased linearly upon the addition of CNT (12% increase at 4.9 wt % loading). Moreover, all the PLA/PCL/CNT NCs showed a ductile behavior (elongation at break >130%) similar to that of the unfilled PLA/PCL blend (140%), in contrast to the brittle behavior of binary PLA/CNT NCs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45265.     

Aramid–multiwalled carbon nanotube nanocomposites: effect of compatibilization through oligomer wrapping of the nanotubes

Aramid–multiwalled carbon nanotube (MWCNT) nanocomposites with different CNT loadings were prepared by the solution‐blending technique. Aramid oligomeric chains having reactive amine end‐groups were covalently grafted and wrapped over the surface of acid‐functionalized MWCNTs. The presence of functional groups and surface modification of MWCNTs were studied using Raman, Fourier transform infrared and X‐ray photoelectron spectroscopic and transmission/scanning electron microscopic techniques. Addition of these MWCNTs resulted in a homogeneous dispersion throughout the aramid matrix. Dynamic mechanical thermal analysis showed an increase in the storage modulus and the glass transition temperature involved with α‐relaxations on CNT loading. The coefficient of thermal expansion (CTE) of aramid was reduced on loading with such CNTs. Strong interfacial interactions of the matrix with the surface‐modified CNTs reduced the stress‐transfer problem in the composite material and resulted in higher modulus of 4.26 GPa and a glass transition temperature of 338.5 °C, whereas the CTE was reduced to 101.8 ppm °C^?1 on addition of only 2.5 wt% CNTs in the aramid matrix. © 2016 Society of Chemical Industry     

Rheological and electrical percolation thresholds of carbon nanotube/polymer nanocomposites

Percolation thresholds of multiwalled carbon nanotube/polystyrene (MWCNT/PS) nanocomposites (NC) were determined by rheology and electrical conductivity. The percolation threshold found by electrical conductivity was 0.5% carbon nanotubes (CNT) and that by mechanical spectroscopy and relaxation measurements was 0.9% CNT. These results together with those reported in the literature show several types of percolation thresholds, depending on the average filler–filler (CNT and/or aggregates) distance in a polymer matrix. A distance close to polymer gyration radius corresponds to a “soft” rheological threshold (P_{C rheo}^soft). Close contacts between fillers giving rise to a conductive path corresponds to an electrical threshold (P_{C elec}). At high filler concentration, fillers form a network, corresponding to a “rigid” rheological threshold (P_{C rheo}^rigid). These thresholds depend on the filler content and follow the order: P_{C elec}^soft < P_{C elec} < P_{C rheo}^rigid. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Effect of cooling rate on the surface resistivity of polymer/multi‐walled carbon nanotube nanocomposites

In this study, ethylene‐vinyl acetate copolymer (EVA) and polystyrene (PS) were melt‐mixed with multi‐walled carbon nanotube (CNT) (MWCNT), respectively. The effect of mixing time, rotor speed, and cooling rate on surface resistivity was investigated. EVA/MWCNT and PS/MWCNT nanocomposites with percolation threshold <1 wt% of MWCNT were prepared using conventional melt‐compounding method. When fast cooling was applied for these nanocomposites, a surface resistivity of 10⁶ Ω/square was obtained at around 7 wt% of MWCNT for EVA and 10⁵ Ω/square at around 3.5 wt% of MWCNT for PS. However, when slow cooling was applied, a surface resistivity of 10⁶ Ω/square was obtained at 0.75 wt% of MWCNT for EVA and 10⁵ Ω/square at around 0.5 wt% of MWCNT for PS. To the best of our knowledge, this is the first report which recognizes the importance of cooling rate on the surface resistivity of polymer/MWCNT nanocomposites. This finding may be potential to the commercialization of the CNT‐based polymer nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Effect of modified carbon nanotube on the properties of aromatic polyester nanocomposites

Aromatic polyester nanocomposites based on poly(ethylene 2,6-naphthalate) (PEN) and carbon nanotube (CNT) were prepared by melt blending using a twin-screw extruder. Modification of CNT to introduce carboxylic acid groups on the surface was performed to enhance intermolecular interactions between CNT and the PEN matrix through hydrogen bonding formation. Morphological observations revealed that the modified CNT was uniformly dispersed in the PEN matrix and increased interfacial adhesion between the nanotubes and the PEN, as compared to the untreated CNT. Furthermore, a very small quantity of the modified CNT substantially improved thermal stability and tensile strength/modulus of the PEN nanocomposites. This study demonstrates that the thermal, mechanical, and rheological properties of the PEN nanocomposites are strongly dependent on the uniform dispersion of CNT and the interactions between CNT and PEN, which can be enhanced by slight chemical modification of CNT, providing a design guide of CNT-reinforced PEN nanocomposites with a great potential for industrial uses.     

The characteristics of carbon nanotube‐reinforced poly(phenylene sulfide) nanocomposites

Multiwall carbon nanotube reinforced poly (phenylene sulfide) (PPS) nanocomposites were successfully fabricated through melt compounding. Structural, electrical, thermal, rheological, and mechanical properties of the nanocomposites were systematically studied as a function of carbon nanotube (CNT) fraction. Electrical conductivity of the polymer was dramatically enhanced at low loading level of the nanotubes; the electrical percolation threshold lay between 1 and 2 wt % of the CNTs. Rheological properties of the PPS nanocomposites also showed a sudden change with the CNT fraction; the percolation threshold was in the range of 0–0.5 wt % of CNTs. The difference in electrical and rheological percolation threshold was mainly due to the different requirements needed in the carbon nanotube network in different stages. The crystallization and melting behavior of CNT‐filled PPS nanocomposites were studied with differential scanning calorimetry; no new crystalline form of PPS was observed in the nanocomposites, but the crystallization rate was reduced. The thermal and mechanical properties of the nanocomposites were also investigated, and both of them showed significant increase with CNT fraction. For 5 wt % of CNT‐filled PPS composite, the onset of degradation temperature increased by about 13.5°C, the modulus increased by about 33%, and tensile strength increased by about 172%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Hydrothermal synthesis of MnO<Subscript>2</Subscript>/CNT nanocomposite with a CNT core/porous MnO<Subscript>2</Subscript> sheath hierarchy architecture for supercapacitors

MnO₂/carbon nanotube [CNT] nanocomposites with a CNT core/porous MnO₂ sheath hierarchy architecture are synthesized by a simple hydrothermal treatment. X-ray diffraction and Raman spectroscopy analyses reveal that birnessite-type MnO₂ is produced through the hydrothermal synthesis. Morphological characterization reveals that three-dimensional hierarchy architecture is built with a highly porous layer consisting of interconnected MnO₂ nanoflakes uniformly coated on the CNT surface. The nanocomposite with a composition of 72 wt.% (K_0.2MnO₂·0.33 H₂O)/28 wt.% CNT has a large specific surface area of 237.8 m²/g. Electrochemical properties of the CNT, the pure MnO₂, and the MnO₂/CNT nanocomposite electrodes are investigated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The MnO₂/CNT nanocomposite electrode exhibits much larger specific capacitance compared with both the CNT electrode and the pure MnO₂ electrode and significantly improves rate capability compared to the pure MnO₂ electrode. The superior supercapacitive performance of the MnO₂/CNT nancomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport.     

Master batch approach for developing PVDF/EVA/CNT nanocomposites with co-continuous morphology and improved electrical conductivity

Conducting polymer composites constituted by co-continuous poly (vinylidene fluoride) (PVDF)/ ethylene- vinyl acetate copolymer (EVA) blends with multiwalled carbon nanotube (CNT) were prepared by melt mixing using different procedures. The effect of the master batch approach on the conductivity, morphology, mechanical, thermal and rheological properties of PVDF/EVA/CNT nanocomposites was compared with that based on one step mixing strategy. The selective extraction experiments revealed that CNT was preferentially localized in the EVA phase in all situations, even when PVDF@CNT master batch was employed. Nanocomposites prepared with EVA@CNT master batch displayed higher conductivity, whose value reached around 10⁻¹ S m⁻¹ with the addition of 0.56 vol% of CNT. The better electrical performance was attributed to the better distribution of the filler, as indicated by transmission electron microscopy and rheological behavior. The electrical and rheological behavior were also investigated as a function of the CNT content.     

Ethylene–propylene‐diene terpolymer/halloysite nanocomposites: Thermal,mechanical properties,and foam processing

Ethylene–propylene‐diene terpolymer (EPDM)/halloysite nanotube (HNT) nanocomposites were prepared by melt mixing in an internal mixer using a commercially available maleated semicrystalline EPDM and HNT. Transmission electron microscopy analysis of the EPDM/HNT composites revealed that the HNTs are uniformly dispersed at a nanometer scale in the matrix. Differential scanning calorimeter studies indicated that the HNT caused an increase in the nonisothermal crystallization temperature of the EPDM. Tensile and dynamic mechanical analysis exhibited that a small amount of the HNTs effectively enhanced the stiffness of the EPDM without adversely affecting its elongation‐at‐break. The EPDM/HNT nanocomposites were used to produce foams by using a batch process in an autoclave, with supercritical carbon dioxide as a foaming agent. The nanocomposite foams showed a smaller cell size and higher cell density as compared to the neat EPDM foam, and the nanocomposite with 10 phr HNT produced a microcellular foam with average cell size as small as 7.8 μm and cell density as high as 1.5 × 10¹⁰ cell/cm³. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40307.