in situ synthesis of biopolyurethane nanocomposites reinforced with modified multiwalled carbon nanotubes

Biopolyurethane nanocomposites reinforced with silane‐modified multiwalled carbon nanotubes (s‐MWCNT) were successfully prepared. The carbon nanotube surfaces were modified by means of functional amine groups via ozone oxidation followed by silanization. The surface structure of the s‐MWCNTs was characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The s‐MWCNTs were incorporated into a vegetable oil‐based polyurethane (PU) network via covalent bonding to prepare PU nanocomposites. The effect of s‐MWCNT loading on the morphology, thermomechanical, and tensile properties of the PU nanocomposites was studied. It was determined that the s‐MWCNTs were dispersed effectively in the polymer matrix and that they improved the interfacial strength between the reinforcing nanotubes and the polymer matrix. Storage modulus, glass transition temperature, Young's modulus, and tensile strength of the nanocomposites increased with increasing s‐MWCNT loading up to 0.8%. However, increasing the s‐MWCNT content to 1.2 wt % resulted in a decrease in thermomechanical properties of the PU nanocomposites. This effect was attributed to the fact that at high s‐MWCNT contents, the increased number of amine groups competed with the polyol's hydroxyl groups for isocyanate groups, causing a decrease in the integrity of the PU matrix. High s‐MWCNT contents also facilitated aggregation of the nanotubes, causing a decrease in thermomechanical properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42515.     

Preparation and properties of plasticized starch/multiwalled carbon nanotubes composites

In this work we have studied the utilization of multiwalled carbon nanotubes (MWCNTs) as filler‐reinforcement to improve the performance of plasticized starch (PS). The PS/MWCNTs nanocomposites were successfully prepared by a simple method of solution casting and evaporation. The morphology, thermal behavior, and mechanical properties of the films were investigated by means of scanning electron microscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry, and tensile testing. The results indicated that the MWCNTs dispersed homogeneously in the PS matrix and formed strong hydrogen bonding with PS molecules. Compared with the pure PS, the tensile strength and Young's modulus of the nanocomposites were enhanced significantly from 2.85 to 4.73 MPa and from 20.74 to 39.18 MPa with an increase in MWCNTs content from 0 to 3.0 wt %, respectively. The value of elongation at break of the nanocomposites was higher than that of PS and reached a maximum value as the MWCNTs content was at 1.0 wt %. Besides the improvement of mechanical properties, the incorporation of MWCNTs into the PS matrix also led to a decrease of water sensitivity of the PS‐based materials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Thermosetting polyurethane multiwalled carbon nanotube composites

Thermosetting polyurethane (PU) multi‐walled carbon nanotube (MWCNT) nanocomposites at loadings up to 1 wt % were prepared via an addition polymerization reaction. The morphology of the nanocomposites and degree of dispersion of the MWCNTs was studied using a combination of scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and wide angle X‐ray diffraction (WAXD), and revealed the nanotubes to be highly dispersed in the PU matrix. Addition of just 0.1 wt % MWCNTs resulted in significant enhancements in stiffness, strength and toughness. Increases in Young's modulus, % elongation at break and ultimate tensile strength of 561, 302 and 397% were measured for the nanocomposites compared to the unfilled PU. The effect of the MWCNTs on the modulus of the PU was evaluated using the Rule of Mixtures, Krenchel and Halpin‐Tsai models. Only the Halpin‐Tsai model applied to high aspect ratio nanotubes was in good agreement with the modulus values determined experimentally. Strong interfacial shear stress was found between PU chains and nanotubes, up to 439 MPa, calculated using a modified Kelly‐Tyson model. Evidence for strong interfacial interactions was obtained from the Raman spectra of both the precursor materials and nanocomposites. When the MWCNTs were added to the isophorone diisocyanate an up‐shift of 14 cm^?1 and on average 40 cm^?1 was obtained for the position of the carbon‐hydrogen (C? H) out‐of plane bending (766 cm^?1) and isocyanate symmetric stretch (1420 cm^?1) modes respectively. Moreover, an up‐shift of 24 cm^?1 was recorded for the nanotube tangential mode (G‐band) for the 1.0 wt % nanocomposite because of the compressive forces of the PU matrix acting on the MWCNTs. The dynamic mechanical (DMA) properties of the PU thermoset and the nanocomposites were measured as a function of temperature. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Improvement in properties of multiwalled carbon nanotube/polypropylene nanocomposites through homogeneous dispersion with the aid of surfactants

The effects of different surfactants on the properties of multiwalled carbon nanotubes/polypropylene (MWCNT/PP) nanocomposites prepared by a melt mixing method have been investigated. Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) were used as a means of noncovalent functionalization of MWCNTs to help them to be dispersed uniformly into the PP matrix. The effects of these surfactant‐treated MWCNTs on morphological, rheological, thermal, crystalline, mechanical, and electrical properties of MWCNT/PP composites were studied using field emission scanning electron microscopy, optical microscopy, rheometry, tensile, and electrical conductivity tests. It was found that the surfactant‐treatment and micromixing resulted in a great improvement in the state of dispersion of MWCNTs in the polymer matrix, leading to a significant enhancement of Young's modulus and tensile strength of the composites. For example, with the addition of only 2 wt % of SDS‐treated and NaDDBS‐treated MWCNTs, the Young's modulus of PP increased by 61.1 and 86.1%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and properties of polyurethane/multiwalled carbon nanotube nanocomposites by a spray drying process

A spray drying approach has been used to prepare polyurethane/multiwalled carbon nanotube (PU/MWCNT) composites. By using this method, the MWCNTs can be dispersed homogeneously in the PU matrix in an attempt to improve the mechanical properties of the nanocomposites. The morphology of the resulting PU/MWCNT composites was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). SEM and TEM observations illustrate that the MWCNTs are dispersed finely and uniformly in the PU matrix. X‐ray diffraction results indicate that the microphase separation structure of the PU is slightly affected by the presence of the MWCNTs. The mechanical properties such as tensile strength, tensile modulus, elongation at break, and hardness of the nanocomposites were studied. The electrical and the thermal conductivity of the nanocomposites were also evaluated. The results show that both the electrical and the thermal conductivity increase with the increase of MWCNT loading. In addition, the percolation threshold value of the PU composites is significantly reduced to about 5 wt % because of the high aspect ratio of carbon nanotubes and exclusive effect of latex particles of PU emulsion in dispersion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of multi‐walled carbon nanotube/poly(ethylene terephthalate) nanoweb

Multi‐walled carbon nanotube (MWCNT)/Poly(ethylene terephthalate) (PET) nanowebs were obtained by electrospinning. For uniform dispersion of MWCNTs in PET solution, MWCNTs were functionalized by acid treatment. Introduction of carboxyl groups onto the surface of MWCNTs was examined by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) analysis. MWCNTs were added into 22 wt % PET solution in the ratio of 1, 2, 3 wt % to PET. The morphology of MWCNT/PET nanoweb was observed using field emission‐scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM). The nanofiber diameter decreased with increasing MWCNT concentration. The distribution of the nanofiber diameters showed a bi‐modal shape when MWCNTs were added. Thermal and tensile properties of electrospun MWCNT/PET nanowebs were examined using a differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA) and etc. Tensile strength, tensile modulus, thermal stability, and the degree of crystallinity increased with increasing MWCNT concentration. In contrast, elongation at break and cold crystallization temperature showed a contrary tendency. Electric conductivities of the MWCNT/PET nanowebs were in the electrostatic dissipation range. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of multiwall carbon nanotube/waterborne polyurethane nanocomposites

The preparation of thermoplastic nanocomposites of waterborne polyurethane (WBPU) and multiwall carbon nanotubes (MWCNTs) via an in situ polymerization approach is presented. The effects of the presence and content of MWCNTs on the morphology and thermal, mechanical and electrical properties of the nanocomposites were investigated. Carbon nanotubes were modified with amide groups in order to enhance their chemical affinity towards WBPU. Thermogravimetric studies show enhanced thermal stability of the nanocomposites. Scanning and transmission electronic microscopy images prove that functionalized carbon nanotubes can be effectively dispersed in WBPU matrix. Mechanical properties reveal that Young's modulus and tensile strength tend to increase when appropriate amounts of MWCNTs are loaded due to the reinforcing effect of the functionalized carbon nanotubes. Thermal properties show an increase in the glass transition temperature and storage modulus with an increase in MWCNT content. X‐ray diffraction reveals better crystallization of the WBPU in the presence of MWCNTs. The WBPU/MWCNT nanocomposite film containing 1 wt% of MWCNTs exhibits a conductivity nearly five orders of magnitude higher than that of WBPU film. © 2017 Society of Chemical Industry     

Amino functionalization of multiwalled carbon nanotubes by gamma ray irradiation and its epoxy composites

In this paper, γ‐ray radiation technique was utilized to simply functionalize multi‐walled carbon nanotube (MWCNT) with amino groups. The successful amino functionalization of MWCNTs (MWCNTs‐Am) was proven and the physicochemical properties of MWCNTs before and after radiation grafting modifications were characterized using FT‐IR, X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated that the γ‐ray radiation had the visible effects on the surface properties of MWCNTs. The effects of various functionalized MWCNTs on morphological, thermal, and mechanical properties of an epoxy‐based nanocomposite system were investigated. Utilizing in situ polymerization, 1 wt% loading of MWCNT was used to prepare epoxy‐based nanocomposites. Compared to the neat epoxy system, nanocomposites prepared with MWCNT‐Am showed 13.0% increase in tensile strength, 20.0% increase in tensile modulus, and 24.1% increase in thermal decomposition temperature. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Effects of multiwall carbon nanotubes on the thermal and mechanical properties of medium density polyethylene matrix nanocomposites produced by a mechanical milling method

Medium‐density polyethylene/multiwall carbon nanotube (MDPE/MWCNT) nanocomposites were produced by a mechanical milling method using a high‐energy ball mill. The MDPE and MWCNTs were added to the ball mill at a constant 20:1 weight ratio of ball/powders and milled for 10 h to obtain polyethylene matrix nanocomposites reinforced with 0.5, 1, 2.5, and 5 weight percent of MWCNTs. To clarify the role of both MWCNT content and milling time on the morphology of MDPE, some nanocomposite samples were investigated by using a scanning electron microscope. To evaluate the role of milling on the microstructure of the nanocomposites, very thin films of MDPE/MWCNTs were prepared and studied by transmission electron microscopy. Thermal behavior of these nanocomposites was investigated by using differential scanning calorimetry (DSC). Standard tensile samples were produced by compression molding. The dependence of the tensile properties of MDPE on both milling time and MWCNT content was studied by using a tensile test. The results of the microscopic evaluations showed that the milling process could be a suitable method for producing MDPE/MWCNT nanocomposites. The addition of carbon nanotubes to MDPE caused a change in its morphology at constant milling parameters. The results of the DSC tests showed that the crystallization temperature of MDPE increased as MWCNTs were added, although no dependency was observed as milling time increased. Crystallization index changed from 50 to 55% as MWCNT content increased from 0 to 5%. The results of the tensile tests showed that both the Young's modulus and the yield strength of MDPE increased as MWCNTs were added. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers     

Improving thermal conductivity and shear strength of carbon nanotubes/epoxy composites via thiol‐ene click reaction

This study investigates the effect of the thiol‐ene click reaction on thermal conductivity and shear strength of the epoxy composites reinforced by various silane‐functionalized hybrids of sulfhydryl‐grafted multi‐walled carbon nanotubes (SH‐MWCNTs) and vinyl‐grafted MWCNTs (CC‐MWCNTs). The results of Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, thermal gravimetric analysis (TGA), and transmission electron microscopy (TEM) show that the sulfhydryl groups and vinyl groups are successfully grafted onto the surface of MWCNTs, after treatment of MWCNT with triethoxyvinylsilane and 3‐mercaptopropyltrimethoxysilane, respectively. Scanning electron microscopy (SEM), HotDisk thermal constant analyzer (HotDisk), optical microscope, and differential scanning calorimetry (DSC) are used to characterize the resultant composites. It is demonstrated that the hybrid of 75 wt % SH‐MWCNTs and 25 wt % CC‐MWCNTs has better dispersion and stability in epoxy matrix, and shows a stronger synergistic effect in improving the thermal conductivity of epoxy composite via the thiol‐ene click reaction with 2,2′‐azobis(2‐methylpropionitrile) as thermal initiator. Furthermore, the tensile shear strength results of MWCNT/epoxy composites and the optical microscopy photographs of shear failure section indicate that the composite with the hybrid MWCNTs has higher shear strength than that with raw MWCNTs. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44579.     

Mechanical and thermal properties of polyphenylene sulfide/multiwalled carbon nanotube composites

Polyphenylene sulfide (PPS)/multiwalled carbon nanotube (MWCNT) composites were prepared using a melt‐blending procedure combining twin‐screw extrusion with centrifugal premixing. A homogeneous dispersion of MWCNTs throughout the matrix was revealed by scanning electron microscopy for the nanocomposites with MWCNT contents ranging from 0.5 to 8.0 wt %. The mechanical properties of PPS were markedly enhanced by the incorporation of MWCNTs. Halpin‐Tsai equations, modified with an efficiency factor, were used to model the elastic properties of the nanocomposites. The calculated modulus showed good agreement with the experimental data. The presence of the MWCNTs exhibited both promotion and retardation effects on the crystallization of PPS. The competition between these two effects results in an unusual change of the degree of crystallinity with increasing MWCNT content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Natural rubber/multiwalled carbon nanotube composites developed with a combined self-assembly and latex compounding technique

Carbon nanotubes (CNTs), with their high aspect ratio and exceptionally high mechanical properties, are excellent fillers for composite reinforcement if they are uniformly dispersed without aggregation. Combining the latex compounding and self-assembly techniques, we prepared a novel natural rubber (NR)/multiwalled carbon nanotube (MWCNT) composite. Before self-assembly, the MWCNTs were treated with mixed acid to ensure that the MWCNTs were negatively charged under an alkaline environment. The structure of the MWCNTs was tested with Fourier transform infrared spectroscopy. The properties of composites with different MWCNT loadings were characterized with transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and tensile testing. The results indicate that the MWCNTs were homogeneously distributed throughout the NR matrix as single tubes and had good interfacial adhesion with the NR phase when the MWCNT loading was less than 3 wt %. In particular, the addition of the MWCNT led to a remarkable reinforcement in the tensile strength, with a peak value of 31.4 MPa for an MWCNT content of 2 wt %, compared to the pure prevulcanized NR (tensile strength = 21.9 MPa). The nanocomposites reinforced with MWCNTs should have wide applications because of the notable improvement in these important properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Rheological and thermal properties of poly(ethylene oxide)/multiwall carbon nanotube composites

Poly(ethylene oxide) (PEO) based nanocomposites were prepared by the dispersion of multiwall carbon nanotubes (MWCNTs) in aqueous solution. MWCNTs were added up to 4 wt % of the PEO matrix. The dynamic viscoelastic behavior of the PEO/MWCNT nanocomposites was assessed with a strain‐controlled parallel‐plate rheometer. Prominent increases in the shear viscosity and storage modulus of the nanocomposites were found with increasing MWCNT content. Dynamic and isothermal differential scanning calorimetry studies indicated a significant decrease in the crystallization temperature as a result of the incorporation of MWCNTs; these composites can find applications as crystallizable switching components for shape‐memory polymer systems with adjustable switching temperatures. The solid‐state, direct‐current conductivity was also enhanced by the incorporation of MWCNTs. The dispersion level of the MWCNTs was investigated with scanning electron microscopy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Improved dielectric performance of polypropylene/multiwalled carbon nanotube nanocomposites by solid‐phase orientation

By means of a die‐drawing technique in the rubbery state, the effect of the orientation of the microstructure on the dielectric properties of polypropylene (PP)/multiwalled carbon nanotube (MWCNT) nanocomposites was examined in this study. The viscoelastic behavior of the PP/MWCNT nanocomposites with MWCNT weight loadings ranging from 0.25 to 5 wt % and the dielectric performance of the stretched PP/MWCNT nanocomposites at different drawing speeds and drawing ratios were studied to obtain insight into the influences of the dispersion and orientation state of the MWCNTs and matrix molecular chains. A viscosity decrease (ca. 30%) of the PP/MWCNT‐0.25 wt % (weight loading) melt was obviously due to the free volume effect. Differential scanning calorimetry (DSC) and wide‐angle X‐ray diffraction were adopted to detect the orientation structure and the variation of crystal morphology of the PP/MWCNTs. Melting plateau regions, which indicated the mixed crystallization morphology for the stretched samples, were found in the DSC patterns instead of a single‐peak for the unstretched samples. We found that the uniaxial stretching process broke the conductive MWCNT networks and consequently increased the orientation of MWCNTs and molecular chains along the tensile force direction; this led to an improvement in the dielectric performance. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42893.     

Dispersion of multiwalled carbon nanotubes in polyacrylonitrile‐co‐starch copolymer matrix for enhancement of electrical,thermal, and gas barrier properties

Nanomaterials gained great importance on account of their wide range of applications in many areas. Carbon nanotubes (CNTs) exhibit exceptional electrical, thermal, gas barrier, and tensile properties and can therefore be used for the development of a new generation of composite materials. Functionalized multiwalled carbon nanotubes (MWCNTs) reinforced Polyacrylonitrile‐co‐starch nanocomposites were prepared by in situ polymerization technique. The structural property of PAN‐co‐starch/MWCNT nanocomposites was studied by X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The conductivity, tensile strength, and thermal properties of nanocomposites were measured as a function of MWCNT concentrations. The thermal stability, conductivity, and tensile strength of PAN‐co‐starch/MWCNT nanocomposites were improved with increasing concentration of MWCNTs. Oxygen barrier property of PAN‐co‐starch/MWCNT nanocomposites was calculated and it was found that, the property was reduced substantially with increase of MWCNTs proportion. The synthesized PAN‐co‐starch/MWCNT nanocomposites may used for electrostatically dissipative materials, aerospace or sporting goods, and electronic materials. © 2013 Society of Plastics Engineers     

The effect of multiwall carbon nanotubes on the properties of room temperature-vulcanized silicone adhesives

The effects of surface-functionalized and pristine multiwall carbon nanotubes (MWCNT) on the bulk and adhesion properties of silicone nanocomposites were investigated. The MWCNTs surface functionalization was carried out by silanization of methacryloxy or vinyl-based silanes. The nanocomposites were prepared using solvent mixing which enhanced distribution and dispersion of the MWCNTs in the high-viscosity silicone matrix. The quality of dispersion was evaluated using scanning electron microscopy (SEM) indicating good dispersion state. It was found that the optimal concentration of both treated and untreated MWCNTs in the nanocomposites was 1 wt.%. Above this threshold value, the nanocomposites properties were reduced. Furthermore, the silane treatment of the MWCNTs was proven to be an effective process that resulted in a significant increase in the nanocomposites properties compared to the neat polymer, leading to higher storage modulus simultaneously with up to 27% improvement in the tensile strength and elongation, 20–30% reduction in the thermal expansion coefficient, 220–300% enhancement in crystallinity (enthalpy of fusion), and up to 56% improvement in the lap shear strength. SEM analysis indicated that significant changes in the fracture morphologies occurred due to higher energy absorption in the case of silane-treated MWCNTs. It was concluded that incorporation of silane-treated MWCNTs is an effective route to reinforce and increase the toughness of silicone-based adhesives.     

Properties of carbon nanotube reinforced linear low density polyethylene nanocomposites fabricated by cryogenic ball‐milling

A cryogenic ball‐milling process to produce polymer/CNT nanocomposites was investigated. Linear low density polyethylene was used as the matrix material and 1 wt % of multiwalled carbon nanotubes (MWCNT) was used as reinforcement. The influence of the milling time and balls size was evaluated. The morphology of the nanocomposite and the degree of dispersion of the MWCNTs were studied using scanning electron microscopy (SEM), visual inspection, and light transmission microscopy; ropes as well as aggregates of MWCNTs were observed, and there was evidence of wetting of the nanotubes by the matrix polymer. An increase of up to 28% in the elastic modulus (determined by tensile testing) with respect to the matrix was obtained. Differential scanning calorimetry (DSC) analysis showed evidence of increase in the degree of crystallization, a result of the nucleating capability of the carbon nanotubes in the matrix. The degradation temperature of the nanocomposites does not show significant variations with respect to the unfilled polymer. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Low percolation threshold in polycarbonate/multiwalled carbon nanotubes nanocomposites through melt blending with poly(butylene terephthalate)

Here, we demonstrate an easy method for the preparation of highly electrically conductive polycarbonate (PC)/multiwalled carbon nanotubes (MWCNTs) nanocomposites in the presence of poly(butylene terephthalate) (PBT). In the presence of MWCNTs, PC and PBT formed a miscible blend, and the MWCNTs in the PC matrix were uniformly and homogeneously dispersed after the melt mixing of the PC and PBT–MWCNT mixture. Finally, when the proportion of the PC and PBT–MWCNT mixture in the blend/MWCNT nanocomposites was changed, an electrical conductivity of 6.87 × 10^?7 S/cm was obtained in the PC/PBT–MWCNT nanocomposites at an MWCNT loading as low as about 0.35 wt %. Transmission electron microscopy revealed a regular and homogeneous dispersion and distribution of the MWCNTs and formed a continuous conductive network pathway of MWCNTs throughout the matrix phase. The storage modulus and thermal stability of the PC were also enhanced by the presence of a small amount of MWCNTs in the nanocomposites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The role of a biobased epoxy monomer in the preparation of diglycidyl ether of bisphenol A/MWCNT composites

A biobased epoxy monomer (GA‐II) derived from gallic acid for multiwalls carbon nanotubes’ (MWCNTs) dispersion improvement is reported in this article. The aromatic group in its molecular structure made it to be absorbed onto the surface of MWCNTs via π‐π interactions and the GA‐II anchored MWCNT could be homogeneously dispersed in DGEBA matrix via sonication. That was proved by Raman and UV spectroscopy as well as scanning electron microscope. After curing reaction, the epoxy/MWCNT composites demonstrated enhanced mechanical properties, excellent thermal conductivity, and high electrical conductivity. With the addition of only 0.5 wt% GA‐II modified MWCNT, the tensile strength, tensile modulus, flexural strength, and flexural modulus of the composites were improved by 28%, 40%, 22%, and 16%, respectively. The thermal and electrical conductivities were also improved from 0.15 to 0.25 W/m K (67% increased) and from 0.7 × 10⁻¹⁴ to 0.24 × 10⁻⁴ S cm⁻¹ (10 orders increased). POLYM. COMPOS., 38:1640–1645, 2017. © 2015 Society of Plastics Engineers     

Microstructural characterization of corn starch‐based porous thermoplastic composites filled with multiwalled carbon nanotubes

Microstructural characterization of corn starch‐based porous thermoplastic (TPS) composites containing various contents (0.1, 0.5, and 1 wt %) of multiwalled carbon nanotubes (MWCNTs) was performed. Corn starch was plasticized with a proper combination of glycerol and stearic acid. TPS composites with MWCNT were prepared conducting melt extrusion followed by injection molding. TPS containing 1 wt % of MWCNTs exhibited higher tensile strength and elastic modulus values than neat TPS. Moreover, TPS electrical conductivity was determined to increase with increasing content of MWCNTs. X‐ray diffraction measurements revealed that incorporation of MWCNTs increased the degree of TPS crsystallinity to some extent. Scanning electron microscopy examination revealed that MWCNT altered TPS surface morphology and tensile failure modes, significantly. Transmission electron microscopy investigation showed that dispersion characteristics of MWCNTs within TPS were in the form of tiny clusters around micro pores of TPS, which is considered influential on electrical conductivity of the resulting composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013