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For several decades, forming blend and composite of polyaniline (PANI) with insulating polymers has been a widely studied research area because of the potential applications of such blends, which have a unique combination of mechanical properties, the processability of conventional polymers and the electrical property of conducting polymers. The current review paper will emphasize PANI composites or blends with thermosetting polymer matrices. The enhanced electro-mechanical properties of the blends and composites depend on the uniform dispersion of the PANI particle in polymer matrix. Therefore, considerable studies have focused on improving the distribution of PANI particles within the thermoset matrices. In this review paper, all the parameters and conditions that influence the surface morphology and application of PANI thermoset blends and composites will be described systematically. Recent progress on PANI based thermoset system with multifunctional ternary composites research will be highlighted in this paper. Furthermore, encouraging applications of different PANI thermoset composites and blends are discussed, such as flame-retardant materials, lightning damage suppression, metal ion removal, anticorrosive coating, electromagnetic shielding, conductive adhesives, and sensing materials. [ABSTRACT FROM AUTHOR]

The development of bio-compatible materials for bone implants bone healing is one of the key research areas in biomaterials. In this paper, composites of polyether-ether-ketone (PEEK) (a bio-compatible polymer) and hydroxyapatite (HA) were synthesized using thermal process, The qualities of the composites were analyzed with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) for characterizing the nature of stress and bonding. The morphological study of the PEEK-HA composites were studied through Scanning electron microscopy. The compressive nature of the composites as well as raw materials was observed based on XRD data with internal lattice-strain analysis. The temperature-modulated differential scanning calorimetry (TM-DSC) and conventional differential scanning calorimetry (DSC) were performed for analyzing the crystallization process. The TM-DSC showed that both reversing and non-reversing processes were active during the crystallization between 160 °C–330 °C. However, a higher residual time of PEEK at elevated temperatures tends to facilitate polymer degradation and spread the crystallization process over a broader temperature range. Addition of HA particles provided heterogeneous nucleation sites for crystallization but also reduced the mobility of polymer chains. The combination of enhanced nucleation rate, reduced chain mobility and polymer degradation processes together lead to a wide range of crystallinity in PEEK-HA composites. [ABSTRACT FROM AUTHOR]

In this paper, electrical and dielectric properties of multiwall carbon nanotubes (MWCNTs)/insulating polyaniline (PANI) composites were studied. A mixture of MWCNTs and insulating polyaniline was dispersed in an ethanol solution by ultrasonic process, subsequently dried, and was hot-pressed at 200 °C under 30 MPa. Electrical and dielectric properties of the composites were measured. The experimental results show that the dc conductivities of the composites exhibit a typical percolation behavior with a low percolation threshold of 5.85 wt.% MWCNTs content. The dielectric constant of the composites increases remarkably with the increasing MWCNTs concentration, when the MWCNTs concentration was close to percolation threshold. This may be attributed to the critical behavior of the dielectric constant near the percolation threshold as well as to the polarization effects between the clusters inside the composites. [ABSTRACT FROM AUTHOR]

In recent years, there has been a significant demand for shape memory materials due to their smart characteristics. NiMnGa has special interest because of its magnetic shape memory features which can be used in actuators, sensors, dampers, and energy harvesting. The production of NiMnGa has a substantial cost resulting in usage of a shape memory polymer composite with the alloy which brings advantages such as size, and shape structure. For this purpose, a new multifunctional smart material was studied by combining Poly lactic acid (PLA)/Poly ethylene glycol (PEG) blend obtained with Ni49.5Mn29.5Ga21 (in % atomic). Different ratios of the alloy were doped into the blend to investigate the effect of the alloy on the characteristic features of the composite. Physicochemical properties of NiMnGa enriched composites were analyzed by attenuated total reflectance infrared spectroscopy (ATR-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM). From DSC analysis it is concluded that the magnetically enhanced PLA/PEG films with the alloy had two important phase transformations. Although NiMnGa shape memory alloy did not affect the initial decomposition temperature (Ti) of the PLA/PEG blend much, the residue ratio increased with increasing alloy content. The characteristic XRD signal of the alloy becomes observable with the increasing amount of NiMnGa in the composite. In addition, the diamagnetic PLA/PEG blend gained magnetic properties with addition of the alloy. It is also observed that NiMnGa had a positive effect on the shape memory feature of the polymer blend. [ABSTRACT FROM AUTHOR]

Polymer electrolytes have caught the attention of next-generation lithium (Li)-based batteries because of their exceptional energy density and safety. Modern society requires efficient and dependable energy storage technologies. Although lithium-based with good performance are utilized in many portable gadgets and electric vehicles (EVs), their potential for utilization is constrained by frequent fires and explosions. We discuss the fundamental properties and description of various polymer electrolytes, such as solid polymer electrolytes (SPEs), gel polymer electrolytes (GPEs), and composite polymer electrolytes, in this article (CPEs). We also describe significant advances in non-aqueous Li-based rechargeable batteries. The obstacles and possibilities for developing innovative polymer electrolytes for high-performance Li-based batteries are discussed. [ABSTRACT FROM AUTHOR]

In the present study, preparation, characterization and catalytic application of a novel ionic liquid/high-density polyethylene composite supported Mo complex (HDPE/IL-Mo) are reported. The HDPE/IL composite was prepared by grafting of 1-methyl-3-octylimidazolium bromide ([MOIm][Br]) on high-density polyethylene through the coacervation method. Then, molybdenyl acetylacetonate was immobilized on HDPE/IL to deliver HDPE/IL-Mo catalyst. The HDPE/IL-Mo composite was characterized by using PXRD, FT-IR, EDX, TGA and SEM techniques. This material was used as a powerful and efficient catalyst in the synthesis of bioactive pyrano[2,3-d]pyrimidines under solvent-free conditions. The products were obtained in high to excellent yields at short reaction times. The leaching and recovery tests were carried out to determine the nature of HDPE/IL-Mo under applied conditions. [ABSTRACT FROM AUTHOR]

The hydrogen, H, bonding, wettability and sorption behaviors of the poly(vinyl alcohol), PVA and tea polyphenols, TP, blended composites with various blending ratios were quantitatively evaluated. The H-bonding of PVA/TP composites has been found contributed from not only the pure PVA and TP, but also the formed composites and would be enhanced with the TP percent increase. The pure PVA has better hydrophilicity and the PVA/TP composites would enhance the hydrophobicity with the increase of TP percent. According to wetting results, the added TP percent at about 35% seeming to be a critical turning point for PVA/TP composites to change the wettability. The sorption of PVA/TP composites was greatly influenced by the pH of solution due to it greater in the base solution and smaller in the acid solution as comparison with the referenced water sorption. In all these cases, the sorption amount was basically reduced with the TP percent increase. [ABSTRACT FROM AUTHOR]

Poly(aryl ether sulfone) nanofiber with quaternary ammonium side chains (QPAES-90/10) was electrospun into bead-free nanofibers. The electrospun fibers were cross-linked to embed in an ionomer matrix while maintaining the intact fiber morphology. A series of characterization studies showed that cross-linked nanofibers profoundly affect the performance of membranes. As the result, the fiber membranes possess both enhanced mechanical properties and increased ion exchange capacity. The composite membrane exhibits lower swelling and better ion conductivity than membranes without nanofibers, suggesting that the nanofiber network containing quaternary amine groups promotes the formation of anion transport pathways. These films show lower methanol permeability and higher selectivity than the neat matrix. Therefore, this strategy of incorporating cross-linked and electrospun nanofibers into membranes is an effective method for developing anion exchange membrane material as a competitive candidate material for fuel cells. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA)/corn stover (CS) composites were prepared by melt blending different proportions of PLA and added CS. PLA was grafted with acrylic acid to improve the compatibility of the matrix with CS. PLA-g-AA interacted well with CS, resulting in a denser composite material with relatively satisfactory hydrophobic properties. The barrier and mechanical properties of composites were studied, and it was found that the barrier and mechanical properties of PLA-g-AA/CS composite materials were significantly improved, especially those with 30 wt% CS provided better tensile properties and elongation at break. The structure at the tensile section of the composite material was observed using SEM. The proper amount of CS had better dispersion in the matrix, and PLA-g-AA could further improve the interfacial bonding force. The crystallization and thermal properties of the composites were analyzed using XRD, DSC, and TGA, and the effect of the CS content on the crystallinity of composites was also studied. [ABSTRACT FROM AUTHOR]

In this work, porous chitosan/alginate hydrogels (CS/Alg) were fabricated by the addition of two reinforcing fillers, PHEMA/PEI core–shell particles and pineapple-leaf cellulose fibers, using a freeze-drying method. At the optimum ratio and mixing conditions, the porous hydrogels obtained after freeze-drying showed an interconnected porous structure with pore size in a range of 50–100 µm and porosity in a range of 80–85%. With the incorporation of PHEMA/PEI core–shell particles and pineapple-leaf cellulose fibers, the composite hydrogels (CS/Alg/PF) maintained their structure when submerged in deionized water and acidic and basic media, with low volume shrinkage. Water adsorption reached equilibrium within 30 min, and the percentage water uptake ratios of CS/Alg and CS/Alg/PF in deionized water increased from 1165% to 1391%, largely due to the presence of pineapple-leaf cellulose fibers. However, the presence of both PHEMA/PEI particles and pineapple-leaf cellulose fibers increased the compressive modulus of the resulting hydrogels from 0.028 MPa to 0.083 MPa. Moreover, the pineapple-leaf cellulose fibers improved the storage modulus of the hydrogels as revealed by dynamic mechanical analysis. CS/Alg/PF was also utilized as a template for loading silver nanoparticles (AgNP) through a reduction reaction of silver ions at ambient temperature without the use of any additional chemical reducing agents. The physico-mechanical properties and antibacterial activity of the AgNP-loaded CS/Alg/PF hydrogels were evaluated as well. [ABSTRACT FROM AUTHOR]

Polylactide is a highly demanded biopolymer, whose industrial application constantly increases. Its disadvantages such as brittleness and slow crystallization rate can be overcome by application of different additives. Because of environmental issues, using natural waste fillers as modifying agents for polylactide is especially interesting. In this study linseed cake, a byproduct of oil extraction from linseed, characterized by oil content of 0.9–39.8 wt.%, was added to polylactide to influence its crystallization behavior. The formation of the crystalline phase was studied by differential scanning calorimetry in isothermal and non-isothermal conditions and analyzed according to methods by Jeziorny, Ozawa, Mo and Avrami. The samples' microstructures were observed using polarized light microscopy. The crystallization rate and Avrami exponent of samples crystallized in different conditions were evaluated. It was found that addition of 10 wt.% of linseed cake containing at least 17.7 wt.% oil notably changes the crystallization of polylactide, increasing its crystallinity and promoting the growth of crystallites. [ABSTRACT FROM AUTHOR]

Considering the long-term structural stability of polymer-nanotube composites under different service conditions, we investigate the tensile creep of polymer-nanotube composites consisting of poly(methyl methacrylate) (PMMA) and multiwalled carbon nanotubes (MWCNTs). The PMMA is pre-irradiated by ultraviolet light with different doses to change the molecular weight. The creep deformation of the PMMA-MWCNT composites with the weight fraction of MWCNTs in a range of 0 to 0.7 wt.% in a temperature range of 50 to 80 °C is well described by a Maxwell standard model with parallel connection between a spring, E1, and a Maxwell element (a dashpot, η, in the series connection with a spring, E2). The value of E1 is a linear function of the inverse of the normalized weight fraction with the average values of the coefficients/constants for the linear relation being increasing functions of the weight fraction of MWCNTs. The value of η is a power function of the molecular weight with a power index of ~3.3. The activation energy for the creep deformation of the PMMA-MWCNT composites increases with the increase of the weight fraction of MWCNTs. [ABSTRACT FROM AUTHOR]

In this study, polyurethane was blended with silica aerogel to improve its thermal insulation property. The silica aerogel/polyurethane composite with a suitable composition 35/65 (v/v) has low thermal conductivity (0.13 W/m K) and a hydrophobic property (water contact angle of 95.6°). The pore size, pore distribution, and structure of silica aerogel (tetraethoxysilane-based) were studied to select the suitable silica aerogel for blending. The co-precursor method and the solvent exchange method were used to prepare the silica aerogel for comparison. Fourier Transform Infrared spectra confirmed that the co-precursor method created more Si-CH groups on the silica surface than solvent exchange method. The silica aerogel prepared by the co-precursor method had a thermal conductivity of 0.032 W/m K with a porosity of 97 %, and a water contact angle of 130°. This silica aerogel prepared was then used to blend with the polyurethane prepared by diisocyanate and poly (tetramethylene oxide), with 1,4-butanediol (1,4-BD) as the chain extender. Silica aerogel/polyurethane composites were formed as films of various compositions by the solvent casting method. Scanning electron microscopic (SEM) photographs revealed that the composites were uniform. The optimal composition of silica aerogel/polyurethane is 35/65 (v/v) with the water contact angle of 95.6° and the thermal conductivity 0.13 W/m K. The silica aerogel/polyurethane composites have no disadvantages of brittleness and hygroscopic property, and possess a low thermal conductivity property. [ABSTRACT FROM AUTHOR]

The aim of the present work was to improve the properties of poly(trimethylene terephthalate) (PTT) by forming composites with silica (SiO) and multiwalled carbon nanotubes (MWCNTs). Inorganic fillers were pretreated using an in-situ sol-gel process, and then silica particles were attached to the surfaces of the multiwalled carbon nanotubes (SiO-MWCNTs). Maleic anhydride (MA) grafted with PTT (PTT- g-MA) and silica-multihydroxyl-functionalized MWCNTs (SiO-MWCNTs-OH) were used to improve the compatibility and dispersibility of the MWCNTs within the PTT matrix. The composites were characterized morphologically by transmission electron microscopy and chemically using Fourier transform infrared spectroscopy, C solid-state nuclear magnetic resonance, and ultraviolet-visible spectroscopy. The PTT- g-MA/SiO-MWCNTs-OH (1 wt.%) composite exhibited significantly improved thermal properties. The functionalized PTT- g-MA/SiO-MWCNTs-OH composite also showed markedly enhanced antistatic properties. The optimal proportion of SiO-MWCNTs-OH in the composite was 1 wt.%; adding more than this compromised the compatibility between the organic and inorganic phases. [ABSTRACT FROM AUTHOR]

A new kind of ZrTiO filled polytetrafluoroethylene (PTFE) microwave composite substrates was fabricated through the hot-pressing process. The microwave dielectric properties of ZrTiO/PTFE composites were measured using stripline resonator method. The relative dielectric constant ( ε) and loss tangent (tan δ) of the composites increase with an increase of the volume fraction of ZrTiO ceramic (0-46 vol%). The experimental dielectric constants of the composites match well with theoretically predicted values by Lichtenecker mixing rule. As the volume fraction of ZrTiO ceramic increases, the thermal expansion coefficient and the temperature coefficient of dielectric constant decrease. The ZrTiO filled PTFE composite exhibits a dielectric constant of 7.42 with a loss tangent of 0.0022 (10 GHz) at an optimum filler loading of 46 vol%. [ABSTRACT FROM AUTHOR]

Innovative polypropylene composites were prepared using as a biofiller, wool keratin hydrolizates obtained by a green process with superheated water in a microwave reactor. To promote the affinity between the hydrophobic polymer and the biofiller, maleic anhydride grafted polypropylene was used as a compatibilizer. The composites showed a homogeneous dispersion of the keratin particles in the polymer matrix. The thermal properties and the structure of the composites were investigated in dependence of keratin loading and crystallization conditions. The keratin particles had a heterogeneous nucleating action on polypropylene crystallization that increased the overall crystallization rate. The nucleation density increased as a function of the keratin amount in the composites. The crystallinity, the crystal dimension and the long period of the polypropylene were found to be dependent on the crystallization condition and the composite composition. In the crystallized composites, the keratin component, having dimension in the nano- and micro-scale length, was relegated to the intraspherulitic and/or interspherulitic polypropylene regions. [ABSTRACT FROM AUTHOR]

In this study, effects of various types of functional polyolefin copolymers (FPOCs), poly(isobutylene- alt-maleic anhydride), poly(maleic anhydride- alt-1-octadecene) and poly(ethylene- graft-maleic anhydride), on the microstructure formation, interfacial interaction and physical properties of cyclic olefin copolymer (COC)/graphite composites were investigated. The COC/graphite composites were prepared in a lab. scale twin screw extruder. Microstructural features of samples were studied in a field emission scanning electron microscopy (FESEM). Viscoelastic properties of samples, obtained from the rheology tests in melt state and the dynamic mechanical analysis in solid state were used to quantify interfacial interactions between the COC and graphite depending on the types of FPOC. The average aspect ratio ( A) values of graphite flakes in the COC phase were determined about 40-65 by SEM observation and image analysis study on the samples prepared with different types of FPOC. Based on the gas permeability measurements, tortuous diffusion model suggested that the A values of graphite flakes varied between 40 and 80 depending on the amount of graphite. It was shown that the poly(isobutylene- alt-maleic anhydride) copolymer provided relatively higher interfacial interaction between the COC and graphite flakes than the other FPOCs. [ABSTRACT FROM AUTHOR]

The preparation of microcapsules with adequate performance is required for the fabrication of self-healing composites. Self-healing microcapsules with improved morphology as well as thermal and water resistance were prepared by introducing either single-walled carbon nanotubes (SWCNTs) or aluminum oxide nanoparticles (nano-alumina) into a urea-formaldehyde resin (which acts as the wall material). The prepared microcapsules were studied using various characterization techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), optical microscopy (OM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and contact-angle measurements. Based on comparisons with traditional poly(urea-formaldehyde) microcapsules, the modified microcapsules exhibited a smoother surface. Our results indicate that the presence of the nanoparticles did not affect the core content of the microcapsules, which was approximately 78 wt.%. The average size of the traditional microcapsules was reduced from 168 μm to 115 and 95 μm for the SWCNT- and nano-alumina-modified microcapsules, respectively. In addition, the thermal resistance of the microcapsules was improved after modifying the capsule walls. After the microcapsules had been modified with SWCNTs, the water resistance of the capsules improved, and the contact angle increased from 44° to 50°. [ABSTRACT FROM AUTHOR]

The concentration dependence of optical, thermophysical and electrical behavior, based on poly-methyl methacrylate filled with CdSe quantum dots (PMMA(CdSe)) have been investigated. The PMMA(CdSe) concentration was 0.001, 0.005, 0.01 and 0.05 wt.%. The composites were prepared in the form of films by the solution casting technique. The optical properties of PMMA(CdSe) films have showed that, there is a red shift of the absorption and photoluminescence (PL) after the QDs were added into PMMA. The PL peak intensity of the composite was enhanced by ≈ 2.5 times compared to the CdSe QDs. The thermal conductivity (k) was obtained by measuring the thermal diffusivity (α) and thermal effusivity (e) using the photoacoustic (PA) technique. The composites exhibit ≈ 120 % improvement in k at 0.05 wt.% . Furthermore, the dc electrical conductivity measurements of pure and doped PMMA, showed that the obtained values were enhanced about four orders of magnitude for the highest concentration compared with pure PMMA at 500 C. [ABSTRACT FROM AUTHOR]

novel poly[(1,2-ethylenediamino) (2-hydroxy-1,3-propanedily) chloride]/ Laponite/polyacrylic acid (PEDAECH/Laponite/PAA) hydrogel was synthesized by two-step solution polymerization combining nanocomposite (NC) strategy with double network (DN). The structural characteristics of resulting hydrogels were investigated by Fourier Transform infrared spectrum (FTIR) and Transmission Electron Microscopy (TEM). A core shell structure was observed in PEDAECH/Laponite composite. The swelling and mechanical strength of the resulting hydrogels were measured when PEDAECH/Laponite composite dose varied. The novel hydrogel achieved a high compressive stress of 148.0 KPa even in higher water content of 98.7% when the PEDAECH/Laponite composite dose is 0.05 ml, the dose of AA was 3.6 ml, N, N′-methylenebisacrylamide (MBAM) dose was 0.04 wt% (based on the weight of AA) and reaction temperature was 0 °C, Based on the cyclic compression studies, there is a small decline in the maximum stress of the hydrogels at the fixed strain of 45% even under three cyclic compressions. [ABSTRACT FROM AUTHOR]

This article reports a new way to prepare expandable graphite using a hydrothermal method. Natural flake graphite was added to a concentrated sulfuric acid and nitric acid mixture in a flask with mechanical stirring at room temperature. This was then placed in a Teflon-lined autoclave. The autoclave was sealed and quickly heated to the desired temperature, where it was maintained for 1 h before it was cooled to room temperature. The results showed that the expanded volume of EG obtained using the hydrothermal method was higher than those of EGs obtained through conventional liquid phase synthesis and ultrasound irradiation for the same acid concentrations in the mixture. X-ray diffraction patterns were used to analyze the structure and confirm that expandable graphite had indeed been prepared. A scanning electron microscope was utilized to observe the morphologies of the expandable graphite and expanded graphite. A cone calorimeter was used to investigate the flame-retardant properties of the halogen-free composites. The data show that the peak HRR values of the composites containing 30 wt% EG are dramatically lower than those of the pure HDPE resin and composites containing 30 wt% NG. The residual mass increases to 8.0 wt%, 30.1% and 37.6%, respectively, for pure HDPE, 30 wt% NG composites and 30 wt% EG composites. These results show that the HDPE/EG composite possesses excellent flame-retardant and thermal properties. [ABSTRACT FROM AUTHOR]

In this study, the atmospheric plasma has been used to modify the surface of polyterafluoroethylene (PTFE). Helium (He) and argon (Ar), different plasma powers, and different rolling rates were investigated by measuring the contact angle. The optimizing conditions are: Ar gas, 1.3 kW power, and 2 L/min rolling rate. The functional group OH was observed at the peak of 3,476 cm in Attenuated total reflection-Fourier-transform infrared spectrometry (FTIR-ATR). The PTFE has contained oxygen after surface modification and has been proofed by X-ray photoelectron Spectra (XPS). Three silanes have been used to modify the surface of glass fiber cloth (GFC). These silanes are Benzylamino-silane (A1128), N-[2-Vinylbenzyl]-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride oligomer (KBM974), and 3-trimethoxysilyl propryl methacrylate (KBM503). Different concentrations of silanes and dipping methods were studied. It is better for GFC to stick with glue by using 1% KBM503. Two glue series of N and J were used to adhere the modified PTFE and GFC by using UV curing. N series is Aliphatic Urethane Diacrylate diluted in 25% IBOA and J series is Aliphatic Urethane Diacrylate. The PTFE/GFC composite formed by using N series has the strip strength of 0.712 MPa, and the hundred square strength of 95%. The result is about 5 times better comparing with the unmodified PTFE/GFC. The surface after stripping was observed by using scanning electron microscope (SEM). [ABSTRACT FROM AUTHOR]

This work explores the possibility of using cork for reinforcing of polypropylene (PP). The cork granules were mixed with PP by extrusion and the mixture was then injected. The hydrophilic character of cork and the hydrophobic character of PP influence negatively the adhesion at the interface between the reinforcement and the matrix. In order to improve it, several chemical modifications of the cork reinforcements were used in this work: treatment with silane, with sodium hydroxide and with a compatibilizing agent MAPP. The interface modifications were studied by scanning electron microscopy (SEM), Goniometry analysis and infrared spectroscopy analysis (IR). The improvement of the mechanical properties was demonstrated by tensile tests. On their basis it was demonstrated that the best interfacial adhesion between cork and PP is achieved by the silane chemical modification (silanization). [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotube/Polyacrylonitrile (MWNT/PAN) composite nanofibers were prepared by electrospinning technique, whereby functionalized MWNTs (F-MWNTs) and pristine MWNTs (P-MWNTs) were used as reinforcing materials. The F-MWNTs were functionalized by Friedel-Crafts acylation, which introduced aromatic amine (COC6H4-NH2) groups onto the sidewall. The diameter range of the PAN nanofibers was 400-100 ± 50 nm. The beads formation was also observed when the amounts of MWNTs were increased in the PAN solution. The bead formation in F-MWNT/PAN composite nanofibers was less as compared to P-MWNT/PAN. The MWNTs were embedded within nanofibers and were well oriented along the nanofiber axis, as confirmed by transmission electron microscopy. The mechanical and thermal properties of the PAN nanofibers were improved by the incorporation of MWNTs. [ABSTRACT FROM AUTHOR]

The nano-SiO2 is used to modify the waterborne polyurethane, and the morphology and performance of the waterborne polyurethane (are studied in) prepared by the in-suit polymerization method and the blending method. The properties and structure have been characterized by fourier transform infrared spectra (IR), differential scanning calorimetry (DSC), Thermal gravimetric (TG), transmittance electron microscopy (TEM) and Dynamical Mechanical Analysis(DMA). The experiment results show that, compared with the blending method, the in-suit polymerization has more advantages in that the nano-SiO2 is evenly dispersed in the waterborne polyurethane, obviously in microphase separation and better in resistance to high temperature and water. [ABSTRACT FROM AUTHOR]

Solid-state organic batteries based on charge-transfer complexes have been extensively used. However, the low mechanical strengths of these materials have restricted their applications. The polymer composite of these materials have been prepared and used in fabrication of solid-state batteries to overcome this problem. The pressed pellets of the polymer composite of o-tolidine–iodine (1:0.75) charge-transfer complex in poly(vinyl chloride) and polystyrene have been used as cathodes in contact with zinc as anode metal. The electrochemical characterization of these cells such as open-circuit voltages, short-circuit currents, their time and temperature dependence and rechargeability of these cells have been studied. The impedance analyses have been done to understand the nature of the electrode reaction. [ABSTRACT FROM AUTHOR]

The effects of chemical surface treatment on PBO fiber and its composite materials were investigated using a basic sodium hydroxide solution. We evaluated several important treatment parameters quantitatively, including treatment concentration, treatment temperature and treatment time. Both as-spun (AS) and high-modulus (HM) PBO fibers were studied. The results showed that PBO fibers exhibited minimum or negligible reduction in their tensile strengths after the proposed treatment processes. The fibers’ contact angles with several liquid media were greatly reduced and the surface free energy could be increased to 58 mJ/m2 or by 17%. The interfacial shear strength between PBO fiber and the epoxy matrix was improved to 38 MPa or by 11% with the same treatment process. The composite’s failure mode also shifted from fiber/matrix interface adhesive failure to partly cohesive failure. [ABSTRACT FROM AUTHOR]

A study on PTFE reinforced with SiO2 was described. This study included the manufactural process of SiO2-reinforced PTFE and the effects of the content of silane (Z6124) on the properties of the composites material, such as thermal, dielectric properties, tensile strength and morphology, etc. PTFE/silica composites of 60 wt% SiO2 loaded with a different coupling agent content were mixed by a high-speed dispersion machine and prepared by a two-roll milling machine. Our results show that the sample treated with 3 wt% silane has the highest tensile strength and optimum dielectric properties. Furthermore, the tensile strength and coefficient of thermal expansion (CTE) increase, and the water absorption decreases, with an increasing silane content. These experiments reveal that silane treatment can reduce the overall hydrophilicity of the composites. Finally, predictions on dielectric and CTE properties are discussed. It has been found that experimental values of the dielectric constant agree well with those predicted by the rule of mixture. [ABSTRACT FROM AUTHOR]

A study on PTFE reinforced with SiO2 was described. It included the manufacturing process of SiO2-reinforced PTFE and the effects of the SiO2 content and size on the properties of the composite material, such as thermal, dielectric, tensile strength and morphology, etc. PTFE/SiO2 composites loaded with two sizes (5 µm or 25 µm SiO2) of filler contents varied from 0–60 wt% were mixed by a high-speed dispersion mixer and made via a two-roll milling machine. Our results showed that the composite filled with 25 µm SiO2 at 60 wt% filler content had the highest modulus, lowest CTEz and acceptable dielectric properties. Composites with different sizes of filler showed a similar trend of decreasing tensile strength and coefficient of thermal expansion (CTEz), and increasing tensile modulus, water absorption and dielectric properties as the filler content increased. Furthermore, the composites filled with small-size filler showed higher water absorption and dielectric loss properties due to the presence of higher SiO2 surface area. Poor adhesion between filler and matrix is a primary cause of low tensile properties and lack of increase in thermal stability. Such phenomenon was also confirmed by fracture surface analysis of scanning electron microscope (SEM). Experimental data were compared with theoretical models from the literatures, which are used to predict the properties of two component mixtures. The results revealed that experimental values of dielectric constant and CTEz agreed with the theoretical calculated values. It was also found that the modified Nicolais–Narkis equation provided a good estimation for the tensile strength of composite. [ABSTRACT FROM AUTHOR]

Wounds exhibit varied behaviour and types and each type has its own differential healing requirements. This realization has encouraged the development of various wound dressings, each with specific characteristics. In the present study, composite hydrogels composed of PVA/Pullulan/Poly-L-Lysine/Gelatin (P/Pu/L/G) were fabricated using the freeze-thawing method with the aim of achieving enhanced wound healing. The hydrogels were evaluated for their physicochemical and in vitro biological properties. The morphological evaluation using SEM revealed the porous three-dimensional structure exhibited by the P/Pu/L/G hydrogels. The wettability and chemical composition of the hydrogels was elucidated by contact angle and ATR-FTIR analysis respectively, where the contact angle measurements showed an increase in the hydrophilicity of P/Pu hydrogel upon the incorporation of Poly-L-lysine and Gelatin. The results of in vitro hemolysis assay showed better blood compatibility of the fabricated hydrogels while the protein adsorption study revealed a 2.3-fold increase in the protein adsorption on the P/Pu/L/G hydrogels as compared to PVA hydrogels. The composite P/Pu/L/G scaffolds exhibited a 2-fold increase in the cell viability on day 7, when compared to the control; while the results of the scratch assay where complementary to the cell viability assay, which affirmed improved cell migration and proliferation in the presence of P/Pu/L/G hydrogels. The overall results of physicochemical characterization and biological evaluation advocates the potential of the composite hydrogels of P/Pu/L/G for biomedical applications such as wound dressing. [ABSTRACT FROM AUTHOR]

A series of novel hydrophilic organic-inorganic composites (OIC) with enhanced sorption properties were synthesized by one-pot synthesis technique - in situ radical polymerization of acrylamide (AM) and hydrolytic polycondensation of sodium silicate in aqueous solution. Formation of mixed organic-inorganic polyacrylamide (PAM)/SiO2 phase has been detected by FTIR spectroscopy (appropriate changes in H-bonds network structure of PAM) and DSC analysis (dramatic decreasing glass temperature of PAM). Additive decreasing of mass loss of OIC with increasing of SiO2 content is explained by the increasing of PAM-content in mixed PAM/SiO2 phase on the interface of organic and inorganic phases. The formation of SiO2 aggregates with different dispersity, which, in their turn, form submicron structures in composites with SiO2 content more than 15 wt.% was observed from SEM data. Structurization of OIC resulted in the enhanced sorption characteristics (swelling capacity of the OIC reaches 2730%). Sorption kinetic curves obtained both in isothermic and isochoric regimes demonstrate that the swelling process of OIC is limited by relaxation of PAM chains and can be described by sorption mechanism of Type II. [ABSTRACT FROM AUTHOR]