Synthesis and characterization of poly(urethane‐benzoxazine)/clay hybrid nanocomposites

Poly(urethane‐benzoxazine)/clay hybrid nanocomposites (PU/Pa–OMMTs) were prepared from an in situ copolymerization of a polyurethane (PU) prepolymer and a monofunctional benzoxazine monomer, 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (Pa), in the presence of an organophilic montmorillonite (OMMT), by solvent method using DMAc. OMMT was made from cation‐exchange of Na‐montmorillonite (MMT) with dodecyl ammonium chloride. The formation of the exfoliated nanocomposite structures of PU/Pa‐OMMT was confirmed by XRD from the disappearance of the peak due to the basal diffraction of the layer‐structured clay found in both MMT and OMMT. DSC showed that, in the presence of OMMT, the curing temperature of PU/Pa lowered by ca. 60°C for the onset and ca. 20°C for the maximum. After curing at 190°C for 1 h, the exothermic peak on DSC disappeared. All the obtained films of PU/Pa–OMMT were deep yellow and transparent. As the content of OMMT increased, both the tensile modulus and strength of PU/Pa–OMMT films increased, while the elongation decreased. The characteristics of the PU/Pa–OMMT films changed from plastics to elastomers depending on OMMT content and PU/Pa ratio. PU/Pa–OMMT films also exhibited excellent resistance to the solvents such as tetrahydrofuran, N,N‐dimethylformamide and N‐methyl‐2‐pyrrolidinone. The thermal stability of PU/Pa were enhanced remarkably even with small amount of OMMT. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4075–4083, 2003     

Influence of the type of quaternary ammonium salt used in the organic treatment of montmorillonite on the properties of poly(styrene‐co‐butyl acrylate)/layered silicate nanocomposites prepared by in situ miniemulsion polymerization

Hybrid latices of poly(styrene‐co‐butyl acrylate) were synthesized via in situ miniemulsion polymerization in the presence of 3 and 6 wt % organically modified montmorillonite (OMMT). Three different ammonium salts: cetyl trimethyl ammonium chloride (CTAC), alkyl dimethyl benzyl ammonium chloride (Dodigen), and distearyl dimethyl ammonium chloride (Praepagen), were investigated as organic modifiers. Increased affinity for organic liquids was observed after organic modification of the MMT. Stable hybrid latices were obtained even though miniemulsion stability was disturbed to some extent by the presence of the OMMTs during the synthesis. Highly intercalated and exfoliated polymer‐MMT nanocomposites films were produced with good MMT dispersion throughout the polymeric matrix. Materials containing MMT modified with the 16 carbons alkyl chain salt (CTAC) resulted in the largest increments of storage modulus, indicating that single chain quaternary salts provide higher increments on mechanical properties. Films presenting exfoliated structure resulted in the largest increments in the onset temperature of decomposition. For the range of OMMT loading studied, the nanocomposite structure influenced more significantly the thermal stability properties of the hybrid material than did the OMMT loading. The film containing 3 wt % MMT modified with the two 18 carbons alkyl chains salt (Praepagen) provided the highest increment of onset temperature of decomposition. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Unsaturated polyester/montmorillonite nanocomposites with improved mechanical and thermal properties fabricated by in situ polymerization

Although organically modified montmorillonite (OMMT) has been incorporated into unsaturated polyester (UP) resin to enhance properties, the aggregation often leads to defects which directly affect the properties of nanocomposites. In this work, OMMT slurry modified by a new allyl surfactant with carbon–carbon double bond, hexadecyl allyl dimethyl ammonium chloride (C₁₆‐DMAAC), was employed to prepare nanocomposites by in situ polymerization. The results illustrated that the existence of OMMT slurry helped monomers enter the OMMT galleries, leading to well‐dispersed OMMT in the UP matrix. The mechanical properties and thermal properties of OMMT nanocomposites were improved. With OMMT loading of 5 wt %, the tensile strength and flexural strength can be improved by 22% and 38%, respectively. Meanwhile, the onset thermal decomposition temperature (T_–10) value was ameliorated from 310.6 °C to 330.6 °C. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45251.     

Preparation of an organomontmorillonite master batch and its application to high‐temperature‐vulcanized silicone‐rubber systems

N,N‐Di(2‐hydroxyethyl)‐N‐dodecyl‐N‐methyl ammonium chloride was used as an intercalation agent to treat Na⁺‐montmorillonite and form a novel type of organic montmorillonite (OMMT). An OMMT master batch (OMMT‐MB) was prepared by solution intercalation and was used in the preparation of high‐temperature‐vulcanized silicone rubber (HTV‐SR)/OMMT‐MB nanocomposites. The properties, such as the tensile and thermal stability, were researched and compared with those of composites directly incorporated with OMMT or aerosilica. A combination of Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, and transmission electron microscopy studies showed that HTV‐SR/OMMT‐MB composites were on the nanometer scale, and their structure was somewhat hindered by the presence of OMMT. The results showed that the tensile properties of HTV‐SR/OMMT‐MB and HTV‐SR/OMMT systems were better than those of pure HTV‐SR. Compared with those of HTV‐SR/OMMT‐20%, the tensile strength and elongation at break of HTV‐SR/OMMT‐MB‐20% were improved about 1.5 and 0.9 times, respectively. This was probably due to the nanoeffect of the exfoliated silicate layers. Moreover, the tensile strength of HTV‐SR/OMMT‐MB‐20% was nearly equal to that of HTV‐SR/aerosilica‐20%, and the elongation at break even showed much improvement. Additionally, the thermal degradation center temperature of the HTV‐SR/OMMT‐MB‐20% nanocomposite was increased by 30°C compared with that of the HTV‐SR/OMMT‐20% composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Enhanced mechanical and thermal properties of polyimide/organically modified montmorillonite hybrid film based on stable poly(amic acid) ammonium salt

In this study, polyimide/organically modified montmorillonite (PI/OMMT) hybrid film was prepared by in situ polymerization from the stable poly(amic acid) ammonium salt/OMMT (PAAS/OMMT) precursor hybrid. PAAS was obtained by incorporating calculated triethylamine into terpolymer poly(amic acid) (PAA), which was synthesized by pyromellitic dianhydride (PMDA), 4,4′‐oxydianiline and p‐phenylenediamine in dimethylacetamide (DMAc). OMMT as a type of layered clays was prepared through surface treatment of montmorillonite (MMT) with 1‐hexadecylamine. Mechanical property measurements of PI/OMMT hybrid film indicated that the addition of 5 wt% of OMMT increased the Young's modulus of PI film up to 11.24 GPa, which is 58% higher than the pristine PI film from PAAS. Besides, the tensile strength increased to 168.36 MPa, which was higher than that of PI film derived from PAA (164.3 MPa) and PI film derived from PAAS (145.2 MPa). Moreover, the thermal stabilities of PI/OMMT hybrid film with appropriate OMMT content were also better than those of original PI films. POLYM. COMPOS., 34:2076–2081, 2013. © 2013 Society of Plastics Engineers     

Influence of the clay modification and compatibilizer on the structure and mechanical properties of ethylene–propylene–diene rubber/montmorillonite composites

Ethylene–propylene–diene rubber (EPDM)/montmorillonite (MMT) composites were prepared through a melt process, and three kinds of surfactants with different ammonium cations were used to modify MMT and affect the morphology of the composites. The morphology of the composites depended on the alkyl ammonium salt length, that is, the hydrophobicity of the organic surfactants. Organophilic montmorillonite (OMMT), modified by octadecyltrimethyl ammonium salt and distearyldimethyl ammonium salt, was intercalated and partially exfoliated in the EPDM matrix, whereas OMMT modified by hexadecyltrimethyl ammonium chloride exhibited a morphology in which OMMT existed as a common filler. Ethylene–propylene–diene rubber grafted with maleic anhydride (MAH‐g‐EPDM) was used as a compatibilizer and greatly affected the dispersion of OMMT. When OMMTs were modified by octadecyltrimethyl ammonium chloride and distearydimethyl ammonium chloride, the EPDM/OMMT/MAH‐g‐EPDM composites (100/15/5) had an exfoliated structure, and they showed good mechanical properties and high dynamic moduli. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 638–646, 2004     

Synthesis of hyperbranched organo‐montmorillonite and its application into high‐temperature vulcanizated silicone rubber systems

N,N‐Di(2‐hydroxyethyl)‐N‐dodecyl‐N‐methyl ammonium chloride was used as intercalation agent to treat Na⁺‐montmorillonite and form a type of organic montmorillonite (OMMT). Hyperbranched OMMT (HOMMT) was prepared by condensation reaction between OMMT and the monomer we synthesized. It was then used in the preparation of high‐temperature vulcanizated silicone rubber (HTV‐SR)/HOMMT nanocomposite. Different types of HTV‐SR/HOMMT nanocomposites were prepared with different amounts of HOMMT and compared with the composites directly incorporated with OMMT. Tensile properties such as tensile strength, elongation at break, permanent distortion, and shore A hardness were researched and compared. A combination of Fourier transform infrared spectroscopy, wide angle X‐ray diffraction, and transmission electron microscopy studies showed that HTV‐SR/HOMMT composites were on the nanometer scale, and the structure of HTV‐SR was not interfered by the presence of HOMMT. Results showed that the tensile properties of HTV‐SR/HOMMT systems were better than that of the HTV‐SR/HOMMT and HTV‐SR. This was probably due to the surface effect of the exfoliated silicate layers and anchor effect of HOMMT in the SR matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of polypropylene–montmorillonite nanocomposites generated by in situ metallocene catalyst polymerization

An ion‐exchange method was applied to replace sodium cations inside the interlamellar space of montmorillonite with positively charged stearyl trimethyl ammonium chloride. The d₀₀₁‐spacing of montmorillonite is larger in toluene than in other solvents. The overexchanged stearyl methyl ammonium chloride in the montmorillonite layers can be completely washed out by ethanol. Polypropylene–montmorillonite nanocomposites were prepared by using the supported rac‐Et(Ind)₂ZrCl₂ catalyst on the montmorillonite. The nanocomposites that were polymerized by the supported catalyst were characterized by infrared spectroscopy, nuclear magnetic resonance, X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. Transmission electron microcopy shows that each silicate sheet of montmorillonite is randomly dispersed into the polypropylene matrix following polymerization by using a supported catalyst. The polypropylene nanocomposites had higher crystallinity, hardness, and thermal properties than pure polypropylene. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1228–1236, 2005     

The effect of clay modification on the mechanical properties of poly(methyl methacrylate)/organomodified montmorillonite nanocomposites prepared by in situ suspension polymerization

Poly(methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization. MMT was previously organically modified by different modification agents [dioctadecyl dimethyl ammonium chloride (DODAC) and methacrylatoethyltrimethyl ammonium chloride (MTC)] and different modification method (cation‐exchange reaction and grafting reaction), ultimately giving rise to five kinds of organomodified MMT (OMMT). The structure of the OMMT was studied by Wide angle X‐ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR). Meanwhile, the structure of the PMMA/MMT nanocomposites microspheres was also investigated by WAXD. The molecular weight of the polymers extracted from PMMA/MMT nanocomposites was measured by gel permeation chromatograph (GPC). Finally, the mechanical properties of these PMMA/MMT nanocomposites were studied in detail. It was found that large interlayer spacing (d₀₀₁) of OMMT could not entirely ensure an exfoliated structure of resultant PMMA/MMT nanocomposites, while OMMT with relative small d₀₀₁ could still yield exfoliated structure as long as the compatibility between OMMT and polymer matrix was favorable. In addition, the results of mechanical investigation indicated that the compatibility between OMMT and PMMA matrix turned out to be the dominant factor deciding the final mechanical properties of PMMA/MMT nanocomposites. POLYM. COMPOS., 37:1705–1714, 2016. © 2014 Society of Plastics Engineers     

Synthesis and properties of organosoluble polyimide/clay hybrids

A soluble polyimide prepared from 7,7′‐bis(4‐aminophenoxy)‐4,4,4′,4′‐tetramethyl‐2,2′‐spirobichroman and 4,4′‐hexafluoroisopropylidenediphthalic anhydride was mixed with organo‐modified montmorillonite or synthetic mica in N,N‐dimethylacetamide. The content of the clay minerals was 1, 2, and 4 wt %, respectively. Transparent, flexible, and tough films could be cast from the hybrid solutions. The hybrid films were characterized with wide‐angle X‐ray scattering (WAXS), transmission electron microscopy, thermomechanical analysis, thermogravimetric analysis, and differential scanning calorimetry. The WAXS results revealed that the montmorillonite was dispersed more homogeneously than the synthetic mica in the polyimide matrix. In both polyimide/clay hybrids the addition of clay caused thermal expansion coefficients to decrease, and the thermal stability was slightly enhanced. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2067–2072, 2001     

Poly(methyl methacrylate)/montmorillonite nanocomposites prepared with a novel reactive phosphorus–nitrogen‐containing monomer of N‐(2‐(5,5‐dimethyl‐1,3,2‐dioxaphosphinyl‐2‐ylamino)ethyl)‐ acrylamide and its thermal and flame retardant properties

A novel reactive phosphorus–nitrogen‐containing monomer, N‐(2‐(5,5‐dimethyl‐1,3,2‐dioxaphosphinyl‐2‐ylamino)ethyl)‐acrylamide (DPEAA), was synthesize and characterized. Flame retardant poly(methyl methacrylate)/organic‐modified montmorillonite (PMMA‐DPEAA/OMMT) nanocomposites were prepared by in situ polymerization by incorporating methyl methacrylate, DPEAA, and OMMT. The results from X‐ray diffraction and transmission electron microscopy (TEM) showed that exfoliated PMMA‐DPEAA/OMMT nanocomposites were formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis, cone calorimeter, and limiting oxygen index (LOI) tests. The synergistic effect of DPEAA and montmorillonite improved thermal stability and reduced significantly the flammability [including peak heat release rates (PHRR), total heat release, average mass loss rate, etc.]. The PHRR of PMMA‐DPEAA/OMMT was reduced by about 40% compared with pure PMMA. The LOI value of PMMA‐DPEAA/OMMT reached 27.3%. The morphology and composition of residues generated after cone calorimeter tests were investigated by scanning electronic microscopy (SEM), TEM, and energy dispersive X‐ray (EDX). The SEM and TEM images showed that a compact, dense, and uniform intumescent char was formed for PMMA‐DPEAA/OMMT nanocomposites after combustion. The results of EDX confirmed that the carbon content of the char for PMMA‐DPEAA/OMMT nanocomposites increased obviously by the synergistic effect of DPEAA and montmorillonite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical properties,flame retardancy,and smoke suppression of lanthanum organic montmorillonite/poly(vinyl chloride) nanocomposites

A dimethyl dioctadecyl ammonium chloride modified organic montmorillonite (OMMT_‐I.44P)/poly(vinyl chloride) (PVC) nanocomposite and anionic‐surfactant‐modified lanthanum organic montmorillonite (La‐OMMT)/PVC nanocomposites (with three different anionic surfactants for the La‐OMMTs) were prepared via melt‐intercalation technology. The effects of the La‐OMMTs and OMMT_‐I.44P on the mechanical properties, flame retardancy, and smoke suppression of PVC were studied. X‐ray diffraction characterization showed that the La‐OMMTs were exfoliated in the PVC matrix. The mechanical properties of the nanocomposites were enhanced by the incorporation of the La‐OMMTs. Cone calorimetry and gas chromatography–mass spectrometry analyses indicated that the incorporation of the La‐OMMTs enhanced the flame retardancy and smoke suppression of the PVC nanocomposites. Scanning electron microscopy photos further showed that the residual char surfaces of La‐OMMT/PVC were all intact and, thus, provided better barriers to energy and smoke transport. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43951.     

有机MMT对高密度聚乙烯改性的研究

采用十二烷基三甲基氯化铵、十六烷基三甲基氯化铵、十六烷基三甲基溴化铵和双十八烷基二甲基氯化铵4种阳离子表面活性剂对钠基蒙脱土(MMT)进行有机化处理,制备了有机MMT(OMMT)。将OMMT与高密度聚乙烯(HDPE)进行熔融插层制备了HDPE／OMMT纳米复合材料,研究了OMMT的层间距同季铵盐烷基链的关系。结果表明,OMMT的层间距随烷基链长度的增加而增大;随着OMMT含量的增加,HDPE／OMMT纳米复合材料的断裂伸长率和拉伸强度降低,弯曲弹性模量增加,弯曲强度出现极大值,使该纳米复合材料的力学性能得到了一定的改善。     

Thermal,mechanical and morphological properties of surface‐modified montmorillonite‐reinforced Viton rubber nanocomposites

Thermal, mechanical and morphological properties of surface‐modified montmorillonite (OMMT)‐reinforced Viton rubber nanocomposites were studied. The surface of montmorillonite was modified with a column chromatography technique using quaternary long‐chain ammonium salt as an intercalant, which resulted in uniform exchange of ions between montmorillonite and the ion‐exchange resin, and increased the d‐spacing to 31.5 Å. This improved d‐spacing was due to the use of an ion‐exchange column of sufficient length (35 cm) and diameter (5 cm) with maximum retention time for exchange of ions. The Viton nanocomposites reinforced with OMMT (3–12 wt%) were prepared using a two‐roll mill and moulded in a compression moulding machine. Tensile strength increased 3.17 times and elongation at break from 500 to 600% for 9 wt% loading of OMMT in comparison to pristine Viton rubber. Thermogravimetric analysis revealed that the presence of OMMT greatly improved the thermal stability. This improvement in properties with increasing OMMT loading was due to insertion of rubber chains between the OMMT plates with good wetting ability. Overall, at an optimum OMMT loading of 9 wt%, the properties of the Viton rubber nanocomposites improved, and subsequently worsened at 12 wt% due to agglomeration of OMMT as revealed by scanning electron microscopy and atomic force microscopy images. © 2013 Society of Chemical Industry     

Influence of intercalated structure on the properties of montmorillonite/high-temperature vulcanized silicone rubber nanocomposites

In this article, montmorillonite/high-temperature silicone rubber hybrid nanocomposites were prepared via melt mixed process. The resulting hybrid nanocomposites were characterized by fourier transform infrared analysis (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), tensile testing and swelling experiment etc. The results proved that the nanocomposites with montmorillonite treated with double octadecyl dimethyl ammonium chloride prepared by melt mixed could form intercalated structure. Double octadecyl dimethyl ammonium chloride has a better effect on enhancing hydrophobicity of montmorillonite layers and expanding the lamellar spacing of montmorillonite than dodecylamine. Furthermore, the mechanical property of the hybrids was improved. The intercalated structure could improve the apparent crosslinking degree of montmorillonite/high-temperature silicone rubber hybrid nanocomposites. Moreover, a novel strategy is proposed to study the effect of intercalated structure on degree of crosslinking.     

Polystyrene nanocomposite materials by in situ polymerization into montmorillonite–vinyl monomer interlayers

A different series of new polystyrene–clay nanocomposites have been prepared by grafting polymerization of styrene with vinyl‐montmorillonite (MMT) clay. The synthesis was achieved through two steps. The first step is the modification of clay with the vinyl monomers, such as N,N‐dimethyl‐n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, n‐octadecyl‐4‐vinylbenzyl‐ammonium chloride, triphenyl‐4‐vinylbenzyl‐phosphonium chloride, and tri‐n‐butyl‐4‐vinylbenzyl‐phosphonium chloride. The second step is the polymerization of styrene with different ratios of vinyl‐MMT clay. The materials produced were characterized by different physical and chemical methods: (1) IR spectra, confirming the intercalation of the vinyl‐cation within the clay interlayers; (2) thermogravimetric analysis (TGA), showing higher thermal stability for PS–nanocomposites than polystyrene (PS) and higher thermal stability of nanocomposites with of phosphonium moieties than nanocomposites with ammonium moieties; (3) swelling measurements in different organic solvents, showing that the swelling degree in hydrophobic solvents increases as the clay ratio decreases; (4) X‐ray diffraction (XRD), illustrating that the nanocomposites were exfoliated at up to a 25 wt % of organoclay content; and (5) scanning electron microscopy (SEM), showing a complete dispersion of PS into clay galleries. Also, transmission electron microscopy (TEM) showed nanosize spherical particles of ～ 150–400 nm appearing in the images. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3739–3750, 2007     

Terpolymer films having semipolar structure: Preparation,wettability, and mechanical properties

A terpolymer, obtained by the free‐radical terpolymerization of 2‐(N,N‐dimethylamino)ethyl methacrylate (DMMA), methyl methacrylate(MMA), and isobutyl methacrylate (IBMA), was allowed to react with hydrogen peroxide, chloroacetic acid, and diethyl sulfate to form the corresponding modified terpolymers: (1) N,N‐dimethyl‐N‐(2‐methacryloyloxyethyl)amine N‐oxide, MMA and IBMA (DMANO series); (2) N‐(carboxymethyl)‐N,N‐dimethyl‐ N‐(2‐methacryloyloxyethyl)ethyl ammonium, MMA and IBMA (CDME series); and (3) N‐(ethyl)‐N,N‐dimethyl‐N‐(2‐methacryloyloxyethyl)ethyl ammonium ethylsulfonate, MMA and IBMA (EDMEES series), respectively. The terpolymer compositions were determined using ¹³C NMR spectrometry. Surface free energies of the terpolymers were estimated by measuring the contact angles of water and methylene iodide on the three series films (DMANO, CDME, and EDMEES), and the effect of the N‐oxide group on wettability was discussed. It was found that the upper surface of the films for the DMANO and CDME series are more hydrophobic than that for the EDMEES series. Notably, elongation to break for the DMANO series was relatively larger than that for the CDME series because of the water bound to the N‐oxide functional group. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1235–1243, 2005     

Mechanical and thermal properties of the hybrid composites of vinylester resin and methacryl‐substituted polysilsesquioxane

Vinylester resin (VER) composed of bisphenol‐A‐based epoxy methacrylate and styrene was cured finally at 120°C with methacryl‐substituted polysilsesquioxane (ME‐PSQ) prepared from 3‐(trimethoxysilyl)propyl methacrylate and tetramethylammonium hydroxide. The dynamic mechanical and thermal properties of the VER/ME‐PSQ 90/10–60/40 hybrid composites were investigated when compared with crosslinked‐VER (C‐VER) and VER/phenyl‐substituted polysilsesquioxane (Ph‐PSQ) 80/20 composite cured at the same condition. As a result, the VER/ME‐PSQ hybrid composites showed much higher storage modulus (E′) at rubbery state than C‐VER and the VER/Ph‐PSQ composite. The E′ of the hybrid composites increased with increasing ME‐PSQ content. Also, coefficient of thermal expansion of the hybrid composites decreased with increasing ME‐PSQ content. The glass transition temperatures and 5% weight loss temperatures of the VER/ME‐PSQ hybrid composites were almost the same as those of C‐VER and the VER/Ph‐PSQ composite. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Crystallization behavior of poly(p‐dioxanone)‐PU/montmorillonite nanocomposites prepared by chain‐extending reaction

Organo‐modified montmorillonites and poly(p‐dioxanone) (PPDO) diol prepolymers were used to prepare Poly(p‐dioxanone)‐PU/organic montmorillonite (PPDO‐PU/OMMT) nanocomposites by chain‐extending reaction. The crystallization behavior and spherulitic morphology of PPDO‐PU/OMMT nanocomposites were investigated by WXRD, differential scanning calorimetry, and polarized optical microscopy. The results show that the regularity of the chain structure plays a dominant role during the crystallization process rather than that of OMMT content and its dispersion status in PPDO matrix. With similar molecular weight and same OMMT content, PPDO‐PU/OMMT nanocomposite, which derived from lower molecular weight PPDO prepolymer, exhibits lower crystallization rate, melting point, and crystallinity. The influence of the clay content on the crystallization behavior highly depends on its dispersing state. The nucleating effect of OMMT can be only observed at high loading percentage. For the nanocomposites with low clay loading percentage, the retarding effect of exfoliated platelets on the chain‐ordering into crystal lamellae became the key factor. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of nano‐organomontmorillonite on the viscoelasticity of the poly(trimethylene terephthalate)/glass fiber/organomontmorillonite hybrid nanocomposites materials

The influences of organically modified montmorillonite (OMMT) on the viscoelasticity of poly(trimethylene terephthalate)/glass fiber/OMMT (PTT/GF/OMMT) hybrid nanocomposite materials at liquid, elastic and glassy states, respectively, were investigated by using the rotational rheometer and dynamic mechanical analyzer (DMA). The viscoelasticity results suggest that OMMT has many important influences on the structure, modulus and toughness of the hybrid nanocomposite materials. At melton state, the shear‐thinning phenomena of the hybrid composite melts become remarkable with increasing OMMT content. At low frequency, the shear storage modulus (G′) and shear loss modulus (G″) of the melts increase with increasing OMMT content. The melt's elastic response increases by OMMT, and OMMT improves the creep resistance of the melts; in addition, the stress relaxation of the hybrid composite melts become slow with increasing OMMT content, and the stress leavings becomes much higher with increasing OMMT content. At glassy state, the storage modulus of the hybrid nanocomposites increases with increasing OMMT content, while the materials' loss modulus increases first and then decreases with increasing OMMT content; therefore, OMMT nanosheets have reinforcement effect on the composites, and it also has definite toughening effect on the hybrid composite when the OMMT content is no >2 wt%. At rubbery state, the hybrid composites show lower decreasing storage modulus but have lower cold‐crystallization ability than that of pure PTT and PTT/GF composite. POLYM. COMPOS., 35:795–805, 2014. © 2013 Society of Plastics Engineers