Preparation of transparent PMMA/Fe(IO3)3 nanocomposite films from microemulsion polymerization

Polymethyl methacrylate (PMMA)/Fe(IO₃)₃ nanocomposite thin films are obtained by in situ particle generation in microemulsions and subsequent photopolymerization of a mixture containing methyl methacrylate, trimethylolpropane triacrylate, and crystallized iron iodate (Fe(IO₃)₃) nanorods. Hyper‐Rayleigh scattering measurements combined with X‐ray diffraction, transmission electron microscopy, and dynamic light scattering are first used to probe in situ the crystallization kinetics of iron iodate nanorods in water‐in‐oil microemulsions prepared with methyl methacrylate as the oil phase and marlophen NP12 as a surfactant. Trimethylolpropane triacrylate is then added as a crosslinker before spin‐coating. Films are deposited on glass substrates for the nonlinear optical characterizations and on silicon wafers for the piezoelectric and mechanical measurements. Nanocomposite films treated by corona discharge are finally characterized through optical microscopy, laser Doppler vibrometry, and Brillouin spectroscopy. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1203‐1211, 2013     

Improvement of the thermal transport performance of a poly(vinylidene fluoride) composite film including silver nanowire

The miniaturization trend of electronic devices requires that components have a high heat dissipation in industrial applications and in daily life. In this context, a highly thermally conductive film was fabricated with silver nanowire (AgNW) and poly(vinylidene fluoride) (PVDF) with a bar‐coating method. The thermal transport performance and mechanism of the AgNW/PVDF composite film were investigated. The through‐plane and in‐plane thermal conductivity of the AgNW/PVDF composite film reached 0.31 and 1.61 W m^?1 K^?1, respectively; these values far exceeded those of the pristine PVDF film. The experiment illustrated that the thermally conductive pathways formed successfully in the PVDF substrate with the addition of AgNW, and the heat tended to transfer along the thermally conductive pathway rather than along the PVDF substrate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43554.     

Positron annihilation and other experimental studies on polycarbonate/MPDMAPP nanocomposite

The composite films of polycarbonate (PC) filled with 1‐(4‐methylphenyl)‐3‐(4‐N,N‐dimethylaminophenyl)‐2‐propen‐1‐one (MPDMAPP) were prepared by solution casting. The FT‐IR results of the prepared films confirmed the hydrophobic and dipole‐dipole interaction between PC and MPDMAPP, which is a major driving force for the formation of charge transfer complex (CTC). UV–Vis absorption spectra showed three peaks and the optical band gap E_g for pure PC is 4.31 eV which decreased to 4.1 eV after 15 wt % doping. The fluorescence spectral results show a strong emission and quenching in the wavelength region 510 to 550 nm for 408 nm excitation due to increase in amorphousness, which is observed in X‐ray diffraction (XRD) results. The decrease in ortho‐positronium (o‐Ps) lifetime τ₃ and corresponding intensity I₃ from positron annihilation lifetime spectroscopy (PALS) and the S‐parameter from Doppler broadening measurements show both inhibition and quenching of Ps formation in the PC/MPDMAPP composite due to the presence of dimethylamino N(CH₃)₂ group. The mechanical properties such as Young's modulus, tensile strength, and stiffness increase with doping concentration and confirmed that the composite films are mechanically stable. The growth of nanostructures of MPDMAPP within PC films is studied with SEM and TEM images and confirms the uniform dispersion and interaction between the functional groups of PC and MPDMAPP. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42053.     

Temperature dependent dielectric properties of self‐standing and flexible poly(vinylidene fluoride) films infused with Er3+ doped GeO2 and SiO2 nanoparticles

The synthesis of Er³⁺@GeO₂ and Er³⁺@SiO₂ nanoparticle impregnated self‐standing poly(vinylidene fluoride) films by a facile solution casting technique has been reported. The prepared films were thoroughly characterized using X‐ray diffraction technique, field emission scanning electron microscopy, and transmission electron microscopy. The optical properties were evaluated using UV–Vis spectroscopy. Detailed study on the temperature dependent dielectric properties of the composite films with different Er³⁺ content were also investigated to establish the electrical properties of the same, which revealed the presence of different relaxation processes, namely, and ρ. Due to the smaller size, Er³⁺@SiO₂ was found to disperse better in the PVDF matrix than Er³⁺@GeO₂, which resulted in higher dielectric constant of the former at 300 K. At higher temperature (403 K), the behavior was reversed due to the formation of larger sized low mobility complexes. An investigation on ac conductivity proved the conduction mechanism for neat as well as composite PVDF films to follow the Correlated Barrier Hopping model. The loading of Er³⁺@GeO₂ and Er³⁺@SiO₂ nanoparticles in the PVDF matrix significantly enhances the dielectric properties without losing the flexibility of the composite films. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44016.     

Novel,promising, and broadband microwave-absorbing nanocomposite based on the graphite-like carbon nitride/CuS

In this study, a broadband, intense, novel, and promising microwave-absorbing nanocomposite was prepared using graphite-like carbon nitride (g-C₃N₄)/CuS suspended in poly(methyl methacrylate) (PMMA) medium. The g-C₃N₄ nanosheets were synthesized by heating the urea as well as the CuS nanoparticles, and g-C₃N₄/CuS nanocomposites were prepared using a solvothermal method and then were separately molded by a PMMA solution to investigate their microwave-absorbing characteristics. The Fourier transform infrared and X-ray powder diffraction were used to characterize the g-C₃N₄, CuS, and CuS/g-C₃N₄ nanostructures, which confirmed that the pure structure of the nanomaterials has been synthesized. The optical properties of the nanostructures were also investigated by diffuse reflection spectroscopy analysis. Accordingly, the Kubelka–Munk theory suggested significant narrow band gap for g-C₃N₄/CuS nanocomposite (0.27 eV), facilitating electron jumping and conductive loss. The morphology of the structures was examined using field emission scanning electron microscopy micrographs, illustrating that the uniform hexagonal structures of the CuS nanoplates have been formed and the CuS two-dimensional structures were uniformly distributed on the g-C₃N₄ nanosheets. Finally, the microwave-absorbing properties of the CuS, g-C₃N₄, and g-C₃N₄/CuS were investigated by PMMA as a host. The microwave-absorbing properties were evaluated using a vector network analyzer. The results illustrated that the maximum reflection loss of the g-C₃N₄/PMMA nanocomposite was −71.05 dB at 14.90 GHz with a thickness of 2.00 mm, demonstrating a 1.70 GHz bandwidth >30 dB, as well as g-C₃N₄/CuS/PMMA nanocomposite absorbed 7.30 GHz bandwidth of more than 10 dB with a thickness of 1.80 mm along the x- and ku-band frequency. The obtained results introduced the PMMA as a capable microwave-absorbing substrate. Besides, the g-C₃N₄/CuS/PMMA nanocomposite demonstrated metamaterial property and abundant attenuation constant. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48430.     

Synthesis of poly(butyl acrylate)—laponite nanocomposite nanoparticles for improving the impact strength of poly(lactic acid)

This work aims at preparing and characterizing poly(butyl acrylate) (PBA)—laponite (LRD) nanocomposite nanoparticles and nanocomposite core (PBA‐LRD)‐shell poly(methyl methacrylate) (PMMA) nanoparticles, on the one hand, and the morphology and properties of poly(lactic acid) (PLA)‐based blends containing PBA‐LRD nanocomposite nanoparticles or (PBA‐LRD)/PMMA core–shell nanoparticles as the dispersed phase, on the other hand. The PBA and (PBA‐LRD)/PMMA nanoparticles were synthesized by miniemulsion or emulsion polymerization using LRD platelets modified by 3‐methacryloxypropyltrimethoxysilane (MPTMS). The grafting of MPTMS onto the LRD surfaces was characterized qualitatively using FTIR and quantitatively using thermogravimetric analysis (TGA). The amounts of LRD in the PBA‐LRD nanocomposites were characterized by TGA. The PBA/PMMA core–shell particles were analyzed by ¹H‐NMR. Their morphology was confirmed by SEM and TEM. Mechanical properties of (PBA‐LRD)/PLA blends and (PBA‐LRD)/PMMA/PLA ones were tested and compared with those of the pure PLA, showing that core–shell particles allowed increasing impact strength of the PLA while minimizing loss in Young modulus and tensile strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film for antibacterial application

Iodine-loaded poly(silicic acid) gellan nanocomposite film was fabricated and evaluated for antibacterial properties. Poly(silicic acid) nanoparticles were synthesized by condensation of silicic acid under alkaline conditions in the presence of polyvinyl pyrrolidone, phosphate ions, and molecular iodine. The nanoparticles were incorporated into gellan dispersion to prepare gellan nanocomposite film using the solvent casting method. The nanocomposite films were characterized by Fourier transformed infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction studies. The results of characterization studies indicated improved thermal stability and an increase in the degree of crystallinity. The scanning electron micrographs and energy dispersive X-ray spectrum confirmed the uniform dispersion of silica and iodine in the nanocomposite films. The analysis of physical and mechanical properties revealed the enhanced tensile strength, moisture resistance, and higher folding endurance of poly(silicic acid) gellan nanocomposite films as compared to gellan film. Further, the iodine-loaded poly(silicic acid) gellan nanocomposite films showed good antibacterial activity against Staphylococcus aureus and Escherichia coli and effective mucoadhesive strength. The results indicate that iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film can be used for potential antibacterial applications in pharmaceuticals.     

SiO2-modified nanocomposite nanofiltration membranes with high flux and acid resistance

Thin-film nanocomposite (TFN) nanofiltration (NF) membranes with superior properties were prepared using hydrophilic SiO₂ (HGPN-SiO₂) nanoparticles as the inorganic modifying monomer by an interfacial polymerization (IP) process. The effects of HGPN-SiO₂ on the morphology and surface properties of the prepared NF membranes were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, atomic force microscopy, surface zeta potential, and static contact angle. The addition of HGPN-SiO₂ can effectively improve the permeate flux of the NF membranes. When the HGPN-SiO₂ concentration in the aqueous phase was 0.08 wt %, the permeate flux of the TFN-NF membrane was twice that of the pure NF membrane. Furthermore, the acid resistance of the TFN-NF membrane was clearly improved with the addition of HGPN-SiO₂. Under neutral conditions, the TFN-NF membrane showed superior flux and salt rejection stability in a long-running operation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47436.     

Fabrication of superhydrophobic transparent cyclic olefin copolymer (COC)-SiO2 nanocomposite surfaces

A superhydrophobic cyclic olefin copolymer (COC) nanocomposite coating was produced with a very simple and easy method. Self-cleaning superhydrophobic COC surfaces were obtained by only adding surface hydrophobized SiO₂ nanoparticles by dip coating method. The influence of concentration of SiO₂ and the coating temperatures on the wettability of the surfaces were investigated. The surface wettability of the coatings was examined with the contact angle measurements and the surface roughness and morphology were analyzed by using atomic force microscope and scanning electron microscopy analysis. Surfaces with certain amounts of COC and SiO₂ showed superhydrophobic character with high water contact angle of 169⁰. Also, the obtained superhydrophobic surfaces show superior water repellent, high transparency, and self-cleaning characteristics.     

Transparent dispensible high‐refractive index ZrO2/epoxy nanocomposites for LED encapsulation

In this study, we report a facile ex situ approach to preparing transparent dispensible high‐refractive index ZrO₂/epoxy nanocomposites for LED encapsulation. Highly crystalline, near monodisperse ZrO₂ nanoparticles (NPs) were synthesized by a nonaqueous approach using benzyl alcohol as the coordinating solvent. The synthesized particles were then modified by (3‐glycidyloxypropyl)trimethoxysilane (GMS) ligand. It was found that, with tiny amount of surface‐treating ligand, the modified ZrO₂ NPs were able to be easily dispersed in a commercial epoxy matrix because of the epoxy compatible surface chemistry design as well as the small matrix molecular weight favoring mixing. Transparent thick (1 mm) ZrO₂/epoxy nanocomposites with a particle core content as high as 50 wt % and an optical transparency of 90% in the visible light range were successfully prepared. The refractive index of the prepared composites increased from 1.51 for neat epoxy to 1.65 for 50 wt % (20 vol %) ZrO₂ loading and maintained the same high‐Abbe number as the neat epoxy matrix. Compared with the neat epoxy encapsulant, an increase of 13.2% in light output power of red LEDs was achieved with the 50 wt % ZrO₂/epoxy nanocomposite as the novel encapsulant material. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3785–3793, 2013     

Preparation and characterization of polybutylene‐succinate/poly(ethylene‐glycol)/cellulose nanocrystals ternary composites

Ternary composites were prepared by twin screw extrusion from polybutylene‐succinate (PBS), poly(ethylene‐glycol) (PEG), and cellulose nanocrystals (CNC). The aim of the work is to improve the physical–mechanical properties of PBS by the addition of CNC. A PEG/CNC masterbatch was prepared in order to achieve a good dispersion of hydrophilic CNC in the hydrophobic PBS. The influence of the nanoparticle content on the polymer properties was studied. Regarding the thermal properties fractioned crystallization phenomena of PEG was observed during cooling from the melt. No significant nucleating effect of the nanocellulose was observed. The material containing 4 wt % of CNC showed the best mechanical performance among the nanocomposites studied due to the combination of high modulus and elongation at break with a low detrimental in strength compared with the PBS/PEG blend. Moreover, no nanocellulose agglomerations were observed in its FESEM micrograph. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43302.     

Effect of shell phase composition on the dielectric property and energy density of core-shell structured BaTiO3 particles modified poly(vinylidene fluoride) nanocomposites

Dielectric nanocomposites have attracted much attention due to their wide applications in electronics and electrical industry. Recently, incorporating core-shell nanoparticles into polymer matrix to improve the dielectric properties of nanocomposites has been widely reported. Tailoring the interfacial region between the polymer and the nanoparticles plays a crucial role in achieving the desired dielectric and energy storage properties of nanocomposites. However, the effect of shell structure in the interface region on the dielectric and energy storage properties is rarely studied. Based on this, core-shell BaTiO₃ nanoparticles with two different shell polymers, a “hard-soft” copolymer of methyl methacrylate and butyl acrylate (P[MMA-BA]) and a “hard” homopolymer of methyl methacrylate (PMMA), were prepared in this paper. The effect of core-shell BaTiO₃ nanoparticles with different shell structures on the dielectric and energy storage properties of poly(vinylidene fluoride) (PVDF) was investigated in depth. Due to the formation of a tight interfacial region between P(MMA-BA)@BT and PVDF matrix, P(MMA-BA)@BT/PVDF nanocomposites not only have low dielectric loss but also higher energy efficiency than PMMA@BT/PVDF nanocomposites. This study suggests a potential strategy that fabricating a “hard-soft” copolymer shell on BaTiO₃ surface can obtain desirable energy storage efficiency than the single “hard” shell structure in dielectric nanocomposites.     

Thermal conductivity of polyimide/boron nitride nanocomposite films

The thermal conductivity of polyimide/boron nitride (PI/BN) nanocomposite thin films has been studied for two sizes of BN nanofillers (40 and 120 nm) and for a wide range of content. A strong influence of BN particle size on the thermal conduction of PI has been identified. In the case of the largest nanoparticles (hexagonal‐BN), the thermal conductivity of PI/h‐BN (120 nm) increases from 0.21 W/mK (neat PI) up to 0.56 W/mK for 29.2 vol %. For the smaller nanoparticles (wurtzite‐BN), PI/w‐BN (40 nm), we observed two different behaviors. First, we see a decrease until 0.12 W/mK for 20 vol % before increasing for higher filler content. The initial phenomenon can be explained by the Kapitza theory describing the presence of an interfacial thermal resistance barrier between the nanoparticles and the polymer matrix. This is induced by the reduction in size of the nanoparticles. Modeling of the experimental results allowed us to determine the Kapitza radius a_K for both PI/h‐BN and PI/w‐BN nanocomposites. Values of a_K of 7 nm and >500 nm have been obtained for PI/h‐BN and PI/w‐BN nanocomposite films, respectively. The value obtained matches the Kapitza theory, particularly for PI/w‐BN, for which the thermal conductivity is expected to decrease compared to that of neat PI. The present work shows that it seems difficult to enhance the thermal conductivity of PI films with BN nanoparticles with a diameter <100 nm due to the presence of high interfacial thermal resistance at the BN/PI interfaces. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42461.     

Preparation and properties of hydrophobic poly(vinylidene fluoride)–SiO2 mixed matrix membranes for dissolved oxygen removal from water

The application of the membrane method for removing dissolved oxygen (DO) from water on the laboratory scale was studied. Flat mixed matrix membranes were composed of poly(vinylidene fluoride) (PVDF) and hydrophobic nanosilica particles, which were used to improve the DO removal process. The SiO₂ particles were modified by a silane coupling agent and examined by Fourier transform infrared spectroscopy. It was shown that the surface of the SiO₂ particles was bonded to hydrophobic long‐chain alkane groups through chemical bonding. The effects of adding SiO₂ particles on the membrane properties and morphology were examined. The results show that the porosity and pore size of the membrane were affected by the introduction of SiO₂ particles, and the cross‐sectional morphology of the PVDF composite membranes changed from fingerlike macrovoids to a spongelike structure. The membrane performance of DO removal was evaluated through the membrane unit by a vacuum degassing process. It was found that the SiO₂/PVDF hybrid membranes effectively improved the oxygen removal efficiency compared with the original PVDF membranes. The maximum permeation flux was obtained when the loading amount was 2.5 wt %. The effect of the downstream vacuum level was also investigated. The experimental results show that the SiO₂/PVDF hybrid membranes had superior performances and could be an alternative membrane for removing DO from water. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40430.     

A model for water vapor permeability reduction in poly(lactic acid) and nanoclay nanocomposites

Poly(lactic acid) (PLA) is used in packaging applications, but its moisture barrier properties are inferior to poly(ethylene terephthalate) and polystyrene. One objective of the study was to improve these by dispersing nanoclay in PLA. It was found that Cloisite 30B nanoclay showed the best dispersion based on both permeability and transmission electron microscopy results. Compression molded nanocomposite films were amorphous, and moisture permeability measurements revealed that, at the highest loading level of 5.3 vol % organoclay, permeability was reduced by 69% compared to neat PLA. Additionally, independent experiments demonstrated that moisture solubility in the polymer remains unchanged even as solubility in the nanocomposite increases with increasing clay content. A second objective was to explain the measured permeability reduction. A new model is proposed where both the mass flux and area for mass transfer are reduced due to a tortuous path around the impermeable barriers. It is shown that the permeability decreases by a factor of where h/t is the aspect ratio of the nanoplatelets, and ? is their volume fraction. Model predictions agree quantitatively with the measured permeability values when data are obtained as a function of filler volume fraction, temperature of measurement, and the concentration driving force. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46506.     

3D printing of copper particles and poly(methyl methacrylate) beads containing poly(lactic acid) composites for enhancing thermomechanical properties

Poly(lactic acid) (PLA) composite filaments with different copper (Cu) contents as high as 40 and 20 wt% of poly(methyl methacrylate) (PMMA) beads have been fabricated by twin-screw extruder for 3D printing. A fused-deposition modeling (FDM) 3D printing technology has been used to print the PLA composites containing hybrid fillers of Cu particles and PMMA beads. The morphology, mechanical, and thermal properties of the printed PLA composites were investigated. The tensile strength was slightly decreased, but storage modulus and thermal conductivity of PLA composites were significantly improved by adding Cu particles in the presence of PMMA beads. The PLA composites with hybrid fillers of 40 wt% of Cu particles and 20 wt% of PMMA beads resulted in thermal conductivity of 0.49 W m⁻¹ K⁻¹ which was three times higher than that of the bare PLA resin. The facilitation of the segregated network of high-thermally conductive Cu particles with the PMMA beads in PLA matrix provided thermally conductive pathways and resulted in a remarkable enhancement in thermal conductivity.     

Effects of silica on the morphology,structure, and properties of thermoplastic cassava starch/poly(vinyl alcohol) blends

Thermoplastic cassava starch (TPS)/poly(vinyl alcohol) (PVA)/silica (SiO₂) composites were prepared by a melt‐mixing method. The effects of the content and surface properties of SiO₂ on the processing, mechanical properties, thermal stability, morphology, and structure of the TPS/PVA/SiO₂ composites were investigated. With increasing SiO₂ content, the plasticizing times of the TPS/PVA/SiO₂ composites were shortened. After the SiO₂ surface was treated with a silane coupling agent (KH550), the plasticizing times of the TPS/PVA/SiO₂ composites decreased significantly. The tensile strength, elongation at break, and Young's modulus of the TPS/PVA/SiO₂ composites increased. The mechanical properties of the TPS/PVA/SiO₂ composites containing treated SiO₂ were higher than those with untreated SiO_2. The thermal decomposition temperatures of the TPS/PVA/SiO₂ composites were improved with the addition of SiO₂. The presence of inorganic fillers was beneficial to the improvement of the thermal stability of the polymers. The reaction between the treated SiO₂ and the starch molecules was beneficial to the formation of more stable structures. The treated SiO₂ indicated good interfacial adhesion and uniform dispersion in the matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44020.     

Preparation and testing of Nafion/titanium dioxide nanocomposite membrane electrode assembly by ultrasonic coating technique

Membrane electrode assemblies with Nafion/nanosize titanium dioxide (TiO₂) composite membranes were manufactured with a novel ultrasonic‐spray technique (UST) and tested in proton exchange membrane fuel cell (PEMFC). The structures of the membranes were investigated by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and thermogravimetric analysis. The composite membranes gained good thermal resistance with insertion of TiO₂. The SEM and XRD techniques have proved the uniform and homogeneous distribution of TiO₂ and the consequent enhancement of crystalline character of these membranes. The existence of nanometer size TiO₂ has improved the thermal resistance, water uptake, and proton conductivity of composite membranes. Gas diffusion electrodes were fabricated by UST. Catalyst loading was 0.4 (mg Pt) cm^?2 for both anode and cathode sides. The membranes were tested in a single cell with a 5 cm² active area operating at the temperature range of 70°C to 110°C and in humidified under 50% relative humidity (RH) conditions. Single PEMFC tests performed at different operating temperatures indicated that Nafion/TiO₂ composite membrane is more stable and also performed better than Nafion membranes. The results show that Nafion/TiO₂ is a promising membrane material for possible use in PEMFC at higher temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40541.     

Effects of interlayer density and surfactant on coupled thermal stress and moisture absorption in modified montmorillonite/polypropylene nanocomposite

Modified montmorillonite/polypropylene nanocomposites (NCs) are increasingly used in industrial applications such as subsea pipelines because hexadecyltrimethyl ammonium montmorillonite (HDTMA⁺-Mt) enhances thermomechanical and barrier properties of the amorphous polymer. Two coupled physics of moisture adsorption and thermal loading are investigated. Molecular dynamics simulates HDTMA⁺-Mt polymer NC using three force fields including polymer consistent force field and condensed-phase optimized molecular potentials, and embedded-atom method. Mechanical properties and self-diffusion coefficient are investigated at temperature levels of 100 and 298 K, and water content of 0.021 and 0.133 g/g. These properties are evaluated at 1.0 atm pressure for four different volume fractions (vol%) of the HDTMA⁺-Mt. The modeling procedure is verified by obtaining the glass transition temperature (T_g) of the NC by scanning the temperature from 200 K (glassy state) up to 325 K (rubbery state). It is observed that the T_g is very close to the experimental value available in the literature. The result of the modeling shows that the increase of clay content of the NC decreases the self-diffusion coefficient of the material. It is seen that the clay nanoparticle can significantly hinder the degradation of mechanical properties of the NC even when both temperature and water content increase.     

Melt spinning and drawing of polyethylene nanocomposite fibers with organically modified hydrotalcite

Fibers of high density polyethylene (HDPE)/organically modified hydrotalcite (LDH) were produced by melt intercalation in a two‐step process consisting of twin‐screw extrusion and hot drawing. The optimum drawing temperature was 125°C at which the draw ratios up to 20 could be achieved. XRD analysis revealed intercalation with a high degree of exfoliation for the composites with 1–2% of LDH. Higher thermal stability of nanofilled fibers was confirmed by TGA analysis. DSC data indicated that dispersed LDH particles act as a nucleating agent. Crystallization kinetics of the HDPE matrix in the composite fibers is characterized by two transition temperatures, that is, for Regimes I/II at 123°C and for Regimes II/III ranging between 114–119°C as a function of the nanocomposite composition. Fibers with 1–2% of LDH show for the drawing ratios up to 15 a higher elastic modulus, 9.0–9.3 GPa (with respect to 8.0 GPa of the neat HDPE), maintain tensile strength of 0.8 GPa and deformation at break of 20–25%. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40277.