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The efficient inclusion of GNPs (graphene nanoplatelets) as an effective nano‐fillers for green polymer matrices produced with 28% of carbon originating from biomass tends to significantly improve mechanical and thermal properties. In the present work, green epoxy nanocomposites with low loading of (0.1, 0.25, and 0.5) wt% of the GNPs were made using a solution blending technique using acetone as the solvent. In mechanical stirring, the ultrasonic bath was used to ensure the efficient dispersion of GNPs within green epoxy. The resulting nanocomposites were comprehensively characterized and compared to unfilled green epoxy. Different tools were used to appraise morphological, thermal, thermo‐mechanical, and mechanical behavior. The results confirmed through FE‐SEM showed an optimal dispersion of GNPs with nanocomposites. The thermal degradation temperature (Td) of GNPs curve with 0.25 wt% loading was shifted toward higher temperature (from 336°C to 342°C) due to low percentage of loading of GNPs which showed an enhance thermal stability of polymer matrix with 0.25 wt% loading. The mechanical results were also in lined with previously published literature, in the tensile test 6.45% and hardness 13.3% increment was achieved. Overall, the results underscored significant improvements in green nanocomposite performance with low wt% of GNPs. Highlights: The study focuses on development and characterization of green epoxy nanocomposites, which utilize environmentally friendly materials as a matrix, highlighting the significance of sustainability.The study explores effects of low loading of GNPs in green epoxy nanocomposites. The results demonstrate significant improvements in mechanical and thermal properties with optimized presence of GNPs. This investigation provides insights into optimal amount of GNPs required to achieve improved properties.Research evaluates multifaceted analysis provides a holistic understanding of performance enhancements achieved through inclusion of GNPs. [ABSTRACT FROM AUTHOR]

The matrix's dielectric constant can be reduced with little quantity of POSS because of its unique cage skeleton structure and remained air in the caves. After epoxied, epoxy polyhedral oligomeric silsesquioxane (EPPOSS) promoted its compatibility with bisphenol A cyanate ester (BADCy) and bisphenol A benzoxazine (BA-a) by a curing processing between BADCy and EPPOSS and further copolymerizing with ring opened BA-a. Consequently, two Tgs were observed in the integrated nanocomposite, attributing to the BADCy homopolymer and the BADCy and BA-a copolymer. The more quantity of EPPOSS, the lower dielectric constants of nanocomposites achieved, as well as the initial storage modulus and Tgs due to the flexible ether bonds generated by EPPOSS. With up to 15 wt.% EPPOSS, the dielectric constant decreased to 2.72 at 1 MHz. The toughness and thermal stability of the nanocomposites also enhanced through increased the crosslinking density and inorganic Si–O–Si framework of EPPOSS. [ABSTRACT FROM AUTHOR]

In this study thermal and structural properties characterization were performed for prepared ultra-high molecular weight polyethylene/carbon nanotube (UHMWPE/CNT) nanocomposite sheets by using a melt compounding method. The sheets were prepared by using six types of CNTs; pristine single walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), oxidized- SWCNT and MWCNT, and amide- SWCNT and MWCNT. Thermogravimetric analysis results revealed that the addition of CNTs increased the nanocomposites thermal stability (17 °C) being produced by P-MWCNT. Differential scanning calorimetry and x-ray diffraction (XRD) results show no significant crystalline structure changes compared with the pure polymer, and increase in crystallinity (4%) for O-SWCNTs additions (4%). Scanning electron microscope images showed improved bridging in the polymer matrix by using oxidized and functionalized CNTs compared with pristine CNTs. These findings suggest that the durability of UHMWPE is enhanced by this nano-modification method, improving its suitability for many lightweight, high strength material applications. [ABSTRACT FROM AUTHOR]

The polydimethylsiloxane/nano-graphite (PDMS-NG) nanocomposites were prepared via a two rolled mixing mill and subjected to characterization using techniques such as Transmission Electron Microscopy (TEM), stress-strain analysis during elongation, as well as thermal properties including Thermo-Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The transition temperature was observed to be below -70°C for PDMS nanocomposites reinforced with Nano-Graphite (NG). The thermogram from the thermo-gravimetric analysis indicated that at 10%, 20%, 30%, and 50% weight loss, the temperatures for PDMS nanocomposites were higher compared to unfilled PDMS. These findings suggest a substantial improvement in the thermal stability of PDMS-NG nanocomposites. [ABSTRACT FROM AUTHOR]

Outstanding high-temperature resistance, thermal stability, and dielectric properties are fundamental for dielectric materials used in harsh environments. Herein, TiO2 nanoparticles are decorated on the surface of BN nanosheets by internal crosslinking between polydopamine (PDA) and polyethyleneimine (PEI), forming three-dimensional novel nanohybrids with a rough surface. Then, an ether nitrile (PEN) matrix is introduced into the polyarylene to form polymer-based nanocomposite dielectric films. Meanwhile, the structure and micromorphology of the newly prepared nanohybrids, as well as the dielectric and thermal properties of PEN nanocomposites, are investigated in detail. The results indicate that TiO2 nanoparticles tightly attach to the surface of BN, creating a new nanohybrid that significantly enhances the comprehensive performance of PEN nanocomposites. Specifically, compared to pure PEN, the nanocomposite film with a nanofiller content of 40 wt% exhibited an 8 °C improvement in the glass transition temperature (Tg) and a 162% enhancement in the dielectric constant at 1 kHz. Moreover, the dielectric constant–temperature coefficient of the nanocomposite films remained below 5.1 × 10−4 °C−1 within the temperature range of 25–160 °C, demonstrating excellent thermal resistance. This work offers a method for preparing highly thermal-resistant dielectric nanocomposites suitable for application in elevated temperature environments. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites, which combine the advantages of polymers and fillers, are widely used in the field of automobile and aviation. Polyimine (PI) is an emerging thermoset material with remarkable properties, such as malleability, recyclability, and self-healing. Silicon carbide nano-whiskers (SiCw), as a cheap and high-hardness filler material, are chosen to enhance the properties of polyimine matrix. Silicon carbide nano-whisker-reinforced polyimine (PI-SiCw) nanocomposites were successfully fabricated by heat pressing, which was confirmed by FTIR and XPS tests. According to the results of mechanical tests, the mechanical properties of PI-SiCw nanocomposites were obviously improved. For example, with the addition of 0.5% SiCw, bending strength and bending elongation at break can be simultaneously increased by 33% and 148%, respectively. Surprisingly, the impact strength of PI-SiCw nanocomposites with 2% SiCw was increased by 154% compared to the matrix. SEM and EDS tests showed that the evenly distributed SiCw in the polyimine matrix enhanced the mechanical properties of PI-SiCw nanocomposites according to the mechanism of whiskers pulling out and the bridging principle. According to the TGA test results, the PI composites with SiCw retain a higher weight percentage at 800 °C. The reason was the combined effect of the good thermal stability of SiCw and their strong interactions with the PI matrix. As a result, introducing SiCw into the PI matrix imparts a slight improvement in thermal stability. This article presents an avenue of cost-effective research to enhance the mechanical properties of polyimine composites. [ABSTRACT FROM AUTHOR]

In this work, nanocomposites of polyvinyl chloride poly(epichlorohydrin-co-ethylene oxide)(ECO)/organoclay were prepared via melt processing and various parameters including nanoclay and rubber content (ECO) as well as rotor speed were tuned to find the optimum formulation for the highest thermal stability. The prepared products were characterized by X-ray diffraction as well as thermogravimetric analysis (TGA), derivative thermogravimetric (DTG) and differential thermal analysis XRD results showed that rotor speeds higher than 70 r/min are crucial for obtaining highly intercalated products with good thermal stability. From DTG analyses, it was observed that at lower concentrations of rubber, the rate of mass loss is higher which results in faster dehydrochlorination of the composite. The sample prepared with 2 phr OMMT, 30 phr rubber, and 70 r/min rotor speed showed the highest thermal stability. The selected nanocomposite showed the first weight loss at 294 ℃. Results of this research showed that even a slight change in each parameter has a great influence on thermal properties of the nanocomposites. The hydrogen bonding mode between ECO and organoclay were estimated by theoretical calculations using GAUSSIAN software. From the obtained results, the miscibility of OMMT and ECO polymer is related to the hydrogen bonds which are more preferred at chlorine atom of ECO polymer. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites based on PP/Cu were obtained by the combining of ex-situ casting solution and hot pressing methods. The structure of polymer nanocomposites was characterized by XRD, SEM, EDS, AFM and FT-IR spectroscopy analysis. The thermal properties were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was found that the addition of copper nanoparticles to the PP polymer matrix increases the thermal stability of the polymer, and this thermal stability reaches its maximum value at 3% content of copper nanoparticles in the polymer. The reason for the increase in the thermal properties of nanocomposites is associated with the formation of a more perfect, dense and ordered structure of PP-based composites and the fact that nanoparticles play the role of a nucleus of crystallization for polymer matrices. [ABSTRACT FROM AUTHOR]

This experimental study is devoted to the analysis of Multiwall Carbon Nanotubes (MWCNTs) and graphitic carbon nitride (g-C3N4) nanofiller reinforced epoxy hybrid nanocomposites using casting technique. Different weight fraction of nanofiller such as 0.5, 1, 3, and 5% were developed. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used to confirm the morphological behaviors of developed hybrid nanocomposites and the agglomeration free uniform dispersion of nanofillers in epoxy matrix. The effects of reinforcements on the tensile, flexural, and water absorption properties of epoxy hybrid nanocomposites were also investigated. The results were tabulated and recorded. It was observed that the increase in reinforcement is found to be increased the behaviors of epoxy hybrid nanocomposites. [ABSTRACT FROM AUTHOR]

Biodegradable polymers play a significant role in medical applications, especially internal devices because they can be broken down and absorbed into the body without producing harmful degradation products. In this study, biodegradable polylactic acid (PLA)-polyhydroxyalkanoate (PHA)-based nanocomposites with various PHA and nano-hydroxyapatite (nHAp) contents were prepared using solution casting method. Mechanical properties, microstructure, thermal stability, thermal properties, and in vitro degradation of the PLA-PHA-based composites were investigated. PLA-20PHA/5nHAp was shown to give the desired properties so it was selected to investigate electrospinnability at different applied high voltages. PLA-20PHA/5nHAp composite shows the highest improvement of tensile strength at 36.6 ± 0.7 MPa, while PLA-20PHA/10nHAp composite shows the highest thermal stability and in vitro degradation at 7.55% of weight loss after 56 days of immersion in PBS solution. The addition of PHA in PLA-PHA-based nanocomposites improved elongation at break, compared to the composite without PHA. PLA-20PHA/5nHAp solution was successfully fabricated into fibers by electrospinning. All obtained fibers showed smooth and continuous fibers without beads with diameters of 3.7 ± 0.9, 3.5 ± 1.2, and 2.1 ± 0.7 µm at applied high voltages of 15, 20, and 25 kV, respectively. [ABSTRACT FROM AUTHOR]

Polycarbonate (PC) /graphene nanocomposite was prepared using multilayer graphene (MLG) with loadings of 0.5, 1, and 3 wt% via melt mixing process. Morphological, structural, and thermal properties of the PC/MLG nanocomposites are investigated to look into the influence of MLG on the nanocomposite. A significant increase (∼6.4°C) in glass transition temperature is observed upon the addition of 3 wt% of MLG into the polycarbonate matrix. This increase in glass transition temperature may be due to the interaction between the MLG and polycarbonate polymer matrix. The specific heat capacity of pure PC and PC/MLG nanocomposites varies linearly with temperature below their glass transition. Upon the addition of MLGs, the overall thermal stability of PC/MLG nanocomposites increases with MLG loadings. A maximum increase about 29.23°C in T onset of thermal decomposition is observed in PC/MLG nanocomposite having 3 wt% of MLG loading. The activation energy (Ea) of thermal decomposition is also calculated by kinetic analysis of thermal decomposition of the PC/MLG nanocomposites using Horowitz–Metzger and Broido's methods. [ABSTRACT FROM AUTHOR]

Polyhedral oligomeric silsesquioxane POSS nanoparticles can be applied as reinforcing additives modifying various properties of biodegradable polymers. The effects of aminopropylisobutyl POSS (amine-POSS), trisilanolisooctyl-POSS (HO-POSS) and glycidyl-POSS (Gly-POSS) on the viscoelastic, thermal properties and crystallization of biodegradable poly(ε-caprolactone) PCL were studied. The analysis of the viscoelastic properties at ambient temperature indicated that aminopropylisobutyl POSS (amine-POSS) and glycidyl-POSS (Gly-POSS) enhanced the dynamic mechanical properties of PCL. The increase in the storage shear modulus G′ and loss modulus G″ was observed. The plasticizing effect of trisilanolisooctyl POSS (HO-POSS) due to the presence of long isoctyl groups was confirmed. As a result, the crystallization of PCL was facilitated and the degree of crystallinity of χc increased up to 50.9%. The damping properties and the values of tan δ for PCL/HO-POSS composition increased from 0.052 to 0.069. The TGA results point out the worsening of the PCL thermal stability, with lower values of T0.5%, T1% and T3%. Both HO-POSS and Gly-POSS facilitated the relaxation of molten PCL. The presence of Gly-POSS influenced the changes that occurred in the viscoelastic properties of the molten PCL due to the thermo-mechanical degradation of the material; a positive impact was observed. [ABSTRACT FROM AUTHOR]

Sodium niobate (NaNbO3) powders and nanowires were synthesized and subsequently used for preparing composites with polyvinylidene-fluoride (PVDF) using the cold sintering technique in the weight ratio of 80:20 (ceramic:polymer). Phase purity of ceramic powders and nanowires was confirmed by X-ray diffraction analysis. Different phases of PVDF formed under various process parameters were also identified. Thermo-gravimetric analysis was performed in order to check the thermal stability of the composites. SEM was used to study the surface morphology of these samples, and energy dispersive x-ray analysis was also carried out in order to view the distribution of polymers in the composites. Furthermore, the formation of the ceramic matrix in the composites was verified and distribution of polymers in the ceramic matrix was examined by micro-computed tomographic analysis. Dielectric constant and loss tangent were measured and compared with the theoretically calculated values. Theoretical breakdown strength and energy density were calculated and were found to be as high as 1345 kV/cm and 6.1 J/cm3, respectively, at room temperature. Discharge efficiency of 64% was obtained for annealed nanocomposites. [ABSTRACT FROM AUTHOR]

Two types of polyethylenes, the crosslinked high‐density polyethylene (PEX) and the short‐chain branched medium‐density polyethylene (polyethylene of raised temperature resistance [PE‐RT]), are selected as matrices for graphene nanoplatelets (GNPs) nanocomposites preparation (PEX/GNPs, PE‐RT/GNPs). The melt‐mixing technique is used to synthesize the nanocomposites containing various loadings of GNPs. Differential scanning calorimetry (DSC) is employed to study the effect of the GNPs on the melting and crystallization behavior of the prepared materials. The thermal stability of the nanocomposites was evaluated by thermogravimetric analysis (TGA). Laser flash analysis (LFA) is used to estimate the thermal conductivity of both PEX and PE‐RT/GNPs nanocomposites. TGA measurements reveal that PEX nanocomposites present decreased thermal stability with increasing filler content. The DSC results show that the crystallinity of both matrices increases with increasing filler content. PEX/GNPs nanocomposites show more significant thermal conductivity augmentation compared to the corresponding PE‐RT nanocomposites. [ABSTRACT FROM AUTHOR]

Nanocomposites of polyvinylidene fluoride (PVDF) with dimensional (1D) cobalt oxide (Co3O4) and f-MWCNTs were prepared successfully by the solution casting method. The impact of 1D Co3O4 filler and 1D Co3O4/f-MWCNTs co-fillers on the structural, thermal, and electrical behavior of PVDF were studied. The crystal structural properties of pure PVDF and its nanocomposite films were studied by XRD, which revealed a significant enhancement of β-phase PVDF in the resulting nanocomposite films. The increase in β-phase was further revealed by the FTIR spectroscopic analysis of the samples. TG, DTA, and DSC analyses confirmed an increase in thermal stability of PVDF with the addition of nano-fillers as well as their increasing wt.%. From impedance spectroscopic studies, it was found that the DC conductivity of PVDF increases insignificantly initially (up to 0.1 wt.% of nano-fillers addition), but a significant improvement in DC conductivity was found at higher concentrations of the nano-fillers. Furthermore, it was observed that the DC conductivity decreases with frequency. The increase in DC conductivity corresponded to the strong interactions of nano-fillers with PVDF polymer chains. [ABSTRACT FROM AUTHOR]

This article addresses the effect of nanocrystalline cellulose (NCC) on the mechanical and thermal properties of polypropylene (PP). A new approach was adopted to produce mechanically improved and thermally stable PP-NCC nanocomposite. This approach involved producing optimized PP-NCC nanocomposite by adding NCC nanoparticles to PP matrix at different concentrations by means of injection molding process. The aim of this work was to find the optimum NCC concentration to enhance the mechanical and thermal properties of the PP matrix. The mechanical and thermal behavior of PP-NCC nanocomposite was studied by performing three-point bend, nanoindentation, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectroscopy tests. The results showed that the mechanical properties of strength, modulus, and hardness of the nanocomposites increased with the addition of NCC by 6.5%, 19%, and 150%, respectively. DSC results showed that the addition of NCC to PP does not affect the thermal stability (melting temperature). However, TGA showed that upon inclusion of NCC nanoparticles, the thermal stability of the samples improved compared to pure PP except for the 5% added NCC. This is attributed to the presence of NCC rod-like particles that dissipated heat by generating tortuous paths, as depicted in the SEM results and verified by FTIR results. [ABSTRACT FROM AUTHOR]

Nanocomposites composed of polypropylene (PP), organoclay, ethylene acrylic acid (EAA), and maleic anhydride-grafted polypropylene (PP- g -MA) were prepared using the melt mixing technique, and their thermal stability properties were investigated. PP- g -MA and EAA were used as compatibilizers in the nanocomposites. The effects of different concentrations of organoclay on the physical properties of nanocomposites were investigated. The kinetics of PP/organoclay nanocomposite degradation were investigated by thermogravimetric analysis, the activation energy of nanocomposite system was confirmed by the Kissinger method, and the performance of nanocomposites was investigated by differential scanning calorimetry, ARES rheometer, and transmission electron microscopy. The test results show that the addition of organoclay can improve the thermal stability of PP/organoclay nanocomposites, and the activation energy is slightly improved; rheological analysis shows that as the organoclay is gradually added to the composite system; the fluidity of PP and the processing properties are improved. In addition, the mechanical properties were measured, and it was found that an appropriate organoclay content can effectively improve the mechanical properties of nanocomposites. [ABSTRACT FROM AUTHOR]

In the research described here immiscible polymer blends based on amorphous poly(methyl methacrylate) (PMMA) and semi-crystalline polypropylene (PP) were produced via a melt-mixing method. The effects of the addition of graphene and clay nanoparticles on the compatibility and properties of the blends were investigated. Scanning electron microscopy results showed that the neat blends at all compositions were severely phase separated and a droplet-in-matrix morphology was attained. Introduction of graphene and clay caused the compatibility of the blends to be highly enhanced and, thus, a finer and more uniform morphology was obtained for the nanocomposites. Based on the morphology results, it was found that graphene had more affinity toward the PP phase and clay was more compatible with PMMA. This hypothesis was further proved via mechanical analysis and thermogravimetric analysis (TGA) results. The toughness of the neat blends was increased upon increasing the PP content; however, it was reduced for all the nanocomposites relative to the blend of the same polymer composition. The thermal stability of the blend at a composition of 70/30 PMMA/PP was improved via addition of clay and graphene. The first stage of degradation (PMMA) was shifted to higher temperatures once clay was added to the system while the second stage of degradation (PP) was impeded upon addition of graphene. [ABSTRACT FROM AUTHOR]

This study compares the reinforcing effects of graphene nanoplatelets (GNP), graphene oxide (GO), and halloysite nanotubes (HNTs) in polypropylene (PP) based nanocomposites with PP‐g‐maleic anhydride (MAPP) as compatibilizer. PP/GNP/MAPP, PP/GO/MAPP, and PP/HNTs/MAPP nanocomposites were fabricated at nanofillers contents 1, 2, 3, 4 parts per hundred (phr) and MAPP at 4 phr, to PP matrix, using melt extrusion and injection molding techniques. Results show that at nanofillers optimum content, PP/GNP3/MAPP nanocomposite increased in tensile strength and modulus by 8% and 96%, respectively, compared to pure PP (p ˂ 0.05). PP/GNP3/MAPP nanocomposite also increased in tensile strength and modulus by 2% and 4% respectively, compared to PP/GO2/MAPP (p ˂ 0.05) and 2% and 15% compared to PP/HNTs2/MAPP (p ˂ 0.05) nanocomposites. For impact strength performance, PP/GNP2/MAPP nanocomposite increased in impact strength (notched) by 104% compared to pure PP (p ˂ 0.05). Also, PP/GNP2/MAPP nanocomposite increased in impact strength by 23% compared to PP/GO1/MAPP (p ˂ 0.05) and 13% compared to PP/HNTs1/MAPP (p ˂ 0.05), nanocomposites. In flexural properties, PP/GO4/MAPP nanocomposite increased in flexural strength and modulus by 24% and 28%, respectively, compared to pure PP (p ˂ 0.05). Also, PP/GO4/MAPP nanocomposite increased in flexural strength and modulus by 4% and 9%, respectively, compared to PP/GNP2/MAPP nanocomposite, and 9% and 21% respectively compared to PP/HNTs2/MAPP nanocomposite. PP/GNP2/MAPP nanocomposite increased in thermal stability by 12°C compared to pure PP; 29°C compared to PP/GO2/MAPP; and 15°C compared to PP/HNTs2/MAPP nanocomposites. Overall, PP/GNP/MAPP nanocomposite exhibited superior mechanical properties and thermal stability compared to PP/GO/MAPP and PP/HNTs/MAPP nanocomposites. PP/GO/MAPP was superior for bending properties while PP/HNTs/MAPP was best for ductility. [ABSTRACT FROM AUTHOR]

The impact of bacterial diseases and the development of effective antimicrobial agents have drawn much consideration as a main healthcare challenge. The effects of montmorillonite/silver nanocomposites (MMT/Ag NCs) as a nanofiller on mechanical and thermal properties of linear low-density polyethylene/ethylene–vinyl acetate copolymers blend (LLDPE/EVA) had been investigated. The antimicrobial potential of the synthesized samples had been studied. The developed LLDPE/EVA/MMT/Ag nanocomposites films (NCFs) had been characterized by UV–Vis. spectroscopy, FTIR and XRD analysis. The mechanical, and thermal properties of LLDPE/EVA/MMT/Ag NCFs had been investigated. The results showed that incorporating the MMT/Ag NCs at lower phr (part per hundred resins) content resulted in both improvement in the mechanical properties and the thermal stability. The antimicrobial results demonstrated that LLDPE/EVA blend with 5 phr MMT/Ag NCs possesses the most powerful impact on the tested microbes. The SEM analysis of the treated cells showed, noticeable morphological abnormalities (the complete lysis of the outer surface followed by deformations of cells). Accordingly, the synthesized nanocomposites open the area of interest for possible application in a broad range of purposes like environmental and biomedical applications. [ABSTRACT FROM AUTHOR]

Enhancing the mechanical properties and thermal stability of phthalonitrile polymers by hybrid modification holds significant importance in broadening their thermal-structural applications within high-temperature environments. Herein, fumed silica nanoparticles were considered as modifiers for a class of phenolic-type phthalonitrile resin, i.e., PN75, and their effects on mechanical properties and thermal stability were explored. First, contact angle tests (CA) were employed to show that the PN75 melt had good wettability on hydrophilic fumed silica (FS) and poor wettability on hydrophobic fumed silica (RFS). FS had a relatively satisfactory dispersion within PN75, which was indicated by scanning electron microscope (SEM), followed by FS/PN75 nanocomposites were prepared by melt blending under vacuum, with maximum FS addition 3 wt% of PN75. Second, the flexural strength and modulus of nanocomposites were increased by 23.5% and 11.9%. Finally, thermal stability of the FS/PN75 was promoted from 21.6% to 25.6% in char residue at 800 °C in the air atmosphere by the thermogravimetric analysis (TGA), which was contributed by the high heat-resistance and the shielding effect of FS. This work would inspire in-depth studies on modification and design of phthalonitrile-based hybrid composites for extreme thermal environment. [Display omitted] • Hydrophilic fumed silica exhibited well wettability with phenolic-type phthalonitrile resin. • Vacuum melt blending was proven as an efficient process achieving well dispersion of fumed silica nanoparticles. • Addition of fumed silica into phthalonitrile polymers improved the flexural strength and the char residue. [ABSTRACT FROM AUTHOR]

The aim of this study was to produce new nanocomposites with antimicrobial, antioxidant and anticancer properties that can be used in biomedical research based on carboxymethyl cellulose (NaCMC) biopolymer. First, poly(2-oxo-2-(pentafluorophenoxy)ethyl-2-methylprop-2-enoate) (PPFMA) was synthesized and characterized by FTIR and NMR techniques. It was then blended with NaCMC by in situ/hydrothermal method to produce a semi-synthetic functional material. Changes in the FTIR data of the blend and the single Tg value from DSC confirmed the compatibility of the blend. To enhance the thermal and biological properties of the NaCMC-PPFMA blend, biosynthesized Ag-ZnONPs were hydrothermally incorporated into the blend at different weight ratios. The prepared materials were characterized by SEM, EDX, TEM, XRD and FTIR. The thermal stability of the materials was determined by thermogravimetric analysis (TGA), and glass transition temperatures (Tg) was determined by differential scanning calorimeter (DSC). The oxidant, antioxidant, antimicrobial, and cytotoxic properties of PPFMA, Ag-ZnONPs, PPFMA-NaCMC blend, and nanocomposites were investigated in detail. The total oxidant state (TOS) value of the NaCMC-PPFMA blend, which was 0.72 μmol equivalent H 2 O 2 /L, increased to 7.2–10.4 μmol equivalent H 2 O 2 /L with the addition of Ag-ZnONPs. Ag-ZnONPs decreased total antioxidant state (TAS) levels of the nanocomposites while increasing their oxidant activity. Therefore, an increase in the antimicrobial activity of the nanocomposites was observed. Adding Ag-ZnONPs to the NaCMC-PPFMA blend increased the thermal stability by 22 °C and the Tg value by 9 °C. Finally, the potential of Ag-ZnONPs containing nanocomposites in wound healing therapies was examined. The findings suggest that nanocomposites prepared by incorporating Ag-ZnONPs into the semi-synthetic NaCMC-PPFMA blend can be a source of bio-safe raw materials and can be used as potential wound healers. [ABSTRACT FROM AUTHOR]

In this review, we survey the state of the art on polymeric foams incorporating nano-scale fillers. Particular focus of the review is on foams from polyolefinic nanocomposite formulations incorporating a wide variety of fillers. The nano-scale additives can influence the foam structure and properties in two ways: Firstly, they can act as composite reinforcement to enhance the mechanical properties and functionality of the matrix polymer; and secondly, they can act as foaming-processing aids through modification of the rheological, thermal and crystallization properties of the matrix as well as serving as heterogeneous nucleation sites. Through a combination of these influences, and using advanced processing techniques it is possible to achieve nanocomposite foams that have higher cell density, and more uniform cell size or controlled cell-size distribution. Such controlled foam morphologies, in turn, can yield better specific mechanical properties resulting in more effective light-weighting solutions. Further, the nano-scale additives can impart additional desired functionality resulting in multi-functional foams. In this article, we provide an overview of the mechanical, thermal and a few other relevant functional properties – such as piezoelectric sensitivity, acoustics, and filtration efficiency – of foams prepared using nanocomposite formulations, along with the processing considerations for achieving high quality foams using such materials. [ABSTRACT FROM AUTHOR]

An ethoxylated polyethylene wax (E‐OPEW) was synthesized by PEGylation reaction between methoxy polyethylene glycol and oxidized PE wax. Clay nanoparticles were modified with different ratios of E‐OPEW and then compounded with PP by the melt mixing process. E‐OPEW and PP showed excellent compatibility, but at high percentages of wax (15%), incompatibility occurred between the two phases. In addition, the presence of modified clays in the PP matrix decreased the crystallinity percentage, though it did not change the melting temperature significantly. The results showed that functionalized wax is able to penetrate between clay platelets and increase the distance between them and improve their dispersion in the polymer matrix. Furthermore, it was observed that the distance between clay platelets increased by increasing E‐OPEW content. In addition, this result led to a significant improvement in the barrier properties of clay platelets and the thermal stability of the modified nanocomposite compared to other cases. Despite the improved dispersion of nanoparticles, the mechanical strength of nanocomposites decreased at a high percentage of E‐OPEW. [ABSTRACT FROM AUTHOR]

This research was targeted to investigate the effect of oxygen plasma treated graphene nanosheets (tGNSs) on the thermal stability of benzoxazine resin and to have a further and deeper mechanistic understanding of thermal decomposition kinetics of such nanocomposites in 0.5, 1 and 3 wt% of tGNS. The samples were prepared as reported in our previous study. The quality of dispersion of tGNSs within benzoxazine was investigated by X-Ray diffraction (XRD) and scanning electron microscopy (SEM) technique. Also, to ensure the complete curing of samples the differential scanning calorimetry (DSC) analysis was performed. Using thermogravimetric analysis (TGA), it was found that the addition of tGNS improved the char yield and thermal stability parameter of benzoxazine nanocomposites and this improvement was more prominent at 1% and higher amount of nanoparticles. Moreover, the first stage of thermal degradation kinetic of benzoxazine was disappeared above 1 wt% of tGNS. The samples were kinetically analyzed through Kissinger, Flynn-Wall-Ozawa and Friedman and Coats-Redfern method. It was revealed that the overall activation energy was enhanced from 168 to 224 kJ mol−1 and 275 to 420 kJ mol−1 for the second and third stage of degradation using 1 and 3 wt% of tGNS. [ABSTRACT FROM AUTHOR]

Poly(methyl methacrylate)/silica nanocomposites membranes were prepared by simple solution mixing method using three different solvents (acetone, acetonitrile and chloroform). The structure and thermal properties of these nanocomposites were investigated by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and environmental scanning electron microscope (ESEM). The infrared spectra confirm that the strongest H-bond interaction between the PMMA and silica was found when using chloroform solvent. In the case of thermal properties, the DSC and TGA analyses show significant improvement in thermal stability and glass transition temperature (Tg). Furthermore, the ESEM micrographs prove the structure stability of these synthesized nanocomposites. The results demonstrate that the solvent that lead to form the strongest H-bond interaction between the PMMA carbonyl groups and silica silanol groups (as chloroform solvent) will be more efficient in the synthesis of PMMA/SiO2 nanocomposites. [ABSTRACT FROM AUTHOR]

Bio-degradable and eco-friendly plasticized starch/reduced graphene oxide (PS/rGO) nanocomposites were made by a simple aqueous casting method. The effect of the rGO nanofiller on the structural, surface-morphological, mechanical, thermal, and electrochemical properties of the nanocomposite was studied. rGO enhances the thermal stability and significantly improves the mechanical strength of the polymer nanocomposite. The PS/rGO nanocomposite exhibits improved electrochemical performance and a specific capacitance as high as 42.25 F/g at a current density of 0.1 mA/cm2, which is about 20 times higher than that of PS (2.51 F/g). These improved thermal, mechanical, and electrochemical properties of the PS/rGO may be attributed to the good interfacial interaction and preferential orientation of rGO sheets in the nanocomposites. The PS/rGO nanocomposites with improved thermal and mechanical properties together with enhanced electrochemical performance produced from an easy and low-cost process will provide a sustainable way for the fabrication of eco-friendly energy storage devices. [ABSTRACT FROM AUTHOR]

This article focuses on the investigations on mechanical and thermal properties of the epoxy/poly(styrene‐co‐acrylonitrile) (SAN)/cloisite 20A nanocomposites. The analysis is performed in two particular compositions of epoxy/SAN blends to study the effect of nanoclay addition. The compositions of blends, epoxy/5 phr SAN and epoxy/15 phr SAN, are selected based on the difference in phase separation mechanism and microstructure. An increment in tensile strength is observed for epoxy/5 phr SAN/1 wt% cloisite 20A nanocomposite. Young's modulus is increased in epoxy/15 phr SAN/cloisite 20A nanocomposites. A surge in the toughness and impact properties is observed for the nanocomposites. Beneficial increment in activation energy for thermal degradation is observed for epoxy/SAN blends and epoxy/SAN/cloisite 20A nanocomposites. The nanocomposites are suitable for high temperature applications without much compromise in the mechanical properties. [ABSTRACT FROM AUTHOR]

Stereocomplexable polylactide (sc-PLA) with improved thermomechanical performance had been prepared by melt compounding of poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and nanosilica. The silica nanoparticles dispersed evenly in the sc-PLA matrix and there were no air bubbles because of good compatibility between nanosilica and sc-PLA. The aggregates size of nanosilica increased with increasing nanosilica content. The introduction of nanosilica facilitated the formation of stereocomplex, which was manifested as the degree of crystallinity of sc-PLA increased from 17.0 to 24.3% as the nanosilica content increased from 0 to 10 wt%. Thermal stability of sc-PLA was greatly improved by adding nanosilica, and the onset of decomposition temperature of sc-PLA/silica nanocomposites was ~33 °C higher than that of neat sc-PLA. Superior storage modulus was found for sc-PLA/silica nanocomposites compared to neat sc-PLA. The tensile strength and modulus of sc-PLA nanocomposites were greatly improved by the addition of nanosilica, but the elongation at break decreased. [ABSTRACT FROM AUTHOR]

The aims of this study were to improve the low thermal stability of poly(vinylacetate) (PVAc) polymer by forming its nanocomposite products according to solvent casting method with multi-walled carbon nanotube (MWCNT) and/or modified (functionalized) MWCNTs, and to perform thermal kinetics analysis of the thermal properties improved nanocomposites. Functionalization of p-MWCNTs (purified MWCNT) was carried out by hydroxylation, carboxylation and silylation reactions. The effects of the surface modification, the type of functional groups and the filler ratio to the thermal properties of the nanocomposites were investigated. The synthesized nanocomposites were characterized by Fourier transform infrared spectrum, differential thermal analysis-thermogravimetry (DTA/TG) and scanning electron microscope (SEM). It was found that; (i) the p-MWCNT was modified, (ii) the carbon nanotubes were dispersed in the tube structure in the PVAc matrix, (iii) the thermal stabilities, degradation temperatures (Tmax1 and Tmax2) and Tx values of PVAc/p-MWCNT-COOH (1 wt%) and PVAc/p-MWCNT-O-APTS (0.5 wt%; APTS: 3-aminopropyltriethoxysilane) nanocomposites were increased, (iv) the experimental results were quite compatible with the Flynn-Wall-Ozawa method and (v) the activation energy of the second step was higher. [ABSTRACT FROM AUTHOR]

Magnetic Fe2O3 nanopowder was synthesized and characterized by various analytical techniques. The PVA/Fe2O3 nanocomposites were prepared by solution casting method to investigate the effect of nanofillers on their physicochemical properties. The analytical tools such as FTIR, UV–visible spectra and XRD were used to analyze the structure of Fe2O3 nanopowder and PVA/Fe2O3 nanocomposites. The uniform distribution of the Fe2O3 nanofillers on the PVA matrix was inspected using SEM. The particle size of the crystalline Fe2O3 nanofillers was observed to be less than 30 nm from the TEM micrographs. The optical characteristics of the prepared samples were investigated by analyzing their UV–visible spectra. The bandgap of PVA nanocomposites was lower than for pure PVA due to the dispersed Fe2O3 nanofillers in the PVA matrix. The thermal properties of pristine PVA and PVA/Fe2O3 nanocomposites were investigated by TGA. The PVA/Fe2O3 nanocomposite systems exhibited the improved thermal stability. The thermal degradation mechanism of PVA/Fe2O3 nanocomposite system was inspected in depth at five different heating rates under non-isothermal conditions. The electrical and mechanical properties of PVA were enhanced remarkably while increasing the % weight loading of nanopowder. [ABSTRACT FROM AUTHOR]

The assembling of two carbonaceous nanomaterials to fabricate 3D hierarchical graphene-carbon nanotube hybrid is the superlative strategy to synergistically impart electrical and mechanical properties to polymers. In the present study, we have evaluated the effects of nanoscale hybridization of graphene oxide (GO) and multi-wall carbon nanotube (MWCNT) on the electrical, mechanical and thermal properties of polyetherimide (PEI) nanocomposites reinforced by GO-MWCNT hybrid. Synthesis of GO-MWCNT hybrid was confirmed by various spectroscopic measurements. The inclusion of GO-MWCNT hybrid to PEI endows optimum dispersion and better interfacial interactions between GO-MWCNTs and PEI matrix and thus remarkably improved the conductivity, tensile properties and thermal stability of PEI. When the mass ratio of GO to MWCNT is 1:1 and the total filler loading is only 2 wt%, the DC conductivity of the nanocomposite films enhanced by 6 orders of magnitude, the tensile strength increased by fourfold and the Young's modulus increased by sixfold compared to those of pure PEI. The reinforcement efficiency of the GO-MWCNT (1:1) hybrid in terms of the modulus of the nanocomposite was predicted using modified Halpin–Tsai modelling and compared with the experiment results. The present PEI nanocomposite materials could significantly fulfil the demands raised by the aerospace community. [ABSTRACT FROM AUTHOR]

This article describes micro‐ and nanostructural, mechanical, and thermal properties of nanocomposites based on polyvinyl chloride (PVC) and graphene nanoplatelets (GNP). The primary objective of this study was to extend restricted application area of PVC due to its low thermal stability and limited mechanical properties. GNP‐filled PVC nanocomposites were prepared (0, 0.1, 0.3, 0.5, and 1.0 wt%) by colloidal blending method and characterized in detail. The highest value of the tensile strength 13.73 MPa (an increase of 58%) and the highest value of microhardness 83.42 MPa (an increase of 82%) were obtained with GNP loading content of 0.5 wt% compared neat PVC. The mechanical properties started to decrease at loading higher than 0.5 wt%; however, the thermal properties continued to increase. The differential scanning calorimetry and Fourier transform infrared analysis results of this nanocomposite confirmed that the increase in glass transition temperature from 34.99°C to 44.36°C and the decrease in the height of functional groups peaks proved to prevented segmental relaxation and intermolecular vibrations of PVC, respectively. Thermogravimetric analysis results were showed that the percentage of carbonaceous residue increased to 15.77% by increasing the GNP content from 0.1 to 0.5 wt%. As a result, the best GNP loading was at 0.5 wt% for PVC/GNP nanocomposites where mechanical and thermal properties of PVC/GNP were both enhanced. [ABSTRACT FROM AUTHOR]

In this study, the synthesis, characterization, and thermal properties of poly(2-(4-methoxyphenyl amino)-2-oxoethyl methacrylate) (MPAEMA) polymer/clay based nanocomposites were investigated by in situ polymerization. At the characterizations of nanomaterials FTIR, XRD, SEM, and TGA techniques were used. It was determined from XRD and SEM measurements that the morphology of nanocomposites was exfoliated when the clay content in the polymer matrix was kept at 3% and 5%. From thermal analysis, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials. [ABSTRACT FROM AUTHOR]

Polymer‐based nanocomposites with good dielectric behavior have engrossed research devotion because of their distinctive benefits in electronic applications. An in situ synthetic process for the polybenzimidazole functionalized graphene oxide (GBI) and its nanocomposite with poly(vinylidene fluoride) (PVDF) is described. GBI shows good dispersion in the bulk PVDF matrix implying a strong interaction of polybenzimidazole with PVDF as evident from morphological and FTIR studies. A gradual increment of GBI in PVDF increases its piezoelectric β‐polymorph formation with a maximum of 73% for 10 wt % GBI in PVDF (GBF10) which also exhibits highest thermal stability. An exhaustive study of frequency dependent electrical properties of GBF10 indicates significantly higher dielectric constant (61), low dielectric loss (0.42), and low AC conductivity value of 1.17 × 10−10 S/cm at 100 Hz which are the key properties of a suitable capacitor. GBF10 also shows hydrophobic behavior (water uptake 2.89%) and low swelling ratio (1.143), providing an opportunity to use the composite film in fuel cell application. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 189–201 Covalently functionalized graphene oxide with polybenzimidazole (GBI) shows homogenous dispersion in poly(vinylidene fluoride)(PVDF), and the composite exhibits 73% piezoelectric β‐polymorph formation for 10 wt % GBI in PVDF (GBF10). It shows significantly higher dielectric constant (61), low dielectric loss (0.42), and a low AC conductivity of 1.17 × 10−10 S/cm at 100 Hz appropriate for a capacitor. It also shows hydrophobic behavior (water uptake 2.89%) and low swelling ratio (1.143), providing an opportunity to use the composite film in fuel cell applications. [ABSTRACT FROM AUTHOR]

In this study, poly(2-(3,5-dichloroanilino)-2-oxoethyl 2-methylprop-2-enoate) (PDCOEMA), a new synthetic polymer based on methacrylate, was synthesized and characterized. The blend of PDCOEMA with chitosan (CS) was prepared by the hydrothermal method and the DSC technique confirmed its formation. It was observed that PDCOEMA increased the thermal stability and glass transition temperature (Tg) of CS. The Tg value of the PDCOEMA-CS blend was increased at about 7 °C with the highest ZnO NPs contribution rate. PDCOEMA-CS/ZnO nanocomposites were prepared by adding ZnO NPs produced by biosynthesis at different weight ratios to the PDCOEMA-CS blend by hydrothermal method. When the thermal stability of nanocomposites determined by TGA was examined, it was observed that it increased significantly compared to CS. While the initial decomposition temperature of CS was 270 °C, this value increased to 293 °C after blending with DCOEMA, and to 317 °C with the addition of 7 % ZnO NPs. Antimicrobial, anticancer, cytotoxic, antioxidant, and wound healing properties of PDCOEMA, CS, PDCOEMA-CS blend, and nanocomposites were determined. According to the obtained results, it was observed that nanocomposites containing 5 % and 7 % ZnO NPs showed good anticancer activity against A549 cells at a dose of 10 μg/mL. The results show that the produced nanocomposites can contribute to developing CS-based materials. [ABSTRACT FROM AUTHOR]

To obtain a safe and biodegradable material for food packaging, this study developed a facile and green process of anchoring nisin onto oxidized cellulose through a simple Schiff base reaction for long-term antimicrobial active food packaging. To the best of our knowledge, this is the first report of such a packaging. The grafting reaction between the amino groups of nisin and the aldehyde groups of oxidized cellulose films was successfully established to obtained a nisin anchored cellulose films (NC) membrane; the structure was characterized with Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The NCs membrane had an outstanding transparent property of above 90% transmittance through 300 nm to 800 nm; while, the barrier properties against oxygen remain excellent. The thermal stability of the NCs membrane remained excellent and enabled an easier degradation than the original cellulose membrane. The NCs membrane displayed good antimicrobial activity against Alicyclobacillus acidoterrestris DSM 3922T in a long-term way, thus demonstrating good potential as food packaging material. The obtained results are promising and confirm the development of NCs membranes as green materials for food packaging. [ABSTRACT FROM AUTHOR]

Industrially relevant nanopowder was synthesised by microwave hydrothermal synthesis to obtain well-controlled composition (ZrO2–AlO(OH) system) which was found to determine a number of physical and thermal characteristics. This study reports variation of particle size, density, specific surface area (SSABET), as well as thermal behaviour of nanopowder mixtures of ZrO2–AlO(OH) in the whole range of compositions. It was found that the onset temperature (Ton) of physically and chemically bounded water desorption depends on the Al3+/or AlO(OH) content. The lower content of Al3+ in the ZrO2–AlO(OH) system, the higher Ton of physically bound water desorption. There are three distinct temperature regions for water decomposition for nanomaterials investigated in air (at approximately 50, 250 and 450 °C). These temperature ranges depend on particle size and chemical composition of ZrO2–AlO(OH) nanopowders. Materials were divided into three groups characterised by different properties: (1) ZrO2 with 2–12% of Al3+, where particle sizes are from 4 to 8 nm, (2) ZrO2 with 30–67% of AlO(OH), where particle sizes are from 10 to 13 nm, and (3) ZrO2 with 80–99% of AlO(OH), where particle sizes are from 13 to 23 nm. AlO(OH) content determines thermal and physico-chemical properties of synthesised ZrO2–AlO(OH) nanopowders. [ABSTRACT FROM AUTHOR]

To improve the flame retardancy of epoxy resin (EP), copper phenylphosphate (CuPP) nanoplates were designed and prepared by mixed solvothermal technique, which were incorporated into EP matrix and fabricated EP/CuPP nanocomposites. The results showed that the product was Cu(HO 3 PC 6 H 5 ) 2 with appropriate thermal stability, and EP/CuPP nanocomposites displayed excellent catalytic charring performance compared with pure EP. The combustion results indicated that pure EP had no rating and its LOI value was only 23.0%. With incorporation of 4 wt% CuPP, EP/4 wt% CuPP nanocomposites passed the UL-94 V1 rating and the LOI value reached 38.2%. The improved flame retardancy of EP/CuPP nanocomposites was proved by cone calorimeter test, and the peak heat release rate, total smoke production, peak CO production value of EP/4 wt% CuPP nanocomposites dramatically decreased by 51.7%, 52.4% and 47.3%, which were attributed to the formation of hard and condensed residues layers on the surface of EP nanocomposites. Additionally, the incorporation of CuPP improved the dynamic mechanical performance of EP nanocomposites, which may be due to the reinforcement effect of CuPP with rigid structure. [ABSTRACT FROM AUTHOR]

The aim of this work was to prepare and characterize the series of segmented polyurethane nanocomposites (PUNC) modified with poly(dimethylsiloxane) and based on montmorillonite (Mt) as a nano-filler. α , ω -Dihydroxy-poly(propylene oxide)- b -poly(dimethylsiloxane)- b -poly(propylene oxide) macrodiol was used as the soft segment component, while 4,4′-diphenylmethane diisocyanate (MDI) and 1,4-butanediol (BD) were selected as the hard segment components. PUNC were synthesized with different ratio of hard/soft segments. PUNC were morphologically, structurally, thermally, mechanically and surface characterized by XRD, TEM, FTIR, AFM, TGA, DMTA, tensile test, XPS, contact angle, surface free energy (SFE) and water absorption measurements. Added Mt (1 wt%) was completely delaminated and well dispersed in the form of mixed exfoliated/intercalated layers in the polymer matrix, and that PUNC have more pronounced microphase separated morphology, higher thermal stability, superior mechanical features, enhanced surface properties, as well as outstanding hydrophobicity. Due to the improved features, developed polymers can be considered as candidates for materials with specific biomedical applications or as waterproof coatings. [ABSTRACT FROM AUTHOR]

ABSTRACT In present research, the effect of ammonium polyphosphate (APP) content on flame retardancy, thermal stability, and mechanical properties of unsaturated polyester resin/unsaturated phenolic resin/montmorillonite (MMT) nanocomposites were studied. Nanocomposites were prepared via in situ mold casting technique. Flame retardancy of the nanocomposite was investigated through the UL 94 vertical burning test and limiting oxygen index (LOI) analysis. Thermogravimetric analysis (TGA) was conducted to measure thermal properties, whereas flexural and impact tests were carried out to determine mechanical properties of nanocomposites. Nanocomposites with 30 phr APP achieved the flammability rating of V-1 and LOI of 29.2%. TGA results showed that nanocomposites with 30 phr APP had the highest thermal stability. Nanocomposite prepared with 3 phr MMT had the highest flexural strength, flexural modulus, and impact strength. Thus the best balance between flame retardancy, thermal stability, and mechanical properties was achieved with MMT and APP content of 3 and 30 phr, respectively. [ABSTRACT FROM AUTHOR]

• FT-IR confirms the interactions and complexation between PVP/PEO polymer blend doped with ZnO/TiO2 NP s. • XRD depicts that the amorphousity is increased after adding ZnO/TiO2 NP s. • Optical energy gap is decreased with increasing ZnO/TiO2 NP s concentrations. • TGA indicate that the thermal stability of the samples is increased. • By adding ZnO/TiO2 NP s the electrical conductivity is tremendously enhanced and the activation energy decrease. Polyvinyl pyrrolidone (PVP) and polyethylene oxide (PEO) hybrid nanocomposites with varying zinc oxide (ZnO) and titanium dioxide (TiO 2) concentrations were created using the solution casting process. The influence of ZnO/TiO 2 nanoparticles on the optical, thermal, and electrical properties of the pure PVP/PEO composite was investigated and discussed. The results of the XRD analysis show that as ZnO/TiO 2 NPs concentrations increases, the crystallinity of the nanocomposite films decreases. The interactions between the ZnO/TiO 2 nanoparticles and the PVP/PEO polymeric chain is shown by FT-IR spectra. Peak positions and intensity variations in the FT-IR absorption spectra are observed when the concentration increases from 0.5 to 2 wt.% of ZnO/TiO 2 NPs. The optical parameters including energy gap (E g), refractive index (n), and Urbach energy (E u) for PVP/PEO/ZnO/TiO 2 nanohybrid samples were calculated using UV/Vis analytical spectroscopy. The energy gap narrows when ZnO/TiO 2 nanohybrid concentration rises, as shown by the optical absorption spectra. The allowed indirect energy gap of the polymer matrix was reduced from 3.72 to 1.94 eV by the addition of 2 wt.% ZnO/TiO 2 NPs. The TGA curve shows that the ZnO/TiO 2 nanohybrid enhanced the thermal stability of the samples. As the concentration of metal oxides increased, the activation energy (E a) decreased. AC conductivity showed that the PVP/PEO -(2 wt.%) ZnO/TiO 2 NPs nanocomposites have higher electrical conductivity than PVP/PEO. For samples of -(2 wt.%) ZnO/TiO 2 , the σ d c of nanocomposites reached 4.64×10−5Scm−1. Exponential factor (S) results show that in nanocomposite samples with non-Debye relaxation processes, the correlated barrier hopping mechanism (CBH) is dominant. High values of ε' at low-frequency in the dielectric characteristics demonstrated space charge polarization, whereas higher values of ε" in the composite samples could be associated with an increase in energy loss. These results illustrate the appropriateness of these nanocomposites for variety of uses, including flexible capacitors, battery separators, and energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, a series of poly(ϵ-caprolactone) (PCL)/clay bionanocomposites were prepared viain situring opening polymerization (ROP) of ϵ-caprolactone catalyzed by titanium butoxide. The natural Moroccan clay beidellite (BDT), used as nanocharge, was organomodified with cetyltrimethylammonium bromide, CTA, to obtain the organically modified 3CTA-BDT (3 = CTA/BDT equivalent feed ratio). Characteristics of the final nanocomposites are investigated by FTIR, SEC, XRD, SEM, TGA, DSC, optical tensiometry, thermal conductivity and water vapor sorption analysis. The intercalated/exfoliated morphologies, revealed by XRD and SEM analyses, confirm uniform dispersion of the nanoclay within the PCL matrix. Thermal stability of all the nanocomposites is improved by the addition of 3CTA-BDT clay compared to pure PCL polymer. The DSC data show that the addition of 3CTA-BDT particles promotes an increase in the disorder of the crystalline phase, which reduces the crystallinity degree. The hydrophobicity of Polymer/clay compatibility was analyzed by studying surface polarity degree of samples by contact angle measurements. Thermal conductivity and water vapor sorption was also discussed. The permeability (P), the sorption coefficient (S) and the diffusion coefficient (D), showed a significant decrease with increasing 3CTA-BDT loading. [ABSTRACT FROM PUBLISHER]

In this investigation, halloysite (Hal) nanotubes were surface modified with 3-aminopropyltriethoxysilane (APTES) to enhance the surface interaction of Hal nanotubes with polylactide or poly (lactic acid) (PLA) and to achieve good dispersion of Hal nanotubes across the PLA matrix. Unmodified and silane modified Hal nanotubes were characterized by Fourier transform infrared spectroscopy (FTIR), Nitrogen adsorption-desorption analysis, Thermogravimetric analysis (TGA) and Field emission scanning electron microscopy (FE-SEM) with Energy-dispersive x-ray spectroscopy (EDX) analysis. Nitrogen adsorption-desorption, FTIR and TGA analysis results were confirmed the successful modification of Hal nanotubes surface with APTES. The different wt% of unmodified and APTES modified Hal nanotubes reinforced PLA polymer composites were prepared by using a laboratory scale melt mixer. The resultant Hal-PLA nanocomposites were characterized for their morphology, thermal, mechanical and dynamic-mechanical properties. Tensile strength increased to 62.6 MPa with the addition of 4 wt% of APTES modified Hal-PLA nanocomposites which is 26.5% higher than pure PLA and 15% higher than unmodified (4 wt%) Hal-PLA nanocomposites. Impact strength of 4 wt% APTES modified Hal-PLA nanocomposites was 29.8 MPa, which is 20% higher than the unmodified Hal-PLA nanocomposites and 40% higher than pure PLA. Thermal stability also increased by 17 °C with the addition of 4 wt% of APTES modified Hal nanotubes and 10 °C for the unmodified Hal nanotubes onto PLA. Storage modulus increased > 10% with the addition of 4 wt% of APTES modified Hal nanotubes as compared to pure PLA and tan delta values were decreased for the modified Hal nanotubes due to an increase in the compatibilisation between filler and matrix phase. Based on these results, APTES is one of the best choices for the functionalisation of inorganic surface such as Hal nanotubes. The mechanical and thermal properties significantly improved with the addition of a small quantity (4 wt%) of APTES modified Hal nanotubes. [ABSTRACT FROM AUTHOR]

Several composites and nanocomposites based on a polymeric matrix and ceramic fillers are being pursued for use as multifunctional and innovative materials. Nevertheless, there is a series of challenges to be solved in this area such as the understanding of the role of interfaces and the synergy between matrix and fillers. In this work, vulcanized natural rubber nanocomposites were prepared with different concentrations of two kinds of ceramic nanoparticles, potassium strontium niobate (KSrNbO or KSN) and nickel-zinc ferrite (NiZnFeO or NZF), synthesized by a chemical method known as the modified polyol method. Morphological and thermal characterizations were carried out by AFM, TG/DTG, TG/FTIR and DSC. The thermal properties of nanocomposites were compared and discussed as functions of concentration, type and surface of nanoparticles. The results obtained suggest that the base concentration for both types of nanoparticles inside the polymer matrix volume greatly adds to the increase in thermal stability up to 11 % and the glass transition temperature up to 10 °C. A similar evolution for the glass transition temperature ( T ), thermal stability temperature ( T ) and dielectric permittivity ( ε′) was identified, suggesting that these phenomena are mainly dominated by the same mechanisms. These results point to the possibility for the thermal parameter modulation in magnetic and ferroelectric nanocomposites by means of a suitable control of concentration and properties of the KSN and NZF nanoparticles. [ABSTRACT FROM AUTHOR]

This article presents the fabrication and characterization of poly dimethylsiloxane/carbon nanofiber (CNF)-based nanocomposites. Although silica and carbon nanoparticles have been traditionally used to reinforce mechanical properties in PDMS matrix nanocomposites, this article focuses on understanding their impacts on electrical and thermal properties. By adjusting both the silica and CNF concentrations, 12 different nanocomposite formulations were studied, and the thermal and electrical properties of these materials were experimentally characterized. The developed nanocomposites were prepared using a solvent-assisted method providing uniform dispersion of the CNFs in the polymer matrix. Scanning electron microscopy was employed to determine the dispersion of the CNFs at different length scales. The thermal properties, such as thermal stability and thermal diffusivity, of the developed nanocomposites were studied using thermogravimetirc and laser flash techniques. Furthermore, the electrical volume conductivity of each type of nanocomposite was tested using the four-probe method to eliminate the effects of contact electrical resistance during measurement. Experimental results showed that both CNFs and silica were able to impact on the overall properties of the synthesized PDMS/CNF nanocomposites. The developed nanocomposites have the potential to be applied to the development of new load sensors in the future. [ABSTRACT FROM AUTHOR]

The purpose of the present article is to modify the surface of nano-titanium dioxide (TiO) and to investigate the reinforcing effect of both unmodified and surface-modified nano-titanium dioxide (TiO) on the mechanical properties and thermal stability of natural rubber (NR) nanocomposites. Surface of nano-TiO is modified by polyethylene glycol (PEG) and polypropylene glycol (PPG). The effective surface modification of nano-TiO is evaluated by Fourier transform infrared (FTIR) spectra and field emission scanning electron microscopy (FESEM). The result notifies that the final properties of NR nanocomposites are dramatically improved in the presence of surface-modified nano-TiO in comparison to unmodified nano-TiO. The excellent reinforcing capability of surface-modified nano-TiO is due to its better hydrophobicity and uniform dispersion within the NR matrix, as confirmed from morphological analysis. Furthermore, due to its small size PEG is better surface modifier for nano-TiO than PPG. [ABSTRACT FROM AUTHOR]

Poly(ε-caprolactone) (PCL) nanocomposites with hybrid clay-supported carbon nanotubes (Clay-CNT) in concentrations 0.5, 1.0 and 2.5 wt% were prepared by melt mixing. Mechanical, structural and thermal properties of the nanocomposites were studied. All nanocomposites exhibited similar stress-strain patterns to those of neat PCL but, with increasing nanofiller content yield point and Young’s Modulus values increased, despite the absence of chemical interactions between PCL and Clay-CNT. It was also found that the crystallinity of the nanocomposites is the same as for neat PCL, but the nanofiller acts as nucleating agent which promotes the crystallization and also allows it to occur at higher temperatures. Thermal stability is instead negatively influenced by the nanofiller, since Clay-CNT catalyzes the decomposition of PCL at lower temperature. The monomer ε-caprolactone is the main decomposition product resulting from intramolecular esterification while cis -elimination at ester bonds (β-hydrogen bond scission) is favored at higher temperatures. [ABSTRACT FROM AUTHOR]

Two routes of nanocomposite generation, viz., the masterbatch method and direct melt mixing, were compared in the current study in relation with the properties of the polyethylene-thermally reduced graphene nanocomposites compatibilized with functional polymers. Filler dispersion was observed to improve in the masterbatch method due to preferential interactions of compatibilizer with the filler, before melt mixing with the matrix polymer. This also translated into improved mechanical properties as more than two times increment in tensile modulus was observed in the composite HDPE/G/5 EAA/MB (41 %, masterbatch method) as compared to HDPE/G/5 EAA/MM (20 %, melt mixing method). In addition, different compatibilizers also influenced the properties to a different extent owing to their physical interactions with the filler; however, composites generated with masterbatch were always superior in extent of property enhancements. Increasing the compatibilizer content to 10 % also caused varying degrees of matrix plasticization. The storage modulus as well as the complex viscosity of the HDPE/G/5 EAA/MB composite was the highest as compared to HDPE/G/5 EMAZ/MB and HDPE/G/5 EVA-MA/MB composites. HDPE/G/5 EAA/MB and HDPE/G/5 EMAZ/MB composites did not show any decrease in degree of crystallinity as compared to pure polymer, whereas the corresponding composites generated with melt mixing exhibited slight decrease in the crystallinity. The composites were observed to have enhanced thermal stability as compared to HDPE. Five percent EAA-based composites exhibited even higher thermal stability than did HDPE/G composites due to improved filler dispersion. Composites generated with the masterbatch approach had also higher degree of phase mixing than the corresponding melt mixed composites. [ABSTRACT FROM AUTHOR]

Starch based wood nanocomposites (WSNC) were prepared successfully from starch and soft wood with multi-walled carbon nanotube (MWCNT) as nano reinforcing agent through a completely green path. The most important part of this scheme was the use of water as the solvent. In this technique, starch was grafted with methylmethacrylate (MMA) and MWCNT was functionalised with hydroxyl groups ( f -MWCNT). Dimethyloldihydroxyethyleneurea (DMDHEU) was used as a cross-linker to prepare the green material from methylmethacrylate grafted starch (MMA- g -starch), soft wood flour and functionalised MWCNT. The functionalization of MWCNT was confirmed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and Raman analysis. Different properties of the WSNC were investigated by varying the concentration of f -MWCNT. The prepared nanocomposites exhibited outstanding thermal stability, mechanical properties and water resistance capacity compared to untreated wood composites. The flammability of the wood composites decreased up to 30% with just addition of 0.50 phr f -MWCNT. [ABSTRACT FROM AUTHOR]