Analysis of tensile modulus of PP/nanoclay/CaCO3 ternary nanocomposite using composite theories

The tensile modulus of PP/nanoclay/CaCO₃ hybrid ternary nanocomposite was analyzed using composite models. Rule of mixtures, inverse rule of mixtures, modified rule of mixtures (MROM), Guth, Paul, Counto, Hirsch, Halpin–Tsai, Takayanagi, and Kerner–Nielsen models were developed for three‐phase system containing two nanofillers. Among the studied models, inverse rule of mixtures, Hirsch, Halpin–Tsai, and Kerner–Nielsen models calculated the tensile modulus of PP/nanoclay/CaCO₃ ternary nanocomposite successfully compared with others. Furthermore, the Kerner–Nielsen model was simplified to predict the tensile modulus by volume fractions of nanofillers. Also, Takayanagi model was modified for the current ternary system. The developed Takayanagi model can predict the tensile modulus using Young's modulus and volume fractions of matrix and nanofillers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigation of rheological,mechanical, and thermal properties of nanocomposites based on nitrile rubber-phenolic resin reinforced with nanographene

In this study, nanocomposites of acrylonitrile butadiene rubber (NBR)/phenolic resin/graphene nanoparticles (GNPs) were prepared using a two-roll mill. According to the results, the addition of GNPs increased the scorch time, vulcanization time, and viscosity of the blends. By adding phenolic resin and in the presence of a higher percentage of acrylonitrile, the modulus and tensile strength increased and the elongation at break decreased. The mechanical properties of the nanocomposites improved with increasing the amount of nanoparticles. The addition of 1.5 phr GNP to the blends containing NBR with 33% and 45% acrylonitrile increased the tensile modulus by 56% and 49%, respectively. The tensile properties of the nanocomposites were also investigated at 50, 25, and 75°C. It was observed that with increasing the amount of nanoparticles, the deterioration of the mechanical properties at elevated temperatures was reduced. Also, thermal stability increased with increasing the amount of nanoparticles in all the samples.     

Synergistic effect of three‐dimensional multi‐walled carbon nanotube–graphene nanofiller in enhancing the mechanical and thermal properties of high‐performance silicone rubber

The homogeneous dispersion of nanofillers and filler–matrix interfacial interactions are important factors in the development of high‐performance polymer materials for various applications. In the present work, a simple solution‐mixing method was used to prepare multi‐walled carbon nanotube (MWCNT)–graphene (G) (3:1, 1:1, 1:3) hybrids followed by their characterization through wide‐angle X‐ray diffraction, transmission electron microscopy and thermogravimetric analyses. Subsequently, MWCNT–G (1:1) hybrid was used as reinforcing filler in the formation of silicone rubber (VMQ) nanocomposites by solution intercalation, and their morphology and properties were investigated. Our findings showed that MWCNT–G (0.75 wt%)/VMQ composite exhibited significant improvements in tensile strength (110%) and Young's modulus (137%) compared to neat VMQ. The thermal stability of MWCNT–G (1 wt%)/VMQ was maximally improved by 154 °C compared to neat VMQ. Differential scanning calorimetry demonstrated the maximum improvement of glass transition temperature (4 °C), crystallization temperature (8 °C) and melting temperature (5 °C) for MWCNT–G (1 wt%)/VMQ nanocomposite with respect to neat VMQ. Swelling measurements confirmed that the crosslink density and solvent resistance were a maximum for hybrid nanocomposites. Such improvements in the properties of MWCNT–G/VMQ nanocomposites could be attributed to a synergistic effect of the hybrid filler. © 2013 Society of Chemical Industry     

E‐beam‐cured layered‐silicate and spherical silica epoxy nanocomposites

This research demonstrates that an epoxy nanocomposite can be made through electron beam (e‐beam) curing. The nanofillers can be two‐dimensional (layered‐silicate) and zero‐dimensional (spherical silica). Both the spherical silica epoxy nanocomposite and the layered‐silicate epoxy nanocomposite can be cured to a high degree of curing. The transmission electron microscopy (TEM) and small‐angle X‐ray scattering of the e‐beam‐cured layered‐silicate epoxy nanocomposites demonstrate the intercalated nanostructure or combination of exfoliated and intercalated nanostructure. The TEM images show that the spherical silica epoxy nanocomposite has the morphology of homogeneous dispersion of aggregates of silica nanoparticles. The aggregate size is ～ 100 nm. The dynamic mechanical analysis shows that the storage modulus of the spherical silica nanocomposite has been improved, and the glass transition temperature can be very high (～ 175°C). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effects of amino‐functionalized carbon nanotubes on the properties of amine‐terminated butadiene–acrylonitrile rubber‐toughened epoxy resins

Amino‐functionalized multiwalled carbon nanotubes (MWCNT‐NH₂s) as nanofillers were incorporated into diglycidyl ether of bisphenol A (DGEBA) toughened with amine‐terminated butadiene–acrylonitrile (ATBN). The curing kinetics, glass‐transition temperature (T_g), thermal stability, mechanical properties, and morphology of DGEBA/ATBN/MWCNT‐NH₂ nanocomposites were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis, a universal test machine, and scanning electron microscopy. DSC dynamic kinetic studies showed that the addition of MWCNT‐NH₂s accelerated the curing reaction of the ATBN‐toughened epoxy resin. DSC results revealed that the T_g of the rubber‐toughened epoxy nanocomposites decreased nearly 10°C with 2 wt % MWCNT‐NH₂s. The thermogravimetric results show that the addition of MWCNT‐NH₂s enhanced the thermal stability of the ATBN‐toughened epoxy resin. The tensile strength, flexural strength, and flexural modulus of the DGEBA/ATBN/MWCNT‐NH₂ nanocomposites increased increasing MWCNT‐NH₂ contents, whereas the addition of the MWCNT‐NH₂s slightly decreased the elongation at break of the rubber‐toughened epoxy. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40472.     

Nano‐sio2‐reinforced ultraviolet‐curing materials for three‐dimensional printing

As an additive manufacturing technology, ultraviolet (UV)‐curing three‐dimensional printing, which requires the use of a photocurable resin, is increasingly being used to produce customized end‐user parts of many complex shapes. In this study, to improve the strength and ductility of printing materials, nano‐SiO₂‐reinforced photocurable resins were prepared by a planetary ball mill; then, the morphology, photochemistry, thermal property, and mechanical properties of the nanocomposites were investigated and characterized. Transmission electron microscopy analysis indicated that the modified nano‐SiO₂ was well dispersed in the photocurable resin. The glass‐transition temperature increased from 67.2°C for the unfilled resin to 71.7 and 80.1°C for nanocomposites with nano‐SiO₂ contents of 0.3 and 0.7 wt %, respectively. The tensile strength and impact strength were increased by 46.7 and 165.3% for nanocomposites with 0.3 wt % nano‐SiO₂. The flexural modulus of the nanocomposites increased from 1.7 to 8.0 GPa when 0.7 wt % nano‐SiO₂ was added to the photocurable resin; this appeared to originate from the relatively high level of dispersion and the intimate combination of the nano‐SiO₂ with the matrix. The investigation of the physical and chemical properties of such UV‐curing materials showed that the low filler concentration (<1 wt %) of nano‐SiO₂ did not affect the processability of the nanocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42307.     

Mechanical properties and multiscale characterization of nanofiber–alumina/epoxy nanocomposites

In contrast to the bulk of published nanocomposite studies, in this study we investigated the mechanical properties of alumina/epoxy nanocomposites manufactured with nanofillers having a fiber or whisker morphology. The article describes how ultrasonic dispersion and in situ polymerization were used to incorporate these 2–4 nm diameter fibers (with aspect ratios of 25–50) into a two‐part epoxy resin (Epon 826/Epicure 9551). The use of untreated and surface‐modified nanoparticles is contrasted, and improvements in both the tensile strength and modulus were observed at low filler loadings. Microstructural characterization of the nanocomposites via multiscale digital image analysis was used to interpret the mechanical properties and was found to be useful for direct comparison with other nanocomposites. In addition, superior performance was demonstrated through comparisons with numerous nanocomposites with nanoparticle reinforcements ranging from carbon nanofibers to spherical alumina particles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effects of silica nanoparticles on tribology performance of poly(Epoxy Resin‐Bismaleimide)‐based nanocomposites

Introduction of small nanoparticles into polymer matrix increases the mechanical, tribological, and thermal properties of nanocomposites. In this study, poly(epoxy resin‐bismaleimide‐diaminodiphenylmethane) (EP‐BMI‐DDM) copolymers filled with silica nanoparticles (SNPs) were successfully fabricated through in situ suspension polymerization. To enhance the interfacial adhesion of silica particles to the polymer matrix, the nanoparticles were organo‐modified by silane coupling agent. Results of tensile strength test revealed that increased toughness of the composites was attributed to the microcavitations induced by organo‐modified SNPs (OSNPs). Proper loadings of OSNPs can play a critical role in antifriction performance, with optimal friction coefficient of 0.17 (2 wt% OSNPs content). Thermostabilities of the nanocomposites were characterized by differential thermal gravimetric analysis. At the maximum rate of weight loss of EP‐BMI‐DDM/3 wt% OSNP, the temperature measured 452°C, which is 52°C higher than that of pure EP‐BMI‐DDM copolymers (400°C). The produced nanocomposites feature good thermostability and self‐lubrication can be widely used as wearable material under severe working conditions with higher temperature. POLYM. ENG. SCI., 59:274–283, 2019. © 2018 Society of Plastics Engineers     

UV‐curing and mechanical properties of polyester–acrylate nanocomposites films with silane‐modified antimony doped tin oxide nanoparticles

Antimony doped tin oxide (ATO) nanoparticles were used as nanofillers to improve mechanical properties of UV‐cured polyester–acrylate films. To improve the dispersion of ATO nanoparticles in the polyester–acrylate resin matrix and to strengthen interfacial interactions between ATO nanoparticles and the resin matrix ATO nanoparticles were first organically modified with 3‐methacryloxypropyltrimethoxysilane (MPS). The modification of ATO nanoparticles with MPS was confirmed by FTIR spectroscopy and thermogravimetric analysis (TGA). UV‐curing behaviors of the nanocomposites films were investigated by FTIR spectroscopy. Compared with the film with neat ATO nanoparticles, the film with the same amount of MPS‐modified ATO nanoparticles showed slightly higher UV‐curing rate and final conversion. The mechanical properties of the nanocomposites films were measured by universal testing machine. The MPS‐modified ATO nanoparticles could improve considerably the mechanical properties of the UV‐cured polyester–acrylate nanocomposites films. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Tensile modulus modeling of carbon‐filled liquid crystal polymer composites

Electrically and thermally conductive resins can be produced by adding conductive fillers to insulating polymers. Mechanical properties, such as tensile modulus, are also important. This research focused on performing compounding runs followed by injection molding and tensile testing of carbon‐filled Vectra liquid crystal polymer. The two carbon fillers investigated were Thermocarb synthetic graphite particles and Fortafil carbon fiber at varying filler amounts. The tensile modulus experimental results were compared to results predicted by several different models. It was found that the Halpin Tsai 2D Randomly Oriented fiber model provided the best fit to the experimental data. The degree of filler‐polymer adhesion was also studied with nanoscratch tests for synthetic graphite and carbon fiber fillers in three polymers: Vectra, nylon 6,6, and polycarbonate. The adhesion trends seen in the nanoscratch tests showed qualitative agreement with the tensile modulus, and should be considered in formulating advanced tensile modulus models. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Structure and properties of nanocomposites prepared by directly melt blending ethylene‐co‐vinylacetate and natural montmorillonite

The poly(ethylene‐co‐vinylacetate)/montmorillonite (EVA/MMT) nanocomposites were prepared by directly melt blending EVA and natural MMT in the presence of hexadecyl trimethylammonium bromide. The interlayer spacing of the silicate layers in EVA/MMT nanocomposites increased within 15 min of the blending time, and then remained unchanged with further increase in the blending time. The tensile and tear strength and Young's modulus of EVA/MMT nanocomposites increased with increasing blending time and reached the maximum value at 15 min, and then decreased. The tensile and tear strength and Young's modulus of EVA/MMT nanocomposites blended at 140°C were lower than those of the nanocomposites blended at 120°C. The thermal stability of EVA/MMT nanocomposites was improved compared with EVA. Furthermore, the thermal stability of EVA/MMT nanocomposites in nitrogen was higher than thermal stability of the nanocomposites in air because of the air destabilized the EVA and speeded up both deacylation and degradation. POLYM. COMPOS., 27:529–532, 2006. © 2006 Society of Plastics Engineers     

Physicomechanical properties of α‐cellulose–filled styrene–butadiene rubber composites

In this research, the influence of adding α‐cellulose powder to styrene–butadiene rubber (SBR) compounds was investigated. Physicomechanical properties of SBR–α‐cellulose composites, including tensile strength, elongation, Young's modulus, tear strength, hardness, abrasion, resilience, and compression set, before and after ageing, were determined and analyzed. Young's modulus, hardness, and compression set increased and elongation and resilience decreased with increasing α‐cellulose loading in the composites, whereas tensile strength, tear strength, and abrasion resistance initially increased at low α‐cellulose concentration (5 phr), after which these properties decreased with increasing α‐cellulose content. Lower loadings of α‐cellulose (5 phr) showed better results than higher loadings, given that tensile strength, tear strength, and abrasion resistance increased at low α‐cellulose concentration. Theoretical prediction of elastic modulus was carried out using rule of mixtures, Hashin, Kerner, and Halpin–Tsai equations. Calculated results show that these equations are not suitable for accurate prediction for the work carried out. However, these models can be used with confidence for the prediction of elastic modulus because experimental results are higher than the calculated values. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2203–2211, 2005     

Analysis of the dielectric spectroscopy of an epoxy‐ZnO nanocomposite using the universal relaxation law

There is currently no unified theory that explains the role of nanofillers in polymeric insulation. Consequently, different methods such as dielectric spectroscopy analysis are used to understand this role. The existence of a strong interaction between nanoparticles and a polymer is widely accepted. However, the interaction between dipoles has been taken into consideration in Jonscher's Universal Relaxation Law (URL) but not in the Debye theory. Hence, the URL was used in this article as a method to analyze the spectra of epoxy‐ZnO nanocomposites and to try to determine the nanoeffect mechanism. At 160°C above T_g (116°C), the typical phenomenon of low‐frequency dispersion occurs in the epoxy‐ZnO nanocomposites, and with filler loading increased up to 5 wt %, the value of n (calculated from the ε_r″ spectrum of the nanocomposites) increases both at high and low frequencies. This result indicates that higher loadings correspond to lower dielectric losses changing per radian. Moreover, the decrease in quasi‐direction conduction indicates that the gross dielectric losses of the nanocomposites are also less than pure epoxy resin (EP) at low frequencies. This finding may be attributed to the strong bonding between the nanofillers and the EP, which limits the movement of some macromolecular chains. The URL provides an analytical method for determining the mechanism of the effect of nanofillers on polymers. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites: Preparation and properties

4,4′‐Bismaleimidodiphenyl methane modified novolak resin/titania nanocomposites were prepared by the sol–gel process of tetrabutyl titanate in the presence of 4,4′‐bismaleimidodiphenyl methane modified novolak resin prepolymers with acetyl acetone as a stabilizer. These nanocomposite materials were characterized by Fourier transform infrared analysis, dynamical mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and field emission scanning electron microscopy. Nanometer titania particles were formed in the novolak resin matrix, and the average original particle size of the dispersed phase in the nanocomposites was less than 150 nm, but particle aggregates of larger size existed. The introduction of the titania inorganic phase with a nanoscale domain size did not improve the glass‐transition temperature of the nanocomposites but lowered the thermal resistance of the material because of the incomplete removal of acetyl acetone coordinated with tetrabutyl titanate, and it improved the modulus of the material at lower temperatures (<200°C) but lowered the modulus at higher temperatures (>250°C). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 52–57, 2006     

Thermomechanical and optical properties of biodegradable poly(L‐lactide)/silica nanocomposites by melt compounding

Poly(L ‐lactide) (PLA)/silica (SiO₂) nanocomposites containing 1, 3, 5, 7, and 10 wt % SiO₂ nanoparticles were prepared by melt compounding in a Haake mixer. The phase morphology, thermomechanical properties, and optical transparency were investigated and compared to those of neat PLA. Scanning electron microscopy results show that the SiO₂ nanoparticles were uniformly distributed in the PLA matrix for filler contents below 5 wt %, whereas some aggregates were detected with further increasing filler concentration. Differential scanning calorimetry analysis revealed that the addition of SiO₂ nanoparticles not only remarkably accelerated the crystallization speed but also largely improved the crystallinity of PLA. An initial increase followed by a decrease with higher filler loadings for the storage modulus and glass‐transition temperature were observed according to dynamic mechanical analysis results. Hydrogen bonding interaction involving C?O of PLA with Si? OH of SiO₂ was evidenced by Fourier transform infrared analysis for the first time. From the mechanical tests, we found that the tensile strength and modulus values of the nanocomposites were greatly enhanced by the incorporation of inorganic SiO₂ nanoparticles, and the elongation at break and impact strength were slightly improved. The optical transparency of the nanocomposites was excellent, and it seemed independent of the SiO₂ concentration; this was mainly attributed to the closed refractive indices between the PLA matrix and nanofillers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Enhanced coating properties of Ni‐La‐ferrites/epoxy resin nanocomposites

Coating properties of new Ni‐La‐ferrites/epoxy resin nanocomposites has been achieved using modified epoxy resin with Ni‐La‐ferrite nanoparticles in the form of NiLaFeO₄/epoxy nanocomposites using electrochemical impedance and sorption of water measurements. Simple solution method with ultrasonic assistance was used in the preparation of the new nanocomposites in situ while epoxy resin was prepared. The new materials were characterized by X‐ray diffraction analysis, thermogravimetric analysis, scanning electron microscopy, and electrochemical impedance spectroscopy. The nanocrystalline NiLaFeO₄ showed a good distribution and high compatibility forming strong interfacial adhesion within the epoxy matrix. Furthermore, it had ability to facilitate thermal degradation of the epoxy resin nanocomposite due to its catalytic effect. Temperatures at 10, 25, 50% weight loss and the normalized solid residue left at 500°C (NR500) were measured. The presence of nanocrystalline NiLaFeO₄ stabilized the char residue obtained at 500°C in the resulting composites. The Ni‐La‐ferrite nanoparticles decreased water sorption (WS) of the epoxy. The 5% and 10%‐ Ni‐La‐ferrites/epoxy nanocomposites showed least amount of WS among the epoxy composites. The 5 and 10% Ni‐La‐ferrite nanoparticles contents enhanced significantly the barrier behavior of the epoxy as coating of stainless steel. POLYM. COMPOS., 36:1875–1883, 2015. © 2014 Society of Plastics Engineers     

Thermal conductivity and dynamic mechanical property of glycidyl methacrylate‐grafted multiwalled carbon nanotube/epoxy composites

The well dispersed multiwalled carbon nanotube (MWCNT)/epoxy composites were prepared by functionalization of the MWCNT surfaces with glycidyl methacrylate (GMA). The morphology and thermal properties of the epoxy nanocomposites were investigated and compared with the surface characteristics of MWCNTs. GMA‐grafted MWCNTs improved the dispersion and interfacial adhesion in epoxy resin, and enhanced the network structure. The storage modulus of 3 phr GMA‐MWCNTs/epoxy composites at 50°C increased from 0.32 GPa to 2.87 GPa (enhanced by 799%) and the increased tanδ from 50.5°C to 61.7°C (increased by 11.2°C) comparing with neat epoxy resin, respectively. Furthermore, the thermal conductivity of 3 phr GMA‐MWCNTs/epoxy composite is increased by 183%, from 0.2042 W/mK (neat epoxy) to 0.5781 W/mK. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and characterization of modified‐clay‐reinforced and toughened epoxy‐resin nanocomposites

Epoxy–clay nanocomposites were prepared by the dispersion of an organically modified layered clay in an epoxy resin (diglycidyl ether of bisphenol A) and curing in the presence of methyl tetrahydro acid anhydride at 80–160°C. The nanometer‐scale dispersion of layered clay within the crosslinked epoxy‐resin matrix was confirmed by X‐ray diffraction and transmission electron microscopy, and the basal spacing of the silicate layer was greater than 100–150 Å. Experiments indicated that the hydroxyethyl groups of the alkyl ammonium ions, which were located in the galleries of organically modified clay, participated in the curing reaction and were directly linked to the epoxy‐resin matrix network. Experimental results showed that the properties of epoxy were improved, evidently because of the loading of organically modified clay. The impact strength and tensile strength of the nanocomposites increased by 87.8 and 20.9%, respectively, when 3 wt % organic clay was loaded, and this demonstrated that the composites were toughened and strengthened. The thermal‐decomposition and heat‐distortion temperatures were heightened in comparison with those of pure epoxy resin, and so were the dynamic mechanical properties, including the storage modulus and glass‐transition temperature. Moreover, experiments showed that most properties of the composites were ameliorated with low clay contents. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2649–2652, 2004     

Effects of an aminosilane and a tetra‐functional epoxy on the physical properties of di‐functional epoxy/graphene nanoplatelets nanocomposites

The physical properties of difunctional epoxies would be improved by adding nanofillers and multifunctional epoxies. Therefore, in this study, a tetrafunctional epoxy was added to difunctional epoxy/GNPs nanocomposites. An aminosilane was used to improve the interfacial bonding between GNPs and the epoxy matrix. The physical properties of the epoxy/GNPs nanocomposites were investigated by DSC, TMA, DMA, and electrical resistivity test. The glass transition temperature and storage modulus of the nanocomposites increased with increasing GNPs content. Adding the aminosilane resulted in a marginal increase in the glass transition temperature of the nanocomposites. However, adding the tetrafunctional epoxy resulted in a considerable increase in the glass transition temperature, thermal dimensional stability, and storage modulus of the nanocomposites. SEM images of the fracture surfaces of the nanocomposites showed that the aminosilane improved the interfacial bonding. The aminosilane and tetrafunctional epoxy made the sheet resistance of the nanocomposites higher. The sheet resistance data showed electrical percolation at 1–2 phr of GNPs. POLYM. ENG. SCI., 54:969–976, 2014. © 2013 Society of Plastics Engineers     

Preparation and properties of nano‐CaCO3/acrylonitrile‐butadiene‐styrene composites

CaCO₃/acrylonitrile‐butadiene‐styrene (ABS) and CaCO₃/ethylene‐vinyl acetate copolymer (EVA)/ABS nanocomposites were prepared by melting‐blend with a single‐screw extruder. Mechanical properties of the nanocomposites and the dispersion state of CaCO₃ particles in ABS matrix were investigated. The results showed that in CaCO₃/EVA/ABS nanocomposites, CaCO₃ nanoparticles could increase flexural modulus of the composites and maintain or increase their impact strength for a certain nano‐CaCO₃ loading range. The tensile strength of the nanocomposites, however, was appreciably decreased by adding CaCO₃ nanoparticles. The microstructure of neat ABS, CaCO₃/ABS nanocomposites, and CaCO₃/EVA/ABS nanocomposites was observed by scanning electron microscopy. It can be found that CaCO₃ nanoparticles were well‐dispersed in ABS matrix at nanoscale. The morphology of the fracture surfaces of the nanocomposites revealed that when CaCO₃/EVA/ABS nanocomposites were exposed to external force, nano‐CaCO₃ particles initiated and terminated crazing (silver streak), which can absorb more impact energy than neat ABS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008