Preparation and characterization of poly(butylene terephthalate) nanocomposites with various organoclays

Layered‐silicate‐based polymer–clay nanocomposite materials were prepared depending on the surface modification of montmorillonite (MMT). Nanocomposites consisting of poly(butylene terephthalate) (PBT) as a matrix and dispersed inorganic clay modified with cetyl pyridinium chloride (CPC), benzyl dimethyl N‐hexadecyl ammonium chloride, and hexadecyl trimethyl ammonium bromide by direct melt intercalation were studied. The organoclay loading was varied from 1 to 5 wt %. The organoclays were characterized with X‐ray diffraction (XRD) to compute the crystallographic spacing and with thermogravimetric analysis to study the thermal stability. Detailed investigations of the mechanical and thermal properties as well as a dispersion study by XRD of the PBT/clay nanocomposites were conducted. X‐ray scattering showed that the layers of organoclay were intercalated with intercalating agents. According to the results of a differential scanning calorimetry analysis, clay acted as a nucleating agent, affecting the crystallization. The PBT nanocomposites containing clay treated with CPC showed good mechanical properties because of intercalation into the polymer matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of organic modification on mechanical properties of melt processed intercalated poly(methyl methacrylate)–organoclay nanocomposites

The influence of organic modifiers on intercalation extent, structure, thermal and mechanical properties of poly(methyl methacrylate) (PMMA)–clay nanocomposites were studied. Two different organic modifiers with varying hydrophobicity (single tallow versus ditallow) were investigated. The nanocomposites were prepared from melt processing method and characterized using wide angle X‐ray diffraction, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), and tensile tests. Mechanical properties such as tensile modulus (E), break stress (σ_brk), and % break strain (ε_brk) were determined for nanocomposites at various clay loadings. Extent of PMMA intercalation is sufficient and in the range 9–15 Å depending on organoclay and filler loading. Overall thermal stability of nanocomposites increases by 16–30°C. The enhancement in T_g of nanocomposite is merely by 2–4°C. With increase in clay loading, tensile modulus increases linearly while % break strain decreases. Break stress is found to increase till 4 wt % and further decreases at higher clay loadings. The overall improvement in thermal and mechanical properties was higher for the organoclay containing organic modifier with lower hydrophobicity and single tallow amine chemical structure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of organoclay on the morphology,mechanical, thermal,and rheological properties of organophilic montmorillonite nanoclay based thermoplastic polyurethane nanocomposites prepared by melt blending

Polymer nanocomposites based on the thermoplastic polyurethane (TPU) and organically modified montmorillonite (OMMT) was prepared by melt intercalation technique using a laboratory internal batch mixer followed by compression molding. Varying amount of organically modified nanoclays (1, 3, 5, 7, and 9 wt%) was added to the TPU matrix to examine the influence of organoclay on nanophase morphology and structure–property relationships. The interaction between TPU matrix and nanofiller was studied by infrared spectroscopy. The morphology of nanocomposites was studied by X‐ray diffraction, transmission electron microscopy, and atomic force microscopy that shows melt mixing by a batch mixer is an effective method for dispersing OMMT throughout the TPU matrix. Thermogravimetric analysis revealed that incorporation of organoclay enhances the thermal stability of the nanocomposites significantly. Differential scanning calorimetry was employed to measure the melting point and glass transition temperature (T_g) of soft segments. The reinforcing effect of the organoclay was determined by dynamic mechanical analysis and physico–mechanical testing. The effects of nanoclay concentration and processing parameters on the dynamic viscoelastic properties of the nanocomposites were studied by a rubber process analyzer using frequency sweep. A significant increase in the viscosity and storage modulus of the nanocomposites was found with the increasing clay content. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Transparent copolyester/organoclay nanocomposites prepared by in situ intercalation polymerization: Synthesis,characterization, and properties

In this study, amorphous poly(ethylene terephthalate‐co‐1,3/1,4‐cyclohexylenedimethylene terephthalate) (PETG)/organoclay nanocomposites was synthesized by the in situ intercalation polymerization of terephthalic acid, ethylene glycol, 1,3/1,4‐cyclohexanedimethanol, and organoclay. The organoclay was obtained by modifying sodium montmorillonite (clay) with hexadecyl triphenylphosphonium bromide. The thermal, mechanical, optical, and gas barrier properties of these PETG nanocomposites with various organoclay contents (0–3 wt%) were discussed. The differential scanning calorimetry and X‐ray analyses revealed that all of the nanocomposites were amorphous. X‐ray diffraction and transmission electron micrographs showed that the organoclay was well dispersed in the polymer matrix, although some parts of the agglomerated layers remained on the scale of several hundreds of nanometers. The thermal stability and the mechanical property of the nanocomposites increased with organoclay content. The optical transmittances of nanocomposites that contained 0.5, 1, and 3 wt% of organoclay were 86.8%, 84.4%, and 77.4%, respectively. The oxygen transmission rate of the nanocomposite that contained 3 wt% of organoclay was about 50% of the PETG base polymer. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Experimental and computational investigation of EVOH/clay nanocomposites

Ethylene–vinyl alcohol copolymer (EVOH)/organoclay nanocomposites were prepared via a dynamic melt‐intercalation process. The effect of compatibilizers on the melt blending torque, intercalation level, and morphology of EVOH/organoclay systems was investigated. Maleic anhydride grafted ethylene vinyl acetate (EVA‐g‐ MA), or maleic anhydride grafted linear low‐density polyethylene (LLDPE‐g‐MA), were used to compatibilize EVOH with clay, at various concentrations (1, 5, and 10 wt %). Computer‐simulation techniques are used to predict structural properties and interactions of EVOH with compatibilizers in the presence and absence of clay. The simulation results strongly support the experimental findings and their interpretation. X‐ray diffraction shows enhanced intercalation within the galleries when the compatibilizers were added. Interestingly, results were obtained for the EVOH/clay/compatibilizer systems, owing to a high level of interaction developed in these systems. Thermal analysis shows that, upon increasing the compatibilizer content, lower crystallinity levels result, until at a certain compatibilizer content no crystallization is taking place. Significantly higher mixing viscosity levels were obtained for the EVOH/organoclay blends compared with the neat EVOH polymer. The storage modulus was higher compared with the uncompatibilized EVOH/organoclay blend in the presence of EVA‐g‐MA compatibilizer (at all concentrations), and only at low contents of LLDPE‐g‐MA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2060–2066, 2005     

Polystyrene–organoclay nanocomposites prepared by melt intercalation,in situ,and masterbatch methods

In this study, polystyrene (PS)/montmorillonite nanocomposites were prepared by melt intercalation, in situ polymerization, and masterbatch methods. In the masterbatch method, as the first step, a high clay content composite of PS–organoclay (masterbatch) was prepared by in situ polymerization, and then the prepared masterbatch was diluted to desired compositions with commercial PS in a twin‐screw extruder. The structure and mechanical properties of the nanocomposites were examined. X‐ray diffraction (XRD) analysis showed that the d‐spacing of the in situ formed nanocomposites increased from 32.9 Å for the organoclay powder to 36.3 and 36.8 Å respectively in nanocomposites containing 0.73 and 1.6 wt% organoclay, indicating intercalation. However, the d‐spacing of the other prepared materials remained nearly unchanged when compared with pure organoclay powder. Thus, at these low clay contents, in situ formed nanocomposites showed the best improvement in mechanical properties including tensile, impact strength, and Young's modulus. In situ polymerization method did not prove to be efficient at high clay loadings in terms of intercalation and mechanical properties. At high clay loadings, the effects of the three methods in promoting mechanical properties were not significantly different from each other. POLYM. COMPOS., 27:249–255, 2006. © 2006 Society of Plastics Engineers     

Preparation and characterization of poly(vinyl chloride)/organoclay nanocomposites by in situ intercalation

In this article, poly(vinyl chloride) (PVC)–organoclay nanocomposites were prepared via in situ polymerization intercalation and melt blending intercalation, respectively. Their nanostructures were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Differences in the morphologies of the PVC hybrids prepared by in situ intercalation and melt intercalation were investigated. In addition, three kinds of organoclay were used, in order to consider the effect of the interlayer environment on intercalation. The results show that ammonium cations have a great influence on the hybrids prepared by melt intercalation, while they have no obvious effect on the nanostructures of the composites produced via in situ intercalation due to its distinctive process and its mechanism. Copyright © 2004 Society of Chemical Industry     

Synthesis and characterization of poly(ethylene terephthalate) nanocomposites with organoclay

Poly(ethylene terephthalate) (PET)/montmorillonite (MMT) nanocomposites were prepared by solution intercalation method. The clay was organo‐modified with the intercalation agent cetylpyridinium chloride (CPC). Wide‐angle X‐ray diffraction (XRD) showed that the layers of MMT were intercalated by CPC. Four nanocomposites with organoclay contents of 1, 5, 10, and 15 wt % were prepared by solution blending. XRD showed that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay present. According to the results of differential scanning calorimetry (DSC) analysis, clay behaves as a nucleating agent and enhances the crystallization rate of PET. The maximum enhancement of crystallization rate for the nanocomposites was observed in those containing about 10 wt % organoclay within the studied range of 1–15 wt %. From thermogravimetric analysis (TGA), we found that the thermal stability of the nanocomposites was enhanced by the addition of 1–15 wt % organoclay. These nanocomposites showed high levels of dispersion without agglomeration of particles at low organoclay content (5 wt %). An agglomerated structure did form in the PET matrix at 15 wt % organoclay. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 140–145, 2004     

Preparation and characterization of polyurethane–organoclay nanocomposites

Nanocomposite polyurethane (PU)–organoclay materials have been synthesized via in‐situ polymerization. The organoclay is first prepared by intercalation of tyramine into montmorillonite (MMT)‐clay through ion exchange process. The syntheses of polyurethane–organoclay hybrid films containing different ratios of clay were carried out by swelling the organoclay into diol and diamine followed by addition of diisocyanate and then cured. The nanocomposites with dispersed and exfoliated structure of MMT were obtained as evidenced by X‐ray diffraction and scanning electron microscope. X‐ray diffraction showed that there is no peak corresponding to d₀₀₁ spacing in organoclay with the ratios up to 20 wt%. SEM images confirmed the dispersion of nanometer silicate layers in the polyurethane matrix. Also, it was found that the presence of organoclay leads to improvement in the mechanical properties. The tensile strength was increased with increasing the organoclay contents to 20 wt% by 221% in comparision to the PU with 0% organoclay. POLYM. COMPOS. 28:108–115, 2007. © 2007 Society of Plastics Engineers     

Effects of different compatibilizers on the rheological,thermomechanical, and morphological properties of HDPE/LLDPE blend‐based nanocomposites

The influence of two different compatibilizers and their combination (maleic anhydride grafted high density polyethylene, HDPE‐g‐MA; maleic anhydride grafted linear low density polyethylene, LLDPE‐g‐MA; and 50/50 wt % mixture of these compatibilizers) on the rheological, thermomechanical, and morphological properties of HDPE/LLDPE/organoclay blend‐based nanocomposites was evaluated. Nanocomposites were obtained by melt‐intercalation in a torque rheometer in two steps. Masterbatches (compatibilizer/nanoclay 2:1) were obtained and subsequently diluted in the HDPE/LLDPE matrix producing nanocomposites with 2.5 wt % of nanoclay. Wide angle X‐ray diffraction (WAXD), steady‐state rheological properties, and transmission electron microscopy (TEM) were used to determine the influence of different compatibilizer systems on intercalation and/or exfoliation process which occurs preferentially in the amorphous phase, and thermomechanical properties. The LLDPE‐g‐MA with a high melt index (and consequently low viscosity and crystallinity) was an effective compatibilizer for this system. Furthermore, the compatibilized nanocomposites with LLDPE‐g‐MA or mixture of HDPE‐g‐MA and LLDPE‐g‐MA exhibited better nanoclay's dispersion and distribution with stronger interactions between the matrix and the nanoclay. These results indicated that the addition of maleic anhydride grafted polyethylene facilitates both, the exfoliation and/or intercalation of the clays and its adhesion to HDPE/LLDPE blend. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1726–1735, 2013     

Physical properties of poly(trimethylene terephthalate)/organoclay nanocomposites obtained via melt compounding and in situ polymerization

Two series of poly(trimethylene terephthalate) (PTT) nanocomposites, containing an organically modified montmorillonite (MMT) clay (1,2‐aminododecanoic acid (ADA)–intercalated MMT) were prepared via melt compounding and in situ polymerization methods using dimethyl terephthalate (DMT) and 1,3‐propanediol (PDO). The effect of different methods of preparation and varying organoclay contents (1−5 wt%) on the structural, morphological, thermal, and mechanical properties were investigated. The results of wide‐angle X‐ray diffraction (WAXD) and transmission electron microscope (TEM) suggested the possible existence of intercalation morphology between ADA‐MMT and the PTT matrix obtained from melt compounding, and mostly exfoliation state from in situ polymerization depending on the amount of organoclay. From DSC studies, in melt compounding case, the addition of ADA‐MMT in PTT increases melt‐crystallization (T_cm) peak temperature by 14−15°C irrespective of the clay content. However, the melting temperature (T_m) of pristine PTT remains unchanged with increasing clay content. In the case of in situ polymerization, the T_cm and T_m peaks are shifted towards lower temperature with increasing clay content. Dynamic mechanical thermal analysis (DMTA) studies on melt compounded samples revealed a marginal lowering of glass transition temperature (T_g) irrespective of clay content, and a noticeable decrease in T_g with increasing clay content for in situ polymerized samples. The PTT/ADA‐MMT nanocomposites via melt compounding showed higher initial modulus and yield stress, and lower strain at break compared with in situ polymerization with increasing clay content. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Preparation and characterization of thermoplastic polyurethane/organoclay nanocomposites by melt intercalation technique: Effect of nanoclay on morphology,mechanical, thermal,and rheological properties

Nanocomposites based on thermoplastic polyurethane (TPU) and organically modified montmorillonite (OMMT) were prepared by melt blending. Organically modified nanoclay was added to the TPU matrix in order to study the influence of the organoclay on nanophase morphology and materials properties. The interaction between TPU matrix and nanofiller was studied by infrared spectroscopy. Morphological characterization of the nanocomposites was carried out using X‐ray diffraction, transmission electron microscopy, and scanning electron microscopy techniques. The results showed that melt mixing is an effective process for dispersing OMMT throughout the TPU matrix. Nanocomposites exhibit higher mechanical and thermal properties than pristine TPU. All these properties showed an increasing trend with the increase in OMMT content. Thermogravimetric analysis revealed that incorporation of organoclay enhances the thermal stability of nanocomposites significantly. Differential scanning calorimetry was used to measure the melting point and the glass transition temperature (T_g) of soft segments, which was found to shift toward higher temperature with the inclusion of organoclays. From dynamic mechanical thermal analysis, it is seen that addition of OMMT strongly influenced the storage and loss modulus of the TPU matrix. Dynamic viscoelastic properties of the nanocomposites were explored using rubber process analyzer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of dynamically vulcanized thermoplastic elastomer nanocomposites based on LLDPE/reclaimed rubber

Dynamically vulcanized thermoplastic elastomers nanocomposites (TPV nanocomposites) based on linear low density polyethylene (LLDPE)/reclaimed rubber/organoclay were prepared via one‐step melt blending process. Maleic anhydride grafted polyethylene (PE‐g‐MA) was used as a compatibilizing agent. The effects of reclaimed rubber content (10, 30, and 50 wt %), nanoclay content (3, 5, and 7 wt %), and PE‐g‐MA on the microstructure, thermal behavior, mechanical properties, and rheological behavior of the nanocomposites were studied. The TPV nanocomposites were characterized by X‐ray diffraction, transmission electron microscopy, scanning electron microscopy (SEM), differential scanning calorimeter, mechanical properties, and rheometry in small amplitude oscillatory shear. SEM photomicrographs of the etched samples showed that the elastomer particles were dispersed homogeneously throughout the polyethylene matrix and the size of rubber particles was reduced with introduction of the organoclay particles and compatibilizer. The effects of different nanoclay contents, different rubber contents, and compatibilizer on mechanical properties were investigated. Increasing the amount of nanoclay content and adding the compatibilizer result in an improvement of the tensile modulus of the TPV nanocomposite samples. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of the organoclay preparation on the extent of intercalation/exfoliation and barrier properties of polyethylene/PA6/montmorillonite nanocomposites

Nanocomposites of HDPE matrix and 3 wt % organoclay/PA6 discontinuous phase were prepared in a mixer chamber. These nanocomposites of organoclay, PA6, and HDPE were characterized by X‐ray diffraction, scanning electron and transmission electron microscopy (SEM and TEM). Barrier properties were determined by cyclohexane pervaporation and solubility. The results show that the degree of exfoliation and/or intercalation and the barrier properties depend on a combination of the proper chemical treatment and optimized processing in these polyethylene‐organoclays nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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     

The effect of organoclay on the mechanical properties and morphology of injection‐molded polyamide 6/polypropylene nanocomposites

Nanocomposites containing a thermoplastic blend and organophilic layered clay (organoclay) were produced by melt compounding. The blend composition was kept constant [polyamide 6 (PA6) 70 wt % + polypropylene (PP) 30 wt %], whereas the organoclay content was varied between 0 and 10 wt %. The mechanical properties of the nanocomposites were determined on injection‐molded specimens in both tensile and flexural loading. Highest strength values were observed at an organoclay content of 4 wt % for the blends. The flexural strength was superior to the tensile one, which was traced to the effect of the molding‐induced skin‐core structure. Increasing organoclay amount resulted in severe material embrittlement reflected in a drop of both strength and strain values. The morphology of the nanocomposites was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersion X‐ray analysis (EDX), and X‐ray diffraction (XRD). It was established that the organoclay is well dispersed (exfoliated) and preferentially embedded in the PA6 phase. Further, the exfoliation degree of the organoclay decreased with increasing organoclay content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 175–189, 2004     

Effects of different preparation methods on the properties of poly[ethylene‐co‐(vinyl acetate)]/(Standard Malaysian natural rubber)/organoclay nanocomposites

Poly[ethylene‐co‐(vinyl acetate)] (EVA)/(Standard Malaysian natural rubber) (SMR L)/organoclay nanocomposites were prepared by using melt intercalation and solution blending methods. In both preparation methods, the EVA: (SMR L) ratio was prefixed at 50:50, while the organoclay loading was varied from 0 to 10 phr. The effects of two different processing routes and organoclay loading on the morphology, tensile, properties thermal properties, and flammability of the nanocomposites were studied. X‐ray diffraction results and transmission electron microscopy images proved that solution blending promotes better dispersion of organoclay than melt intercalation. Thus, the nanocomposites prepared by the solution‐blending method exhibited higher values of tensile strength, stress at 100% elongation (M100), and thermal stability. The M100 value and thermal stability improved proportionally with the increase of organoclay content, owing to the demobilizing effect and the barrier properties of the organoclay. The optimum tensile strength value was achieved at a 2‐phr organoclay loading. Further increases in loading decreased the strength of the nanocomposites. Tensile fracture surfaces of the nanocomposites prepared by both methods showed different fracture behavior, as evidenced by scanning electron microscopy images. Flammability decreased when the organoclay loading increased for the nanocomposites prepared by both methods. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

Poly(ethylene‐vinyl co‐vinyl acetate)/clay nanocomposites: Mechanical,morphology, and thermal behavior

Nanocomposites of ethylene‐vinyl acetate copolymer (EVAL) with Dellite organoclay were prepared in a laboratory extruder. The extent of intercalation of the nanocomposites was studied by field emission scanning electron microscopy and X‐ray diffraction. It was established that the organoclay is well dispersed and preferentially embedded in the EVAL phase. Further, the intercalation degree of the organoclay decreased with increasing organoclay content. The mechanical properties of the nanocomposites were studied as a function of clay loading and EVAL type. The nanocomposites exhibited enhanced thermal stability as seen in thermogravimetric studies. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Preparation and characterization of polyethylene–clay nanocomposites by using chlorosilane‐modified clay

Clay was modified by trimethylchlorosilane; after modification, hydroxyl groups at the edge of layers were reacted and CEC value was drastically decreased. Polyethylene–clay composites were prepared by melt compounding. Wide angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM) showed that intercalated nanocomposites were formed using organoclay ion‐exchanged from chlorosilane‐modified clay, but conventional composites formed using organoclay directly ion‐exchanged from crude clay. Dynamic mechanical analysis (DMA) of PE and PE–clay composites was conducted; the results demonstrated that nanocomposites were more effective than conventional composites in reinforcement and addition of organoclay resulted in the increase of glass transition temperature (T_g), but crude clay had no effect on T_g of PE–clay composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 676–680, 2004     

Nanocomposites of poly(trimethylene terephthalate) with organoclay

Two different kinds of clay were organomodified with cetylpyridinium chloride (CPC) as an intercalation agent. Poly(trimethylene terephthalate) (PTT)/organoclay nanocomposites were prepared by the solution intercalation method. Wide‐angle X‐ray diffraction (WAXD) indicated that the layers of clay were intercalated by CPC and the interlayer spacing was a function of the cationic exchange capacity (CEC) of the clay: the higher the CEC, the larger the interlayer spacing is. The WAXD studies showed that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay. From the results of differential scanning calorimetry analysis it was found that clay behaves as a nucleating agent and enhances the crystallization rate of PTT. The maximum enhancement of the crystallization rate for the nanocomposites was observed in nanocomposites containing about 5 wt % organoclay with a range of 1–15 wt %. The thermal stability of the nanocomposites was enhanced by the addition of 1–10 wt % organoclay as found from thermogravimetric analysis. The thermal stability of the PTT/organoclay nanocomposites was related to the organoclay content and the dispersion in the PTT matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3315–3322, 2003