Preparation and properties of new EPDM/vermiculite nanocomposites

Novel nanocomposites based on ethylene‐propylene‐diene rubber (EPDM) and maleic anhydride‐modified vermiculite (VMT) were prepared. Maleic anhydride (MA) acts both as the intercalation agent for VMT and as a vulcanizing agent for EPDM matrix. It also acts as a compatibilizer for EPDM and VMT phases. From analysis by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the silicate layers of the VMT were exfoliated and dispersed uniformly in the EPDM matrix as monolayers. The thermal properties of the nanocomposites were investigated by dynamic mechanical thermal analysis and thermogravimetric analysis; a strong rubber‐filler interaction in the nanocomposites was manifested in the measured temperature range by the result of storage modulus. At the same time, there was some enhancement in degradation behavior between the nanocomposites and EPDM matrix. The nanocomposites exhibited a great improvement in tensile strength and modulus, as well as elongation at break. Finally, the effects of MA addition on the formation of nanometric reinforcement and on the mechanical properties of nanocomposites are discussed. POLYM. COMPOS., 26:706–712, 2005. © 2005 Society of Plastics Engineers     

Effect of montmorillonoite modification and maleic anhydride‐grafted polypropylene on the microstructure and mechanical properties of polypropylene/montmorillonoite nanocomposites

Two types of modified montmorillonite (MMT) were achieved using octadecylamine as the modifying agent by the methods of dry process and wet route. Polypropylene (PP)/MMT nanocomposites were prepared using the melt mixing technique and employing maleic anhydride‐grafted polypropylene (PP‐MA) as the compatibilizer. The modification of montmorillonite was characterized by fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and scanning electron microscope (SEM). The effect of MMT modification and PP‐MA on the microstructure and properties of PP/MMT nanocomposites was investigated by SEM, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and polarizing microscopy. The results show that organic montmorillonite modified by wet process (WOMMT) has a large d‐spacing increment; whereas montmorillonite modified by dry process (DOMMT) shows little d‐spacing increment. Furthermore, the mechanical properties of composites incorporating WOMMT are better than that containing DOMMT. As a third component, the addition of PP‐MA benefits the formation of exfoliated structure and the dispersion of MMT in PP matrix, and hence, enhances the physical properties of the nanocomposite. With the presence of PP‐MA, the highly dispersed MMT increases the number of spherulite crystals, enhances the melting enthalpy, improves the thermal stability, and induces the desired tiny crazes more effectively. MMT increases the storage modulus (E′) and glass‐transition temperature (T_g) of PP because of the stiffness of MMT layers, but PP‐MA decreases them owing to its high melt flow index, both of which were in favor of improving the physical properties. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3952–3960, 2013     

Combination of double‐modified clay and polypropylene‐graft‐maleic anhydride for the simultaneously improved thermal and mechanical properties of polypropylene

Double‐modified montmorillonite (MMT) was first prepared by covalent modification of MMT with 3‐aminopropyltriethoxysilane and then intercalation modification by tributyl tetradecyl phosphonium ions. The obtained double‐modified MMT was melt compounded with polypropylene (PP) to obtain nanocomposites. The dispersion of the double‐modified MMT in PP was found to be greatly improved by the addition of PP‐graft‐maleic anhydride (PP‐g‐MA) as a “compatibilizer,” whose anhydride groups can react with the amino groups on the surface of the double‐modified MMT platelets and thus improve the dispersion of MMT in PP. Fourier transform infrared, X‐ray diffraction, transmission electron microscopy, thermogravimetric analysis, scanning electron microscopy, and tensile test were used to characterize the structure of the double‐modified MMT, morphology, and the thermal and mechanical properties of the nanocomposites. The results show that PP‐g‐MA promotes the formation of exfoliated/intercalated morphology and obviously increases the thermal properties, tensile strength, and Young's modulus of the PP/double‐modified MMT nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and evaluation of high‐performance ethylene–propylene–diene terpolymer/organoclay nanoscale composites

The main objective of this study was to synthesize and characterize the properties of ethylene–propylene–diene terpolymer (EPDM)/clay nanocomposites. Pristine clay, sodium montmorillonite (Na⁺–MMT), was intercalated with hexadecyl ammonium ion to form modified organoclay (16Me–MMT) and the effect of intercalation toward the change in interlayer spacing of the silicate layers was studied by X‐ray diffraction, which showed that the increase in interlayer spacing in Na⁺–MMT by 0.61 nm is attributed to the intercalation of hexadecyl ammonium ion within the clay layers. In the case of EPDM/16Me–MMT nanocomposites, the basal reflection peak was shifted toward a higher angle. However, gallery height remained more or less the same for different EPDM nanocomposites with organoclay content up to 8 wt %. The nanostructure of EPDM/clay composites was characterized by transmission electron microscopy, which established the coexistence of intercalated and exfoliated clay layers with an average layer thickness in the nanometer range within the EPDM matrix. The significant improvement in thermal stability and mechanical properties reflects the high‐performance nanocomposite formation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2429–2436, 2004     

Exfoliation targeted toughness enhancement in polypropylene‐blend‐ montmorillonite nanocomposites

BACKGROUND: Both exfoliated and toughened polypropylene‐blend‐montmorillonite (PP/MMT) nanocomposites were prepared by melt extrusion in a twin‐screw extruder. Special attention was paid to the enhancement of clay exfoliation and toughness properties of PP by the introduction of a rubber in the form of compatibilizer toughener: ethylene propylene diene‐based rubber grafted with maleic anhydride (EPDM‐g‐MA). RESULTS: The resultant nanocomposites were characterized using X‐ray diffraction, atomic force microscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis and Izod impact testing methods. It was found that the desired exfoliated nanocomposite structure could be achieved for all compatibilizer to organoclay ratios as well as clay loadings. Moreover, a mechanism involving a decreased size of rubber domains surrounded with nanolayers as well as exfoliation of the nanolayers in the PP matrix was found to be responsible for a dramatic increase in impact resistance of the nanocomposites. CONCLUSION: Improved thermal and dynamic mechanical properties of the resultant nanocomposites promise to open the way for highly toughened super PPs via nanocomposite assemblies even with very low degrees of loading. Copyright © 2008 Society of Chemical Industry     

Mechanical and dynamic mechanical properties of nylon 66/montmorillonite nanocomposites fabricated by melt compounding

Nylon 66 nanocomposites were prepared by melt compounding of nylon 66 with organically modified montmorillonite (MMT). The organic MMT was pre‐modified with about 14 wt% of ammonium surfactant, much lower than the 35–46 wt% in most commercial organic MMT powders. Transmission electron microscope observation indicated that the MMT layers were well exfoliated in nylon 66 matrix. Dynamic mechanical analysis confirmed the constraint effect of exfoliated MMT layers on nylon 66 chains, which benefited the increased storage modulus, increased glass transition temperature and reduced magnitude of alpha relaxation peak. The effects of organic MMT loading levels on reinforcement and fracture behaviour of the nanocomposites were evaluated using tensile and three‐point bending tests. The addition of the organic MMT clearly increased Young's modulus and tensile strength but decreased ductility and fracture toughness of nylon 66. Copyright © 2004 Society of Chemical Industry     

Ethylene propylene diene terpolymer/ethylene vinyl acetate/layered silicate ternary nanocomposite by solution method

A new ternary nanocomposite has been developed using ethylene propylene diene terpolymer (EPDM), ethylene vinyl acetate (EVA‐45) copolymer, and organically modified layered silicate (16 Me‐MMT) from sodium montmorillonite (Na⁺‐MMT). Wide angle X‐ray diffraction and transmission electron microscopic analysis confirmed the intercalation of the polymer chains in between the organosilicate layers and the nanoscale distribution of 16 Me‐MMT in polymer matrix, respectively. The measurement of mechanical properties for 2–8 wt% of 16 Me‐MMT loadings showed a significant increase in tensile strength, elongation at break, and modulus at different elongations. Such an improvement in mechanical properties has been correlated based on the fracture behavior of nanocomposite by SEM analysis. Thermal stability of EPDM/EVA/layered silicate ternary nanocomposites also showed substantial improvements compared with the neat EPDM/EVA blend, confirming thereby the formation of a high performance nanocomposite. POLYM. ENG. SCI., 46:437–843, 2006. © 2006 Society of Plastics Engineers     

Synthesis and properties of poly(ester ether) multiblock copolymers/organomontmorillonite hybrid nanocomposite

In this article, poly(ester ether) multiblock copolymer/organomontmorillonite hybrid nanocomposites were prepared via an intercalation polymerization process. The resulting hybrid nanocomposites were characterized by X‐ray diffraction, differential scanning calorimeter, and transmission electron microscopy. The results proved that the organomontmorillonite (organo‐MMT) could be exfoliated into ～ 50‐nm thickness and dispersed in the poly(ester ether) multiblock copolymer (TPEE) matrix during the intercalation polymerization process. TPEE/organo‐MMT nanocomposites showed excellent mechanical properties compared with the unfilled TPEE. When the organo‐MMT content was about 3–5 wt %, MMT could enhance the strength, modulus, and hardness of TPEE without sacrificing its elongation at break. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1716–1720, 2002; DOI 10.1002/app.10552     

Organomodification of montmorillonite and its effects on the properties of poly(butylene succinate) nanocomposites

The pristine sodium montmorillonite (MMT) was organically modified with hexadecyltrimethylammonium bromide (HTAB) at different contents. The organoclay was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy, energy dispersive X‐ray techniques, and thermogravimetric analysis. Then, poly(butylene succinate) (PBS) nanocomposites were prepared by melt‐mixing process using maleic anhydride‐grafted PBS (PBS‐g‐MA) as compatibilizer. It was found that the mechanical properties of PBS nanocomposites filled with organoclay were apparently higher than that of the nanocomposite filled with MMT. This is attributed to the better filler–matrix interactions between PBS and the organoclay and the better filler dispersion. This is verifiable through the XRD, scanning electron microscopy, and transmission electron microscopy. The addition of PBS‐g‐MA further improved the mechanical properties. It was also found that our laboratory synthesized organoclay modified with HTAB has provided a better reinforcing efficiency when compared with the commercial octadecylamine‐modified organoclay. Besides that the thermal properties of PBS nanocomposites were studied through differential scanning calorimetry. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

Preparation and properties of EPDM/organomontmorillonite hybrid nanocomposites

Hybrid nanocomposites based on organophillic montmorillonite (MMT) and ethylene–propylene–diene rubber (EPDM) have been prepared by a melt compounding process. From analysis by X‐ray diffraction and transmission electron microscopy, the rubber molecules were found to be intercalated into the galleries of organoMMT and the silicate layers of organoMMT are uniformly dispersed as platelets of 50–80 nm thickness in the EPDM matrix. Dynamic mechanical studies reveal a strong rubber–filler interaction in the hybrid nanocomposite which is manifested in the lowering of tan δ at the glass transition temperature. The hybrid nanocomposites exhibit great improvement in tensile and tear strength, and modulus, as well as elongation‐at‐break. Moreover, the permeability of oxygen for the hybrid nanocomposite was reduced remarkably. © 2002 Society of Chemical Industry     

Ethylene vinyl acetate/ethylene propylene diene terpolymer‐blend‐layered double hydroxide nanocomposites

Ethylene vinyl acetate (EVA‐45)/ethylene propylene diene terpolymer (EPDM) blend‐layered double hydroxide (LDH) nanocomposites have been prepared by solution blending of 1:1 weight ratio of EVA and EPDM with varying amounts of organo LDH (DS‐LDH). X‐ray diffraction and transmission electron microscopy analysis suggest the formation of partially exfoliated EVA/EPDM/DS‐LDH nanocomposites. Measurement of mechanical properties of the nanocomposites (3 wt% DS‐LDH content) show that the improvement in tensile strength and elongation at break are 35 and 12% higher than neat EVA/EPDM blends. Dynamic mechanical thermal analysis also shows that the storage modulus of the nanocomposites at glass transition temperature is higher compared to the pure blend. Such improvements in mechanical properties have been correlated in terms of fracture behavior of the nanocomposites using scanning electron microscopy analysis. Thermal stability of the prepared nanocomposites is substantially higher compared to neat EVA/EPDM blend, confirming the formation of high‐performance polymer nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Bio‐based polymer nanocomposites based on layered silicates having a reactive and renewable intercalant

Soybean oil‐based polymer nanocomposites were synthesized from acrylated epoxidized soybean oil (AESO) combined with styrene monomer and montmorillonite (MMT) clay by using in situ free radical polymerization reaction. Special attention was paid to the modification of MMT clay, which was carried out by methacryl‐functionalized and quaternized derivative of methyl oleate intercalant. It was synthesized from olive oil triglyceride, as a renewable intercalant. The resultant nanocomposites were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The effect of increased nanofiller loading in thermal and mechanical properties of the nanocomposites was investigated by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The nanocomposites exhibited improved thermal and dynamic mechanical properties compared with neat acrylated epoxidized soybean oil based polymer matrix. The desired exfoliated nanocomposite structure was achieved when the OrgMMT loading was 1 and 2 wt % whereas partially exfoliated nanocomposite was obtained in 3 wt % loading. It was found that about 400 and 500% increments in storage modulus at glass transition and rubbery regions, respectively were achieved at 2 wt % clay loading compared to neat polymer matrix while the lowest thermal degradation rate was gained by introducing 3 wt % clay loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2031–2041, 2013     

Effect of oligomeric‐modified montmorillonite on morphology and properties of polycarbonate/montmorillonite nanocomposites

Low‐molecular‐weight copolymers of styrene and vinylbenzyl ammonium salts (oligomeric surfactant) were used to modify montmorillonite (MMT). The oligomeric‐modified MMT showed good thermal stability, which made it suitable to be used for preparing polycarbonate(PC)/MMT nanocomposites at high temperature. A different series of PC/MMT nanocomposites had been prepared by melt processing using a twin screw extruder. The effect of oligomeric surfactant structure and clay loading on the morphology, mechanical property, thermal stability, and color appearance of the nanocomposites were explored. The results of X‐ray diffraction and transmission electron microscopy analyses indicated that the PC/MMT nanocomposites had partially exfoliated structures. The PC/MMT nanocomposites were found to retain light colored, which was important for optical application. Compared to neat PC, the nanocomposites showed better properties of thermal stability and heat insulation. The mechanical properties of the nanocomposites are significantly enhanced by incorporating clay into the PC matrix. The tensile strength of nanocomposites with 2 wt% clay content was up to 55 MPa, which was much higher than that of the neat PC (37 MPa). The maximum tensile modulus value was 19% higher than that of neat PC. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

EPDM/silicone blend layered silicate nanocomposite by solution intercalation method: Morphology and properties

Ethylene–propylene–diene terpolymer (EPDM)/silicone blend nanocomposites are prepared by solution method for the first time. EPDM and silicone rubber in their 50:50 (by weight) blend is intercalated within the silicate sheets of organically modified montmorillonite. Organic modification to the pristine sodium montmorillonite (Na‐MMT) surfaces is carried out by ion‐exchange reaction using hexadecyl ammonium chloride. The incorporation of such organic functional group makes Na‐MMT hydrophobic and expands the interlayer spacing between silicate sheets. The intercalated structure of EPDM/silicone blend nanocomposites is characterized by the X‐ray diffraction. Transmission electron microscopic characterization visualized the presence of both exfoliated and intercalated layered silicate in the polymer nanocomposites. The mechanical properties of the nanocomposites show a maximum improvement in tensile strength and elongation at break of 23 and 68%, respectively, compared with EPDM/silicone blend. The dielectric measurement demonstrates the increase in relative permittivity for the nanocomposite than the pure blend. The increase in the onset temperature of the thermal degradation of nanocomposites (∼52°C) corresponding to 1 wt% decomposition indicates the enhancement of thermal stability of (EPDM)/silicone blend due to interaction with silicates. POLYM. COMPOS., 35:1834–1841, 2014. © 2014 Society of Plastics Engineers     

Effect of clay modification on the morphological,mechanical, and thermal properties of polyamide 6/polypropylene/montmorillonite nanocomposites

Polyamide 6/polypropylene (PA6/PP = 70/30 parts) blends containing 4 phr (parts per hundred resin) of organophilic montmorillonite (OMMT) were prepared by melt compounding. The sodium montmorillonite (Na‐MMT) was modified using three different types of alkyl ammonium salts, namely dodecylamine, 12‐aminolauric acid, and stearylamine. The effect of clay modification on the morphological and mechanical properties of PA6/PP nanocomposites was investigated using x‐ray diffraction (XRD), transmission electron microscopy (TEM), tensile, flexural, and impact tests. The thermal properties of PA6/PP nanocomposites were characterized using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and heat distortion temperature (HDT). XRD and TEM results indicated the formation of exfoliated structure for the PA6/PP nanocomposites prepared using stearylamine modified montmorillonite. On the other hand, a mixture of intercalated and exfoliated structures was found for the PA6/PP nanocomposites prepared using 12‐aminolauric acid and dodecylamine modified montmorillonite. Incorporation of OMMT increased the stiffness but decreased the ductility and toughness of PA6/PP blend. The PA6/PP nanocomposite containing stearylamine modified montmorillonite showed the highest tensile, flexural, and thermal properties among all nanocomposites. This could be attributed to better exfoliated structure in the PA6/PP nanocomposite containing stearylamine modified montmorillonite. The storage modulus and HDT of PA6/PP blend were increased significantly with the incorporation of both Na‐MMT and OMMT. The highest value in both storage modulus and HDT was found in the PA6/PP nanocomposite containing stearylamine modified montmorillonite due to its better exfoliated structure. POLYM. COMPOS., 31:1156–1167, 2010. © 2009 Society of Plastics Engineers     

Preparation and properties of polypropylene filled with organo‐montmorillonite nanocomposites

Organo‐Montmorillonite (Org‐MMT)/maleic anhydride grafted polypropylene (PP‐g‐MAH)/polypropylene nanocomposites have been prepared by melt blending with twin‐screw extruder. The mechanical properties of the nanocomposites and the dispersion of Org‐MMT intercalated by the macromolecular chain were investigated by transmission electron microscopy and mechanical tests. The crystal properties of the nanocomposites have been tested by a differential scanning calorimeter. The thermal properties of the nanocomposites were investigated by thermo gravimetric analysis. The results show that not only the impact property but also the tensile property and the bending modulus of the system have been increased evidently by the added Org‐MMT. The Org‐MMT has been dispersed in the matrix in the nanometer scale. With the addition of the Org‐MMT, the melting point and the crystalling point of the nanocomposites increased; the total velocity of crystallization of the nanocomposites also increased. Thermal stability of the nanocomposites is increased by the filled Org‐MMT. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2875–2880, 2006     

Preparation and characteristics of nitrile rubber (NBR) nanocomposites based on organophilic layered clay

The effect of clay modification on organo‐montmorillonite/NBR nanocomposites has been studied. Organo‐montmorillonite/NBR nanocomposites were prepared through a melt intercalation process. NBR nanocomposites were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and a universal testing machine (UTM). XRD showed that the basal spacing in the clay increased, which means that the NBR matrix was intercalated in the clay layer galleries. On TEM images, organo‐montmorillonite (MMT) particles were clearly observed, having been exfoliated into nanoscale layers of about 10–20 nm thickness from their original 40 µm particle size. These layers were uniformly dispersed in the NBR matrix. The DMTA test showed that for these nanocomposites the plateau modulus and glass transition temperature (T_g) increased with respect to the corresponding values of pure NBR (without clay). UTM test showed that the nanocomposites had superior mechanical properties, ie strength and modulus. These improved properties are due to the nanoscale effects and strong interactions between the NBR matrix and the clay interface. Copyright © 2003 Society of Chemical Industry     

Preparation and characterization of polystyrene–clay nanocomposites by free‐radical polymerization

The polymerizable cationic surfactant, vinylbenzyldimethylethanolammouium chloride (VBDEAC), was synthesized to functionalize montmorillonite (MMT) clay and used to prepare exfoliated polystyrene–clay nanocomposites. The organophilic MMT was prepared by Na⁺ exchanged montmorillonite and ammonium cations of the VBDEAC in an aqueous medium. Polystyrene–clay nanocomposites were prepared by free‐radical polymerization of the styrene containing intercalated organophilic MMT. Dispersion of the intercalated montmorillonite in the polystyrene matrix determined by X‐ray diffraction reveals that the basal spacing is higher than 17.6 nm. These nanocomposites were characterized by differential scanning calorimetry (DSC), transmission electron micrograph (TEM), thermal gravimetric analysis (TGA), and mechanical properties. The exfoliated nanocomposites have higher thermal stability and better mechanical properties than the pure polystyrene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1370–1377, 2002     

Poly(vinyl chloride)/metallic oxides/organically modified montmorillonite nanocomposites: Preparation,morphological characterization,and modeling of the mechanical properties

Poly(vinyl chloride), metallic oxides (from copper, molybdenum, and zinc), and organically modified montmorillonite (O‐MMT) nanocomposites were prepared in a melt‐blending or intercalation‐in‐the‐molten‐state process. The morphology of the nanocomposites was evaluated with X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Properties, such as the mechanical, thermal, and electrical properties, and the dynamic thermal stability against dehydrochlorination were also evaluated. Nanocomposites with a hybrid intercalated/exfoliated structure were obtained in all of the situations considered, as demonstrated by the XRD and TEM results and indirectly by the increment of Young's modulus of the formulations with increasing amount of O‐MMT incorporated. The modeling of Young's modulus by the Halpin–Tsai, Hui–Shia, and Lewis–Nielsen theories showed that the process of nanocomposite preparation allowed the aspect ratio of the clay particles to increase; these values were comparable to those nanocomposites obtained by other researchers with different polymeric matrices and methodologies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The effect of clay type and of clay–masterbatch product in the preparation of polypropylene/clay nanocomposites

Clay containing polypropylene (PP) nanocomposites were prepared by direct melt mixing in a twin screw extruder using different types of organo‐modified montmorillonite (Cloisite 15 and Cloisite 20) and two masterbatch products, one based on pre‐exfoliated clays (Nanofil SE 3000) and another one based on clay–polyolefin resin (Nanomax‐PP). Maleic anhydride‐grafted polypropylene (PP‐g‐MA) was used as a coupling agent to improve the dispersability of organo‐modified clays. The effect of clay type and clay–masterbatch product on the clay exfoliation and nanocomposite properties was investigated. The effect of PP‐g‐MA concentration was also considered. Composite morphologies were characterized by X‐ray diffraction (XRD), field emission gun scanning electron microscopy (FEG‐SEM), and transmission electron microscopy (TEM). The degree of dispersion of organo‐modified clay increased with the PP‐g‐MA content. The thermal and mechanical properties were not affected by organo‐modified clay type, although the masterbatch products did have a significant influence on thermal and mechanical properties of nanocomposites. Intercalation/exfoliation was not achieved in the Nanofil SE 3000 composite. This masterbatch product has intercalants, whose initial decomposition temperature is lower than the processing temperature (T ～ 180°C), indicating that their stability decreased during the process. The Nanomax‐PP composite showed higher thermal and flexural properties than pure PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011