Polylactide/montmorillonite nanocomposites: Structure, dielectric, viscoelastic and thermal properties

Polylactide-based systems composed of an organoclay (Cloisite^® 30B) and/or a compatibilizer (Exxelor VA1803) prepared by melt blending were investigated. Two types of not compatibilized nanocomposites containing 3 wt% or 10 wt% of the organoclay were studied to reveal the effect of the filler concentration on the nanostructure and physical properties of such systems. The 3 wt%-nanocomposite was also additionally compatibilized in order to improve the nanoclay dispersion. Neat polylactide and polylactide with the compatibilizer processed in similar conditions were used as reference samples. The X-ray investigations showed the presence of exfoliated nanostructure in 3 wt%-nanocomposite. Compatibilization of such system noticeably enhanced the degree of exfoliation of the organoclay. Viscoelastic spectra (DMTA) showed an increase of the storage and loss moduli with the increase of the organoclay content and dispersion. Dielectric properties of the nanocomposites show a weak influence of the nanoclay on segmental (α_S) and local (β)-relaxations in PLA, except for the highest nanoclay content. Above T_g a strong increase of dc conductivity related to ionic species in the clay is observed. It gives rise also to the Maxwell-Wagner-Sillars interfacial polarization and both real and imaginary parts of ε strongly increase. In the temperature dependence of low frequency dielectric constant and mechanical moduli (at 1 Hz) an additional maximum around 80-90 °C is observed due to cold crystallization of PLA.     

Nanocomposites by melt intercalation based on polycaprolactone and organoclay

Nanocomposites based on biodegradable polycaprolactone (PCL) and organically modified layered silicates (organoclay) were prepared by melt mixing. Their structures and properties were characterized by wide‐angle X‐ray diffraction, thermal analysis, and rheological measurements. The exfoliation of the organoclay was achieved via a melt mixing process in an internal mixer and showed a dependence on the type of organic modifier, the organoclay contents, and the processing temperature. The addition of the organoclay to PCL increased the crystallization temperature of PCL, but a high content of the organoclay could show an inverse effect. The PCL/organoclay nanocomposites showed a significant enhancement in their mechanical properties and thermal stability due to the exfoliation of the organoclay. The nanocomposites showed a much higher complex viscosity than the neat PCL and significant shear‐thinning behavior in the low frequency range. The shear storage modulus and loss modulus of the nanocomposites also exhibited less frequency dependence than the pure PCL in the low frequency range, and this was caused by the strong interactions between the organoclay layers and PCL molecules and by the good dispersion of exfoliated organoclay platelets in the PCL. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 670–678, 2003     

Barrier and Mechanical Properties of Poly(caprolactone)/organoclay Nanocomposites

In this study, biodegradable poly(caprolactone) (PCL) hybrids with two types of organoclays: Cloisite 30B (30B) and Cloisite 93A (93A) have been prepared by melt mixing and their barrier performance to air permeation and mechanical properties were investigated. The hybrids of PCL/30B were found to be nanocomposites resulted from the strong interaction between organic modifier of 30B and PCL and those of PCL/93A were microcomposites. The barrier performance of PCL/30B nanocomposite film to air permeation was much more improved than pure PCL and PCL/93A microcomposites at low organoclay concentration. With the increase of organoclay content the permeability coefficient was also increased that could attributed to the extra tortuous pathway for gas permeation caused by organoclay exfoliation. The barrier behaviour of PCL/30B nanocomposites could be approximately described by a theoretical model developed for composites. The mechanical properties measurements showed that the reinforcement of organoclay 30B in nanocomposites is more significant than 93A in microcomposites. Both tensile modulus and tensile strength were increased in PCL/30B nanocomposites even at at low amount of organoclay without much loss of strain at break as compared to pure PCL. The significant improvements in both barrier and mechanical properties in PCL nanocomposites could be attributed to the fine dispersion state of organoclay 30B platelets in PCL matrix and the strong interaction between organic modifier of 30B and matrix molecules.     

Polylactide/exfoliated graphite nanocomposites with enhanced thermal stability,mechanical modulus,and electrical conductivity

We have prepared a series of polylactide/exfoliated graphite (PLA/EG) nanocomposites by melt‐compounding and investigated their morphology, structures, thermal stability, mechanical, and electrical properties. For PLA/EG nanocomposites, EG was prepared by the acid treatment and following rapid thermal expansion of micron‐sized crystalline natural graphite (NG), and it was characterized to be composed of disordered graphite nanoplatelets. It was revealed that graphite nanoplatelets of PLA/EG nanocomposites were dispersed homogeneously in the PLA matrix without forming the crystalline aggregates, unlike PLA/NG composites. Thermal degradation temperatures of PLA/EG nanocomposites increased substantially with the increment of EG content up to ～3 wt %, whereas those of PLA/NG composites remained constant regardless of the NG content. For instance, thermal degradation temperature of PLA/EG nanocomposite with only 0.5 wt % EG was improved by ～10 K over PLA homopolymer. Young's moduli of PLA/EG nanocomposites increased noticeably with the increment of EG content up to ～3 wt %, compared with PLA/NG composites. The percolation threshold for electrical conduction of PLA/EG nanocomposites was found to be at 3–5 wt % EG, which is far lower graphite content than that (10–15 wt % NG) of PLA/NG composites. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 850–858, 2010     

Shear‐induced clay dispersion in HDPE/PEgMA/organoclay composites as studied via real‐time rheological method

In current study, a real‐time rheological method was used to investigate the intercalation and exfoliation process of clay in high‐density polyethylene/organoclay (HDPE/OMMT) nanocomposites using maleic anhydride grafted polyethylene (PEgMA) as compatibilizer. To do this, a steady shear was applied to the original nonintercalated or slightly intercalated composites prepared via simple mixing. The moduli of the composites were recorded as a function of time. The effect of matrix molecular weight and the content of compatibilizer on the modulus were studied. The role of the compatibilizer is to enhance the interaction between OMMT and polymer matrix, which facilitates the dispersion, intercalation, and exfoliation of OMMT. The matrix molecular weight determines the melt viscosity and affects the shear stress applied to OMMT platelets. Based on the experimental results, different exfoliation processes of OMMT in composites with different matrix molecular weight were demonstrated. The slippage of OMMT layers is suggested in low‐molecular weight matrix, whereas a gradual intercalation process under shear is suggested in high‐molecular weight matrix. Current study demonstrates that real‐time rheological measurement is an effective way to investigate the dispersion, intercalation, and exfoliation of OMMT as well as the structural change of the matrix. Moreover, it also provides a deep understanding for the role of polymer matrix and compatibilizer in the clay intercalation process. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 302–312, 2010     

Poly(lactic acid) nanocomposites with various organoclays. I. Thermomechanical properties,morphology, and gas permeability

The thermomechanical properties, morphology, and gas permeability of hybrids prepared with three types of organoclays were compared in detail. Hexadecylamine–montmorillonite (C₁₆–MMT), dodecyltrimethyl ammonium bromide–montmorillonite (DTA‐MMT), and Cloisite 25A were used as organoclays in the preparation of nanocomposites. From morphological studies using transmission electron microscopy, most clay layers were found to be dispersed homogeneously in the matrix polymer, although some clusters or agglomerated particles were also detected. The initial degradation temperature (at a 2% weight loss) of the poly(lactic acid) (PLA) hybrid films with C₁₆–MMT and Cloisite 25A decreased linearly with an increasing amount of organoclay. For hybrid films, the tensile properties initially increased but then decreased with the introduction of more of the inorganic phase. The O₂ permeability values for all the hybrids for clay loadings up to 10 wt % were less than half the corresponding values for pure PLA, regardless of the organoclay. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 94–103, 2003     

The influence of reactive organoclay on a biorenewable castor oil‐based polyurethane prepolymers toughened polylactide nanocomposites

Polylactide (PLA) is the most extensively reviewed and utilized biodegradable and renewable thermoplastic polyester, with potential to replace conventional petroleum‐based polymeric materials. To improve the toughness of PLA, castor oil‐based polyurethane prepolymer (COPUP) toughened PLA nanocomposites were prepared via the melt mixing process and investigated for its mechanical, thermal and morphological properties. X‐ray diffraction and transmission electron microscopy studies revealed the formation of polymer blend nanocomposites. Mechanical tests revealed optimum performance characteristics at PLA/COPUP ratio of 70:30. Further, loading of the organoclay showed higher tensile strength and modulus of the blend nanocomposites as compared to optimized blend. The morphological results indicated that the surface roughness increases as a function of the organoclay incorporation. Thermogravimetric measurements reveal that the thermal stability of the blend increases with the incorporation of organoclay. The improved mechanical properties along with its biodegradability might lead to new industrial and biomedical applications. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of organoclay on the curing reactions in bismaleimide/diallyl bisphenol a resin

4,4′‐Bismaleimidodiphenyl methane (BMPM)/2,2′‐diallyl bisphenol A (DBA)/organoclay nanocomposites were synthesized. The effects of organoclays on the curing reactions in the BMPM/DBA system at low temperatures (ene reaction) and high temperatures (Diels–Alder reaction, homopolymerization of BMPM, and alternative copolymerization) were investigated with differential scanning calorimetry and Fourier transform infrared techniques. The results showed that these reactions were affected to different extents in the presence of organoclays. The ene reaction was accelerated to different degrees depending on the acidity of the modifier and the accessibility of the organoclays used. The exfoliation degree of organoclays in the prepolymers showed great effects on the curing behavior of BMPM/DBA. When an organoclay was less intercalated, the curing behavior of the system was different from that of neat BMPM/DBA. On the other hand, when the organoclay was better exfoliated in prepolymers, the curing behavior of the system was similar to that of the neat BMPM/DBA system. However, even in this case, the reactions at high temperatures occurred in different ways in the presence of an organoclay. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 994–1006, 2005     

An observation of accelerated exfoliation in iPP/organoclay nanocomposite as induced by repeated shear during melt solidification

A well‐exfoliated morphology is usually observed for polar polymer/clay nanocomposites via dynamic melt processing techniques, whereas only an intercalated or a partially intercalated/partially exfoliated morphology is often obtained for nonpolar polymer/clay nanocomposites, even though some polar compatibilzer is used. In this study, an accelerated exfoliation effect was observed for the first time in iPP/organoclay nanocomposites prepared through so‐called dynamic packing injection molding, in which the specimen is forced to move repeatedly in a chamber by two pistons that move reversibly with the same frequency as the solidification progressively occurs from the mold wall to the molding core part. The disordered level and exfoliated degree of clay was found to dramatically increase from the skin to the core of the prepared samples and eventually the WAXD reflections of interlayer d‐spacing diminished in the core. The changed degree of exfoliation was also proved directly by TEM observation. The prolongation of processing time, the gradual growth of solidification front, the increased melts viscosity, and the shear amplification effect were considered to explain the higher degree of exfoliation in the center zone of mold chamber. Our result suggests that a critical shear force may be needed to break down clay into exfoliated structure. This can be also well used to explain at least partially the intercalated morphology, which is commonly observed for nonpolar polymer/clay nanocomposites via conventional processing. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2005–2012, 2005     

Polyolefin-based nanocomposite: The effect of organoclay modifier

Polypropylene (PP) nanocomposites were prepared using montmorillonite with different organic modifiers, and the effect of processing aid (EMCA and PPG) on the dispersion of the nanofillers in the PP matrix was evaluated by WAXD, TEM, DSC, TGA, DMA, and mechanical tests. The present study helps to clarify the effects of the organic modifiers of clays on the intercalation and exfoliation processes. Nanocomposites of intercalated and partially exfoliated morphology were obtained, mainly when a low amount (1:1) of PP-g-MA/MMT was used. The results of the tests on mechanical properties showed that the clays with larger d₀₀₁ (C-15A and Nanofil 5) using PPG presented a more considerable gain in impact strength. The nanocomposites using clays with smaller d₀₀₁(C-20A) presented larger modulus when compared with those of pristine PP. The heat deflection temperature, crystallization temperature, and thermal stability of the nanocomposites were improved compared to neat PP. The DMA results showed that the organoclay improved the modulus of PP, but decreased the T_g. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2519–2531, 2008     

Extruder‐made TPO nanocomposites. I. Effect of maleated polypropylene and organoclay ratio on the morphology and mechanical properties

PP/PP‐g‐MA/MMT/EOR blend nanocomposites were prepared in a twin‐screw extruder at fixed 30 wt % elastomer and 0 to 7 wt % MMT content. Elastomer particle size and shape in the presence of MMT were evaluated at various PP‐g‐MA/organoclay masterbatch ratios of 0, 0.5, 1.0, and 1.5. The organoclay dispersion facilitated by maleated polypropylene serves to reduce the size of the elastomer dispersed phase particles and facilitates toughening of these blend nanocomposites. The rheological data analysis using modified Carreau‐Yasuda model showed maximum yield stress in extruder‐made nanocomposites compared with nanocomposites of reactor‐made TPO. Increasing either MMT content or the PP‐g‐MA/organoclay ratio can drive the elastomer particle size below the critical particle size below which toughness is dramatically increased. The ductile‐brittle transition shift toward lower MMT content as the PP‐g‐MA/organoclay ratio is increased. The D‐B transition temperature also decreased with increased MMT content and masterbatch ratio. Elastomer particle sizes below ～1.0 μm did not lead to further decrease in the D‐B transition temperature. The tensile modulus, yield strength, and elongation at yield improved with increasing MMT content and masterbatch ratio while elongation at break was reduced. The modified Mori‐Tanaka model showed better fit to experimental modulus when the effect of MMT and elastomer are considered individually. Overall, extruder‐made nanocomposites showed balanced properties of PP/PP‐g‐MA/MMT/EOR blend nanocomposites compared with nanocomposites of reactor‐made TPO. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Review of melt‐processed nanocomposites based on EVOH/organoclay

EVOH nanocomposites containing organically treated clays are unique systems in which the clay is strongly attracted to EVOH, thus affecting the morphology and the resultant thermal and mechanical properties. A strong effect of the processing conditions on morphology, thermal, and mechanical properties was observed. In highly interacting systems, under dynamic mixing conditions, in addition to a fracturing process of the clay particles, an onion‐like delamination process is suggested. EVA‐g‐MA and LLDPE‐g‐MA, having polar groups, were studied as compatibilizers to further induce clay intercalation and exfoliation. The compatibilizers affected both the thermal and mechanical properties of the composites at different levels. Thermal analysis showed that with increasing compatibilizer content lower crystallinity levels result, until at a certain content no crystallization has taken place. A Ny‐6 (nylon‐6)/EVOH blend is an interesting host matrix for incorporation of low organoclay contents. The Ny‐6/EVOH blend is a unique system that tends to hydrogen bond and also to in situ chemically react during melt mixing. The addition of clay seems to interrupt the chemical reaction between the two host polymers at certain compositions, leading to lower melt blending torque levels when clay is present. A competition between Ny‐6 and EVOH regarding the intercalation process takes place. However, Ny‐6 seems to lead to exfoliated structures, whereas EVOH forms intercalated structures, as revealed from combined XRD and TEM experiments, owing to thermodynamic considerations and preferential localization of the clay in Ny‐6. Of special interest is the increased storage modulus seen by the presence of only 1 wt % clay, which was achieved by extrusion under high shear forces, leading to a completely exfoliated structure. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1931–1943, 2005     

4,4'-二氨基二苯醚二苯酮固化环氧树脂/粘土纳米复合材料的研究

采用离子交换法, 用十六烷基三甲基溴化铵处理钙基蒙脱土(MMT), 使蒙脱土的层间距由1.49 nm扩大到2.21 nm, 制备了环氧树脂/ BADK/MMT纳米复合材料, 并用XRD等手段研究了有机蒙脱土在环氧树脂中的插层及剥离行为. 研究结果表明, 蒙脱土含量及环氧树脂与有机土的混合温度和时间均对固化后复合材料的剥离产生影响, 只有在特定条件下才能得到剥离型纳米复合材料.     

Melt rheology of polylactide/montmorillonite nanocomposites

In this article, the linear and nonlinear shear rheological behaviors of polylactide (PLA)/clay (organophilic‐montmorillonite) nanocomposites (PLACNs) were investigated by an Advanced Rheology Expanded System rheometer. The nanocomposites were prepared by master batch method using a twin‐screw extruder with poly(ε‐caprolactone) (PCL) as a compatibilizer. The presence of org‐MMT leads to obvious pseudo‐solid‐like behaviors of nanocomposite melts. The behaviors caused by the formation of a “percolating network” derived from the reciprocity among the strong related sheet particles. Therefore, the storage moduli, loss moduli, and dynamic viscosities of PLACNs show a monotonic increase with MMT content. Nonterminal behaviors exists in PLACNs nanocomposites. Besides the PLACNs melts show a greater shear thinning tendency than pure PLA melt because of the preferential orientation of the MMT layers. Therefore, PLACNs have higher moduli but better processibility compared with pure PLA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3189–3196, 2007     

Plasticized polylactide/clay nanocomposites. I. The role of filler content and its surface organo‐modification on the physico‐chemical properties

Polylactide (PLA)‐layered silicate nanocomposites plasticized with 20 wt % of poly(ethylene glycol) 1000 were prepared by melt blending. Three kinds of organo‐modified montmorillonites—Cloisite® 20A, Cloisite® 25A, and Cloisite® 30B—were used as fillers at a concentration level varying from 1–10 wt %. Neat PLA and plasticized PLA with the same thermomechanical history were considered for comparison. Nanocomposites based on amorphous PLA were obtained via melt‐quenching. The influence of both plasticization and nanoparticle filling on the physicochemical properties of the nanocomposites were investigated. Characterization of the systems was achieved by size exclusion chromatography (SEC), thermogravimetric analysis (TGA), thermally modulated differential scanning calorimetry (TMDSC), X‐ray diffraction (XRD), and dynamic mechanical analysis (DMTA). SEC revealed a decrease of the molecular weight of the PLA matrix with the filler content. Thermal behavior on heating showed one cold crystallization process in the reference neat PLA sample, while two cold crystallization processes in plasticized PLA and plasticized nanocomposites. The thermal windows of these processes tend to increase with the filler content. The crystalline form of PLA developed upon heating was affected neither by the plasticization nor by the type and content of Cloisite used. It was found that the series of organo‐modified montmorillonites with decreasing affinity to PLA is Cloisite® 30B, Cloisite® 20A, and Cloisite® 25A, respectively. The dynamic mechanical properties were sensitive to the sample composition. Generally, the storage modulus increased with the filler content. Glassy PEG, well dispersed within unfilled PLA matrix, exhibited also a reinforcing effect, since the storage modulus of this sample was higher than for unplasticized reference at temperature region below the glass transition of PEG. Moreover, loss modulus of all plasticized samples revealed an additional maximum ascribed to the glass transition of PEG–rich dispersed phase, indicating partial miscibility of organic components of the systems investigated. The magnitude of this mechanical loss was correlated with the filler content, and to some extent, also with the nanofiller ability to be intercalated by polymer components. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 299–311, 2006     

混合条件对环氧有机土纳米复合材料插层剥离行为及性能的影响

采用X 射线衍射仪、透射电镜 (TEM )研究了混合条件 ,即混合温度和时间 ,对环氧 /16 烷基胺有机蒙脱土体系在固化前的混合物以及加入固化剂、促进剂固化后有机土的插层与剥离行为的影响 .同时采用拉伸试验机、冲击试验机和热机械分析仪测定了插层与剥离型纳米复合材料的物理力学性能 .从X 射线衍射看出 ,有机土很容易在混合过程被环氧所插层 .混合物经固化后可以形成插层型或剥离型纳米复合材料 .存在一个混合温度 时间 插层剥离转变的 3 T图 .只有在一定的混合条件的区域内才能形成剥离型纳米复合材料 .剥离型比插层型纳米复合材料具有较高的力学性能     

Crystallization behavior and thermal stability of poly(trimethylene terephthalate)/clay nanocomposites

Poly(trimethylene terephthalate) (PTT)/montmorillonite (MMT) nanocomposites were prepared by the solution intercalation method. Two different kinds of clay were organomodified with an intercalation agent of cetyltrimetylammonium chloride (CMC). X‐ray diffraction (XRD) indicated that the layers of MMT were intercalated by CMC, and interlayer spacing was a function of the cationic exchange capacity of clay. The XRD studies demonstrated that the interlayer spacing of organoclay in the nanocomposites depends on the amount of organoclay. From the results of differential scanning calorimetric 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 1 wt % organoclay with a range of 1–15 wt %. From thermogravimetric analysis, we found that the thermal stability of the nanocomposites was enhanced by the addition of 1–10 wt % organoclay. According to transmission electron microscopy, the organoclay particle was highly dispersed in the PTT matrix without a large agglomeration of particles for a low organoclay content (5 wt %). However, an agglomerated structure did form in the PTT matrix at a 15 wt % organoclay content. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2902–2910, 2003     

Effect of clay modification on the structure and mechanical properties of polyamide-6 nanocomposites

Polyamide-6 nanocomposites were prepared from a new phosphonium organoclay obtained at pilot scale in supercritical carbon dioxide (scCO₂) and a commercially available ammonium modified-silicate. The composites were homogenised by twin-screw extrusion, then specimens for testing were prepared by injection moulding. The clay content of the composites was varied from 0 to 7 vol.% in 7 steps. The clays were characterised in detail; they differed in their surface coverage and gallery structure, while their particle size was similar and their surface energy differed only slightly. X-ray diffraction, electronic microscopy and rheology were used for the characterisation of composite structure. Different gallery structure of the clays led to dissimilar extent of exfoliation. The phosphonium organoclay exfoliated better in PA than the silicate treated with the ammonium salt in spite of its smaller surface coverage. The nanocomposites showed the usual complex structure: besides individual platelets and intercalated stacks, large particles were also present and the development of a silicate network could be shown at large clay contents. Quantitative determination of the extent of reinforcement revealed two determining factors: contact surface and strength of interaction. The first increases with exfoliation, but the latter decreases as an effect of organophilisation. The extent of exfoliation was also estimated quantitatively, and the calculation confirmed the results of qualitative evaluation showing larger extent of exfoliation for the scCO₂-prepared phosphonium clay.     

Mechanical properties of clay‐reinforced polyamide

Intercalated and exfoliated nanocomposites were prepared by extrusion and injection of polyamide‐6 and highly swollen or slightly swollen montmorillonite, respectively. The microstructure of the nanocomposites has been studied previously. In this article, we investigated the influence of the preferential orientation of the montmorillonite sheets on the mechanical properties of the nanocomposites. Dynamic mechanical analysis and tensile tests showed that the elastic modulus depends mainly on the filler loading. A parallel coupling could well account for the behavior of the nanocomposites. The calculated elastic and storage moduli of montmorillonite were set to 140 and 40 GPa, respectively. Compression tests were performed to study the anisotropy of the mechanical properties. The elastic modulus and flow strain were sensitive to the filler orientation. A Tandon–Weng approach was applied to consider the geometry of the filler. In all low‐deformation tests, no significant difference between intercalated and exfoliated systems was observed. Finally, the influence of the dispersion and exfoliation state of the filler on the ultimate properties of the nanocomposites (tensile tests) is discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 40: 272–283, 2002     

Synthesis and characterization of a series of thermotropic liquid crystalline copolyester nanocomposites

A series of aromatic thermotropic liquid crystalline copolyester (TLCP) nanocomposites were prepared by the in situ intercalation polymerization of p‐acetoxybenzoic acid (ABA), terephthalic acid (TPA), and diacetoxynaphthalene (DAN) isomers in the presence of the organoclay. The DAN isomers used in this study were 2,3‐ and 2,7‐naphthylene. We examined the variation of the liquid crystallinity, morphology, and thermal properties of the nanocomposites with organoclay content in the range 0–10 wt %. All the polymer nanocomposites were fabricated with a molar ratio of ABA:TPA:DAN = 2:1:1; they were shown to consist of a nematic liquid crystalline phase for low organoclay contents (≤5 wt %), whereas the hybrids with a higher concentration of organoclay (≥10 wt %) were found not to be mesomorphic. By using transmission electron microscopy, the clay layers in the 2,3‐DAN copolyester hybrids were found to be better dispersed in the matrix polymer than those in the 2,7‐DAN copolyester hybrids. The introduction of an organoclay into the matrix polymer was found to improve the thermal properties of the 2,3‐DAN copolyester hybrids. However, the thermal properties of the 2,7‐DAN copolyester hybrids were found to be worse than those of the pure matrix polymer for all organoclay compositions tested. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 387–397, 2006