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The preparation of polyimide matrix composites with low curing temperature and high mechanical properties is of great importance. In this study, a low‐cost and multi‐functional nanofiller, 5‐aminobenzimidazole grafted graphene oxide (5‐ABZ@GO) has been designed. By nucleophilic attack on 5‐aminobenzimidazole basic groups and doping of GO, the above requirements of polyimide composites were skillfully realized. The results show that when the addition of 5‐ABZ@GO is 1%, the 5‐ABZ@GO/PI nanocomposites can achieve complete imidized at 200°C. Moreover, the nanocomposite prepared by imidization at 200°C has good mechanical and thermal properties (tensile strength is 141.64 MPa, modulus is 6.05 GPa, T5% is as high as 543.5°C), which is better than the PI composites prepared at 320°C. This study provides an innovative approach to preparing polyimide composites that meet mechanical performance requirements while utilizing comparatively lower curing temperatures, low curing temperature polyimide resins provide a new path for integrated composites with structure–function integration. [ABSTRACT FROM AUTHOR]

This study presents the eco-friendly composites coating with advanced properties that are prepared by chitosan (CS)-modified graphene oxide (GO) filled acrylic-based coating. Photo-curable acrylic-based nanocomposite containing different amounts of chitosan-modified graphene oxide (CS–GO) and the effect of CS–GO on the coating morphology, UV-curing, transparency, tribological, antimicrobial, thermal and anticorrosion properties was studied. The curing study confirmed that the CS–GO absorbed photon but did not affect the final conversion of the coatings. The results of corrosion analysis demonstrated that the CS–GO filled nanocomposite coatings have higher corrosion protection ability than that of pure acrylic and GO filled coatings. The antimicrobial properties of CS–GO filled coating showed that the antimicrobial performance enhanced as the concentration of CS–GO increased. The optical transmittance study shows that the coating's film transparency decreased with increasing CS–GO concentration, but all of the nanocomposite coatings have a high visible transmittance. This study attributes the enhanced properties to the dispersion of the chitosan-modified GO, which greatly improved the interfacial strength of CS–GO and polymeric matrix and enhanced corrosion properties. [ABSTRACT FROM AUTHOR]

Herein, graphene oxide (GO) and its derivative, reduced GO (rGO) and p‐phenylenediamine (PPD) functionalized GO (GO‐g‐PPD) were first synthesized and selected as dielectric fillers, and then GO/polyimide (PI), rGO/PI, and GO‐g‐PPD/PI dielectric nanocomposites were fabricated through in situ polymerization‐composition strategy. Fourier transform infrared, Ram, and x‐ray diffraction analysis confirmed the success synthesis of rGO and GO‐g‐PPD dielectric fillers. The mechanical properties showed that GO‐g‐PPD/PI nanocomposites exhibited the highest tensile strength and elasticity modulus. TGA analysis revealed that the enhancement of thermal stability by addition of dielectric fillers. The dielectric constant of 2.5 wt.% GO‐g‐PPD/PI nanocomposites reached 25.05, which was 8.55 times that of pure PI (2.93). Energy storage performance tests showed that the energy storage density of GO‐g‐PPD/PI containing 2 wt.% filler reached 0.77 J/cm3, which was 71% higher than pure PI. These findings underscore the potential of GO derivative as a cost‐effective reinforcement for PI dielectric nanocomposites for high‐temperature capacitive energy storage applications. [ABSTRACT FROM AUTHOR]

The combination of cellulose nanocrystals (CNCs) with synthetic polymers like polypropylene (PP) offers the opportunity to create advanced nanocomposites with significant advantages in terms of mechanical properties, improved thermal stability, enhanced barrier properties, and sustainability. However, a major drawback for incorporation of CNCs in polymer matrices is their poor dispersion and incompatibility with industrial processing of many composites. This work aims to improve the dispersion of hydrophilic CNCs in a hydrophobic matrix using a method which could be adapted for the industrial level. CNCs are extracted from Ampelodesmos mauritanicus (El Diss plant) (CNCD) and incorporated in a polypropylene matrix using the masterbatch method. A first nanocomposite (PP/CNC-Gr) was prepared by adding maleic anhydride (MA) to a CNCD/PP suspension, while the second nanocomposite (PP/CNC-Co) was achieved by using a MA-grafted PP (PP-g-MA) as a third component. Concentrated masterbatch underwent solution casting followed by homogenization in a Brabender mixer. Mechanical properties comparison showed that PP/CNC-Co nanocomposites exhibited greater resistance relatively to PP/CNC-Gr nanocomposites. Moreover, PP/CNC-Co nanocomposites revealed an improved thermal stability and a higher complex viscosity, particularly with 3% of CNCD. Properties enhancements are attributed to the reaction between MA groups grafted to PP chains and hydroxyl groups of CNCDs, which enables an improved interfacial adhesion, leading to more continuous materials, as perceived from the increase in viscosity and morphology observation. On the other hand, MA reaction with PP chains and CNCD induced only a partial coverage of CNCDs during nanocrystals treatment, conferring relatively lower properties to PP/CNC-Gr nanocomposites. [ABSTRACT FROM AUTHOR]

Stereolithography (SLA) is a highly versatile additive manufacturing technique that utilizes various ink formulations to fabricate 3D-printed nanocomposite structures with desired properties. Zinc oxide (ZnO) is a promising candidate due to its excellent mechanical and thermal stability, and compatibility with various polymeric matrices. In this work, varying ink formulations containing ZnO nanoparticles, along with employing appropriate post-printing curing parameters to fabricate SLA 3D-printed acrylate-based nanocomposites with improved mechanical and thermal properties, were reported. This study can significantly contribute to expanding its potential use in practical applications such as biomedical and structural applications. [ABSTRACT FROM AUTHOR]

The miniaturization and high-power density of modern electronic devices pose significant thermal management issues, particularly affecting their performance and lifetime. Ladder-like polysilsesquioxanes (LPSQs) offer a promising solution due to their remarkable thermal, mechanical, and chemical properties. By incorporating thermally conductive fillers, LPSQ composites can achieve high thermal conductivity (TC), making them ideal for thermal management in advanced electronic applications. In this study, LPSQ-based nanocomposites containing functionalized alumina nanoparticles were prepared by solution casting and UV curing, and the effects of varying amounts of Irgacure-184 photoinitiator on their structural and thermal properties were investigated. Three sets of samples were prepared with a fixed amount of LPSQs, 80 wt.% of nanoparticles, and 1, 5, or 10 wt.% of photoinitiator with respect to the matrix. TC was evaluated from the measured values of heat capacity, density, and thermal diffusivity. TC values increased by 60%, 71.2%, and 93.1% for the three samples, respectively, compared to the neat matrix. Results indicate that an intermediate amount of photoinitiator (5%) preserved LPSQs' structural integrity, namely the presence of long linear silsesquioxane chains, and provided good filler dispersion and distribution, high polymerization degree, thermal stability, and high TC. [ABSTRACT FROM AUTHOR]

Polybutylene terephthalate (PBT) nanocomposites were melt-blended with two types of Turkish halloysite nanotubes (HN). Naturally occurring HN samples were used to produce PBT-based composites at the HN compositions of 1%, 3%, 5%, and 10%. Findings of neat and silane-coated HN-containing composite samples were compared to investigate the interfacial adhesion between polymer matrix and reinforcement material. According to test results, a 1% amount of HN was found to be the most suitable option in the case of mechanical and thermal properties of composites. Additionally, silane-modified grade displayed highly indicative improvements compared to pristine HN clay due to better interfacial adhesion of halloysite nanotubes to the PBT matrix was accomplished. Property enhancements achieved for composite samples containing low contents of HN were confirmed by morphological examinations. As a result, the PBT/ 1% HN-S composite sample was bookmarked as the most suitable option to fabricate HN-reinforced PBT-based nanocomposites in terms of mechanical, thermo-mechanical, morphological, thermal, and physical performances based on the findings in this study. Silane-modified halloysite grades exhibited better results, and they were found to be more suitable in the case of applications of PBT. [ABSTRACT FROM AUTHOR]

The combination of silicone rubber (SR) and ethylene‐propylene‐diene monomer (EPDM) could have an aggregate of their properties. High temperature vulcanized (HTV) is one of the most widely used SR type. This study explores the impact of montmorillonite Cloisite® layered silicate nanoclay on the vulcanization characteristics, mechanical‐dynamical behavior, and thermal properties of the HTV/EPDM blend. For this purpose, varying ratios of the HTV/EPDM compounds were prepared in the range of 100/0, 50/50, and 0/100, with 0, 3, and 5 wt% of Cloisite® using an internal mixer. The X‐ray diffraction results indicate that the mixing time, Cloisite® content and base polymer significantly influence the distance between Cloisite® layers. Cloisite® was found to accelerate the curing system and reduce the difference between minimum and maximum torque. The mechanical analysis of the prepared HTV/EPDM/clay nanocomposites revealed an increase in hardness, tensile strength, and modulus for samples with applied Cloisite® content. The degradation temperature was raised in HTV base samples by the presence of Cloisite®. On the other hand, the degradation temperature was dropped in the EPDM base samples as the amount of Cloisite® increased. In the HTV/EPDM/clay compounds, the degradation temperature was between the degradation temperatures of pure HTV and EPDM rubbers. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development of polymer‐based dielectric nanocomposites with superior dielectric properties, heat dissipation, and excellent thermal stability remains a significant challenge for advanced electronic and electrical systems. In this work, boron nitride nanosheets (BNNS) and MgAl layered double hydroxide nanosheets (MgAl LDHNS) were utilized as binary fillers and incorporated into polyetherimide (PEI) to fabricate BNNS‐MgAl LDHNS/PEI nanocomposite films by ball milling dispersion and solution casting method. Owing to the exceptional synergistic effect of BNNS with high thermal conductivity and large diameter, combined with MgAl LDHNS with high dielectric constant and small diameter, the dielectric constant and thermal conductivity of the nanocomposite film were enhanced while maintaining low dielectric loss and high breakdown strength. For the BNNS‐MgAl LDHNS/PEI nanocomposite films with filler loading of 12 wt%, the dielectric constant (6.47 at 100 Hz) increased by 73%, the in‐plane thermal conductivity (6.932 W/m·K) and through‐plane thermal conductivity (0.407 W/m·K) increased by 561% and 111%, respectively. And the breakdown strength of the nanocomposite film remains at 82.1 kV/mm. Simultaneously, the thermal stability and mechanical flexibility of the nanocomposite film were maintained. This work presents a promising PEI‐based composite material and offers new insights into the role of two‐dimensional binary fillers with varying sheet diameters in enhancing the properties of polymer‐based composites. Highlights: BNNS‐MgAl LDHNS/PEI nanocomposite film was prepared.The nanocomposite film has high dielectric and thermal properties.The interfacial polarization synergistic enhanced by the 2D binary fillers.A high thermal conductivity path was formed between 2D binary fillers. [ABSTRACT FROM AUTHOR]

The copolymer precursor, poly [4-(4-vinylbenzyl)oxy)phthalonitrile]-co-methyl methacrylate (poly (VBOPN-co-MMA)), was synthesized through copolymerization of VBOPN and MMA at a temperature of 110°C. Subsequently, a single-chain polymer complex of cobalt phthalocyanine (SCP-CoPc) was formed at 150°C by intramolecular macrocyclization between the cobalt and the phthalonitrile group in poly (VBOPN-co-MMA), using excess cyclohexanol. The formation of the SCP-CoPc complex was confirmed through various spectroscopic techniques such as UV/Vis, FT-IR, 1H-NMR, and 13C-NMR. In particular, the disappearance of -CN band at 2232 cm−1 from FT-IR indicated the formation of the SCP-CoPc complex, while the presence of specific absorption bands in the UV/Vis spectrum further confirmed its creation. The electrical, dielectric, optical, and thermal properties of the SCP-CoPc complex and SCP-CoPc/ZnO 5% composites were investigated. The SCP-CoPc/ZnO 5 wt% nanocomposite exhibited improved dielectric and DC conductivity with increasing temperature. The activation energy (Ea) was found to be 0.35 eV for SCP-CoPc and 0.25 eV for SCP-CoPc/ZnO 5 wt% nanocomposite, indicating that the electrical conductivity followed the Arrhenius equation. The optical properties, including band gap, dielectric constant, and refractive index, were calculated for the SCP-CoPc/ZnO 5 wt% nanocomposite. The SCP-CoPc complex possessed a band gap of 2.89 eV, while the SCP-CoPc/ZnO 5 wt% nanocomposite had a slightly reduced band gap of 2.36 eV. The refractive indices of SCP-CoPc and SCP-CoPc/ZnO 5 wt% were also determined. [ABSTRACT FROM AUTHOR]

The green and environmentally friendly cardanol epoxy resin has a bright application prospect, but its insufficient thermal/mechanical properties seriously hinder its application. Adding nanoclay to polymer matrix is an effective method to enhance the thermal/mechanical properties of material, but the dispersion and compatibility of nanoclay in epoxy resin remain to be solved. In this work, active Girard's reagent clay (PG-clay) and non-active Girard's reagent clay (NG-clay) were prepared by using acethydrazide trimethylammonium chloride (Girard's reagent) as the modifier, and cardanol epoxy resin/G-clay nanocomposites were synthesized by the "clay slurry composite method". The results showed that both PG-clay and NG-clay were dispersed in the epoxy matrix in the form of random exfoliation/intercalation, which effectively improved the thermal/mechanical properties of the composites. Tg of the cardanol epoxy resin has raised from 19.8 °C to 38.1 °C (4 wt.% PG-clay). When the mass fraction of clay is 4%, the tensile strength of the non-reactive NG-clay increases by 128%, and the elongation at break also increases by 101%. Simultaneously, the active PG-clay can participate in the curing reaction of epoxy resin due to the amino group, forming a chemical bond between the clay layer and the resin matrix and establishing a strong interfacial force. The tensile strength of the composite is increased by 970%, and the elongation at break is also increased by 428%. This research demonstrates that the cardanol epoxy resin/G-clay nanocomposite stands as a highly promising candidate for bio-based epoxy resin materials. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of nanocomposites composed of three ratios of epoxy/graphene nanoplatelets (GNPs) by weight. The 0.1, 0.2, and 0.3 wt.% specimens were carefully manufactured, and their mechanical and thermal conductivity properties were examined. The tensile strength and modulus of epoxy/GNPs were enhanced by the large surface area of graphene nanoplatelets, causing crack deflection that created new fracture fronts and friction because of the rough fracture surface. However, the compressive strength was gradually reduced as GNP loading percentages increased. This was probably due to severe plastic yielding on the epoxy, leading to catastrophic axial splitting caused by premature fractures. Furthermore, the highest thermal conductivity was 0.1283 W/m-K, representing a 20.92% improvement over neat epoxy (0.1061 W/m-K) when 0.3 wt.% GNPs were added to the epoxy. This was because of efficient heat propagation in the GNPs due to electron movement through percolative paths. The tensile failure mode in epoxy/GNP nanocomposites showed a few deflected and bifurcated rough cracks and brittle, dimple-like fractures. Contrarily, compressive failure mode in GNP-added epoxy showed plastic flexural buckling and brittle large-axial splitting. The epoxy/GNP nanocomposites were considered a damage-tolerant material. [ABSTRACT FROM AUTHOR]

In the global context of environmental awareness, the present research proposes a sustainable alternative to the widely used petroleum-based epoxy coatings. Epoxidized corn oil (ECO) was tested as potential matrix for advanced nanocomposite coating materials reinforced with 0.25 to 1 wt.% single-walled carbon nanotubes (SW) with carboxyl and amide functionalities. The elemental composition of the epoxy networks was monitored by XPS, showing the increase of O/C ratio to 0.387 when carboxyl-functionalized SW are added. To achieve sustainable composite materials, citric acid was used as curing agent, as a substitute for conventional counterparts. The influence of both surface functional groups and concentration of SW was evaluated through structural and thermo-mechanical analysis. The progressive increase of the DSC enthalpy for SW formulated systems indicates a possible pattern for specific interactions within the bio-based epoxy translated by adjusted activation energy. For 1% neat SW addition, the Ea values decreased to 46 kJ/mol in comparison with 53 kJ/mol calculated for neat epoxy. Furthermore, the -COOH groups from SW nanostructures exerted a strong influence over the mechanical performance of bio-epoxy networks, improving the crosslinking density with ~ 60% and twofold the storage modulus value. Accordingly, by gradual addition of SW-COOH filler within the ECO-based formulations, a very consistent behaviour in seawater was noted, with a 28% decreased value for the absorption degree. [ABSTRACT FROM AUTHOR]

The importance of polymer-polymer thermoplastic composites is increasing due to ease of recycling. This work investigates the effects of remolding temperature and thermal annealing on the properties of polyethylene (PE) composites containing PA6 and GO/PA6 electrospun nanofibers. Nanocomposite samples were prepared by sandwiching several layers of PA6 or GO/PA6 electrospun mats and PE films in a hot press and subsequently were remolded at varying higher temperatures in a range of 180 to 210°C. Furthermore the remolded samples at 200°C were then annealed at 100°C for 10 h. SEM and DMTA results of the developed samples showed that the application of higher remolding temperatures, close to the melting point of PA6, improves wettability and interfacial strength in the composites. The DSC results of the samples revealed a slight increase in PE crystallinity due to the induced crystallization on the surface of nanofiber mat. It was also observed that an increase in the remolding temperature increases the tensile properties of the composites with the best properties obtained at a remolding temperature of 200°C. Increasing the remolding temperature beyond 200°C decreases the tensile properties of the composites due to melting and geometry degradation of the nanofibers. The results revealed that the annealing of the samples at 100°C for 10 h increases the degree of crystallinity and tensile properties. The highest yield strength, 16.4 MPa, and modulus, 277 MPa, were obtained for the composite containing 10.5 wt% of pure PA6 nanofibers. The elongation and toughness of this composite compared to those of pure matrix were increased by 61% and 83%, respectively. In the remolded and annealed nanocomposites, a crystalline region, as thick as 20 microns, grown on the surface of the nanofiber mat or nanofiber rich region, so called transcrystalline region, was observed by polarized reflected light microscopy. [ABSTRACT FROM AUTHOR]

Polymethyl methacrylate (PMMA) with varied compositions of copper oxide (CuO) nanoparticles was synthesized using in‐situ free radical polymerization. UV–visible, FT‐IR, XRD, FE‐SEM, DSC, and TGA were employed to examine their structure, morphology, and thermal properties. The broadening and intensification of UV absorption, as well as the shift in IR peaks of PMMA with the addition of CuO, confirm their interactions. The reduction in optical bandgap values with the reinforcement of nanofillers confirms the existence of intermediate energy bands in nanocomposites. XRD indicated that polymerization with CuO reduced the amorphous nature of PMMA. The FE‐SEM image revealed that the dispersion of CuO altered the nonporous, rough surface of PMMA into a homogeneous shape. The reinforcement of CuO enhanced the thermal stability and glass transition temperature of PMMA. The mechanical strength, modulus, impact strength, and rigidity of PMMA were significantly improved through in‐situ polymerization. The electrical property analysis revealed that the AC conductivity increased with frequency, temperature, and filler content. The reduction in activation energy of AC conductivity with temperature points toward their semiconducting nature. PMMA/CuO nanocomposites with higher tensile strength, lower bandgap energy, higher conductivity, and thermal properties can be used to make flexible optoelectronic devices. Highlights: A series of PMMA/CuO nanocomposites were synthesized and characterized.Enhanced optical property, thermal stability, and glass transition temperature.Possess excellent dielectric constant and AC conductivity.Mechanical strength and impact resistance of PMMA were greatly enhanced.A promising material for flexible optoelectronic and power storage applications. [ABSTRACT FROM AUTHOR]

The influence of surface modification and some processing parameters on the palygorskite (Pal) dispersion and the mechanical, thermal and rheological properties of the resulting Nylon 6 nanocomposites was investigated. Natural Pal was surface modified with hexadecyl tributyl phosphonium and 3‐aminopropyl trimethoxysilane to produce organoclays with different surface energy values. Nylon 6/Pal nanocomposites were produced by twin screw extrusion and then injection molded, Pal loading was 2 wt. % in all the cases. A screw configuration was designed to impose different level of shear stresses to the nanocomposites during processing, and nanocomposites were extruded at two different screw speeds. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that Pal was dispersed differently depending mainly on the degree of shear stress and surface modification of Pal. The best tensile mechanical properties were achieved with Pal exhibiting the lowest surface energy value dispersed with the screw having high shear configuration. The fatigue life of nylon 6 improved with addition of Pal. The experimental results give some guidelines for producing Nylon 6/Pal nanocomposites with improved properties. [ABSTRACT FROM AUTHOR]

Poly(ethylene furanoate) (PEF)-based nanocomposites were fabricated with silver (Ag) and titanium dioxide (TiO2) nanoparticles by the in-situ polymerization method. The importance of this research work is to extend the usage of PEF-based nanocomposites with improved material properties. The PEF-Ag and PEF-TiO2 nanocomposites showed a significant improvement in color concentration, as determined by the color colorimeter. Scanning electron microscopy (SEM) photographs revealed the appearance of small aggregates on the surface of nanocomposites. According to crystallinity investigations, neat PEF and nanocomposites exhibit crystalline fraction between 0–6%, whereas annealed samples showed a degree of crystallinity value above 25%. Combining the structural and molecular dynamics observations from broadband dielectric spectroscopy (BDS) measurements found strong interactions between polymer chains and nanoparticles. Contact angle results exhibited a decrease in the wetting angle of nanocomposites compared to neat PEF. Finally, antimicrobial studies have been conducted, reporting a significant rise in inhibition of over 15% for both nanocomposite films against gram-positive and gram-negative bacteria. From the overall results, the synthesized PEF-based nanocomposites with enhanced thermal and antimicrobial properties may be optimized and utilized for the secondary packaging (unintended food-contact) materials. [ABSTRACT FROM AUTHOR]

The scope of the work is to develop in-organic–organic hybrid epoxy nanocomposites using a combination of DGEBA (CY 230) epoxy resin and areca fibre (Af) mixture in the ratio of 70:30, respectively. The mixture was reinforced with varying weight percentages (1 and 2 wt%) of surface-modified nanozinc oxide (M-nZnO) and cured with triethylene-tetra-amine (HY951) at room temperature. 3-aminopropyltriethoxysilane was used as a coupling agent to introduce amine groups on the surface of ZnO and its structure was confirmed by FT-IR. The thermal stability and mechanical properties of in-organic–organic hybrid epoxy nanocomposites having different weight percentages of M-nZnO are investigated by thermogravimetric analysis. Their surface morphology of in-organic–organic hybrid epoxy nanocomposites was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The introduction of M-nZnO improved the mechanical and thermal properties of the in-organic–organic hybrid epoxy nanocomposites. The mechanical characteristics and thermal stability analyses yielded the best results with a 2 wt% addition of M-nZnO nanoparticles. The study's findings clearly suggest that 2 wt% M-nZnO with Af/DGEBA epoxy resin can be used in a wide range of high-performance applications. Interestingly, the Af/DGEBA/M-nZnO epoxy nanocomposites displayed an excellent antibacterial action against high concentrations of Gram-negative bacteria like Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

Shape memory polymers are remarkable materials renowned for their distinctive ability to fix and recover their original shape in response to specific stimuli. However, the lower shape fixity (SF) of conventional thermally triggered shape memory polyurethane (SMPU) has limited its broad application potential. This study investigates the transformative influence of graphene oxide (GO) nanofillers when incorporated into a linear diisocyanate‐based mixing segment SMPU (SMPU‐GO). The lower SF issue of SMPU is ingeniously addressed by leveraging the interactive properties of GO with the 4,4′‐methylene bis‐phenyl diisocyanate hard segment and the introduction of additional physical cross‐links via hexamethylene diisocyanate mixing segment. At 1 wt.% GO incorporation, the modulus increased by 178%, an 8% increase in tensile strength, while the elasticity was maintained. Excellent improvement in SF and shape recovery (SR) was attained at 1 wt.% GO incorporated SMPU, and the SMPU nanocomposite showed the highest SF (65%) and SR (100%) at 70°C temperature and 50% strain. [ABSTRACT FROM AUTHOR]

Polybutylene terephthalate (PBT) nanocomposites loaded with two different types of organoclays are fabricated using the melt mixing technique in a twin-screw extruder. Quaternary ammonium salts with dimethyl, benzyl, hydrogenated tallow, and dimethyl, dehydrogenated tailed modified organoclays are blended with PBT matrix at the compositions of 1%, 3%, 5%, and 10% weight ratios. Test samples are shaped using a lab-scale injection molding device. Mechanical, thermo-mechanical, thermal stability, melt flow, structural, and morphological behaviors of the nanocomposite samples are investigated by performing tensile, impact, and shore hardness tests, dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA), melt flow rate measurements, X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM) methods, respectively. According to the findings, NC 130 clay gave better results than NC 140 in terms of tensile, hardness, and melt flow behaviors, whereas NC 140 showed higher performances as impact resistance, thermo-mechanical, and density, since the reduction in density and weight lowering are highly required for mainly transportation sector, and thermal properties were considered. [ABSTRACT FROM AUTHOR]

In this work, we have synthesized the zinc‐aluminum layered double hydroxide (ZnAl LDH) nanostructures using cost‐effective hydrothermal technique. The ZnAl LDH and graphene‐based poly(vinyl alcohol) (PVA) nanocomposites are fabricated. The crystal structure, morphology, thermal, and dielectric properties of pristine PVA and ZnAl LDH and graphene‐based PVA nanocomposites films were investigated using X‐ray diffraction, HR‐transmission electron microscopy, thermo gravimetric analysis, and impedance analyzer. HRTEM analysis reveals the hexagonal nanoplates shape‐like morphology of Zn‐Al layered double hydroxides with an average thickness of 40–50 nm and size of 400–600 nm. High thermal stability was observed from ZnAl LDH and graphene‐reinforced nanocomposite. Enhanced thermal stability of 250°C and low weight loss was observed from ZnAl LDH reinforced PVA‐based nanocomposites compared to pristine PVA. Zn‐Al LDH nanoplates‐graphene‐PVA based nanocomposites showed ultra‐high dielectric constant (ɛ′) of 794 as compared to the ZnAl LDH‐PVA nanocomposites (ɛ′ ~ 334) and pristine PVA sample (ɛ′ ~ 35). Low dielectric loss of 0.27, 0.18, 0.38 was observed for pristine PVA, ZnAl‐LDH‐PVA and ZnAl‐LDH‐graphene‐PVA nanocomposites. The large enhancement of the dielectric constant and thermal stability were discussed in terms of improved crystallinity, interfacial polarization and formation of nanodipoles in the matrix. This study reveals a significant role of LDH‐graphene‐based hybrid nanocomposites in optoelectronics, energy storage, sensors, energy conversion and thermally stable devices. Highlights: Growth of highly crystalline zinc‐aluminum layered double hydroxide nanostructures.Improved thermal stability for Zn‐Al LDH‐graphene‐PVA nanocomposites.High thermal stability from ZnAl LDH‐based PVA nanocomposites.Ultra‐high dielectric constant of 794 is observed from Zn‐Al LDH nanoplates‐graphene‐nanocomposites. [ABSTRACT FROM AUTHOR]

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]

Electrically conductive nanocomposites based on polypropylene (PP) were prepared using carbon black (CB) nanoparticles via melt blending in the presence of glycerol and castor oil as hydroxyl functional dispersing aids and maleic anhydride–grafted polypropylene (MAgPP) as a compatibilizer. Initially, electrical conductivity of PP/CB nanocomposites with different dosages of both CB nanoparticles and dispersing aids were investigated through electrical analysis. Results indicated that castor oil had no beneficial effects on electrical conductivity. However, the efficiency of 3 wt% loading of glycerol was verified through measurements of electrical, rheological, thermal and mechanical properties as well as by morphological studies. The volume electrical conductivity value of PP nanocomposites containing 12 wt% CB significantly enhanced to 1.2 × 10−4 S/cm by adding 3 wt% glycerol in compared with nanocomposite without glycerol with the volume conductivity value of 1.8 × 10−6 S/cm. Incorporation of optimum amount of glycerol favoured the dispersion of nanofiller in the matrix which was confirmed by scanning electron microscopy observations, leading to higher conductivity due to better formation of conductive pathways within the matrix. Additionally, at the same concentration of CB nanofiller, samples treated with 3 wt% glycerol showed higher melting temperatures, storage modulus (G ˊ), complex viscosity, tensile modulus and elongation at break. These findings indicate that adding an optimum amount of an efficient hydroxyl functional component like glycerol into PP/CB nanocomposite can be a promising way to enhance the electrically conductive performance while other properties could be maintained well or even improved. [ABSTRACT FROM AUTHOR]

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Natural resource-driven approaches to bioengineering plastics are being developed to compete in the automobiles, power, and other sectors. Polytrimethylene terephthalate (PTT) is a particular of them, and it was chosen for the current investigation to build an advanced nanocomposite material. Using a twin-screw micro compounder, injection moulded PTT/Graphene-Oxide (GO)/Carboxyl functionalized Multiwall Carbon nanotube (f-MWCNT) hybrid nanocomposites were prepared. The impact of GO and f-MWCNT reinforcement on the composite's thermal and mechanical characteristics of hybrid nanocomposites was examined. GO was synthesized from the graphite powder by modified Hummer's method and MWCNTs were functionalized using the concentrated sulfuric acid (H2SO4) and nitric acid (HNO3) with a volume ratio of 3:1 in an ultrasonic bath at room temperature. In all formulations, the investigation was done at a constant filler amount of 2 wt%. To understand the chemical interaction between PTT and nanofiller, Raman spectroscopy was used and to examine the state of dispersion, scanning electron microscopy (SEM) was systematically analysed. In comparison to pristine PTT, the water absorption, tensile strength, flexural strength and impact strength of hybrid nanocomposites were improved marginally. It was also observed that GO has more prominent in increasing the mechanical properties of the hybrid and f-MWCNT in thermal properties. The 3-D geometrical bridge between GO (2-D) and f-MWCNT (1-D) made the hybrid more dispersible and effective for different applications. [ABSTRACT FROM AUTHOR]

The present study reports on an environment‐friendly and economically viable method of synthesizing graphene oxide (GO) using agricultural waste, specifically oak (Quercus ilex) fruit. The agricultural waste‐derived GO (AGO) is further used as a reinforcing filler in the fabrication of poly(vinyl alcohol) (PVA) polymer nanocomposites by employing a solution‐mixing process. A series of characterization methods have been used to assess the interactions between AGO and PVA, including, Raman spectroscopy, FT‐IR, field emission scanning electron microscopy (FESEM), and energy‐dispersive x‐ray (EDX). The thermal and structural properties have been studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)analysis, and a universal testing machine (UTM). The strong H‐bonding interaction between the PVA interface and AGO considerably enhanced interfacial dispersion and adhesion. As a result, the addition of 5 wt% AGO to the PVA polymers significantly improved their mechanical and thermal properties, including tensile strength which rose by 117%, melting temperature (Tm) by 7.02°C, and crystallization temperature (Tc) by 9.06°C. The thermal decomposition temperatures such as T5%, T10% and T50% were increased by 53.68°C, 68.49°C, and 57.37°C, respectively. The results show that a small loading of nanofillers causes substantial increases in the thermal and mechanical properties of PVA, thus making it a promising material for structural applications. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) generally does not have high resistance to wear and are characterised by poor thermal stability when exposed to long working condition. To address these shortcomings, this study used hybrid graphene nanoplatelets (GN) and titanium nitride (TiN) nanoparticles to significantly enhance the wear resistance and thermal stability of UHMWPE. The nanocomposites were prepared by solvent mixing and hot compression process. Scanning electron microscope showed uniform dispersion of the nanoparticles in the UHMWPE matrix. The developed UHMWPE showed improved wear resistance and thermal stability relative to the pure UHMWPE. For instance, the wear rate reduced from 6.7 × 10−3 mm3 N−1 m−1 and 3.67 × 10−2 mm3 N−1 m−1 for pure UHMWPE to 2.687 × 10−5 mm3 N−1 m−1 and 1.34 × 7 × 10−4 mm3 N−1 m−1 for UHMWPE–2 wt% GN–10 wt% TiN at applied loads of 10 N and 20 N respectively. This is about 100 % increment in wear resistance at the respective applied loads compared to the pure UHMWPE. The thermal stability of the fabricated nanocomposites was studied using the thermogravimetric analyser (TGA). The addition of nanoparticles significantly reduced the thermal decomposition of UHMWPE matrix. The enhanced properties of the UHMWPE–GN–TiN nanocomposites may be attributed to the network structures formed from the dispersion of the GN and TiN nanoparticles in the UHMWPE matrix with promoted molecular chains interlocking. [ABSTRACT FROM AUTHOR]

Nowadays, biodegradable polymers have gained more attention due to environmental concerns and several inherent properties. However, poor mechanical and thermal properties limit their use for various applications. The nanocomposite is one of the techniques to improve its mechanical and thermal properties. Hence, this technique may be employed to improve its desired properties. This work reports the synthesis and characterization of biodegradable polylactic acid (PLA) nanocomposites. PLA was synthesized by the ring-opening polymerization of lactic acid, magnesium phosphate (MgP), and calcium phosphate (CaP) nanoparticles were added into the PLA matrix. The nanocomposites were prepared by ultrasonic vibration-assisted melt mixing and vacuum casting techniques. The prepared PLA nanocomposites were further characterized to determine their tensile strength and thermal conductivity. The experiments were designed by employing the central composites design to study the effect of MgP and CaP nanoparticle concentration on the mechanical and thermal properties of PLA nanocomposites. The result indicates that the highest tensile strength was achieved for 10 wt% CaP and 2.35 wt% concentration whereas maximum thermal conductivity of PLA nanocomposites was obtained for 20 wt% CaP and 2.35 wt% concentration. [ABSTRACT FROM AUTHOR]

This study explores the impact of different levels of halloysite nanotubes (HNT) and d-isomer on the non-isothermal crystallization behavior of the polylactic acid (PLA). The processing conditions, thermal flow, molecular orientation and the presence of nanofillers can affect the crystallinity and properties of PLA. In this work, PLA-based nanocomposite filaments were produced and their crystallization kinetics was studied. The data obtained through experiments, using differential scanning calorimetry at various cooling rates, were analyzed employing the Jeziorny and Mo models. And the activation energy of crystallization was determined by the Friedman method. The results showed that the growth of PLA crystals is three-dimensional, the HNT can accelerate the crystallization process, and crystallization occurs at higher temperatures in the presence of flow. The activation energy increased with addiction of more HNT in the nanocomposite. The study also found that the d-isomer has a more significant influence on the crystallization of PLA than HNT, which can inhibit crystal formation in some cases. These findings provide insights into the factors that can influence the properties of PLA nanocomposites and how they can be optimized. [ABSTRACT FROM AUTHOR]

This paper presents the investigating results of the effect of different nanofillers like unmodified and modified halloysite nanotubes (HNT), nanosilica, and nano-titanium on the mechanical and thermal properties of polyetherimide (PEI)/silicone rubber-based nanocomposites. The PEI/silicone rubber nanocomposites reinforced with different nanofillers at 3 phr were prepared with the aid of a co-rotating twin-screw extruder. The developed nanocomposites were compared by various mechanical properties, thermal properties, and dynamic mechanical analyses. Morphological properties have been visualized by scanning electron microscope. The results obtained depict that the tensile strength, tensile modulus, storage modulus, and glass transition temperature have significantly increased with the incorporation of modified HNT at 3 phr loading due to the interfacial and inter-tubular interactions between HNT and polymer matrices. The enhancement in glass transition temperature may be because of the restricted movement of the polymer chains by the nanofillers, and the formation of HNT zig-zag structures is the main reason for the improvement of various properties. The bridging effect of modified nanosilica at the blend interface may also be responsible for the enhancement of elongation at break and impact strength which is higher than other nanofillers. [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]

Polymer nanocomposites have been of great interest to packaging, energy, molding, and transportation industries due to several favorable properties including a higher resistance to stress and cracking even under flexed conditions, and also a chemical resistance to water, acids, and alkalis. The current work disseminates the studies on the mechanical and thermal properties of the polypropylene HHR102 polymer reinforced with nano dispersoids of silicon dioxide at varied weight fractions. The nanocomposites, fabricated via melt processing followed by injection molding, were tested for tensile strength, % elongation, tensile modulus, and impact toughness. Further, the samples were also subjected to dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) to determine the dynamic storage modulus and thermal stability. The addition of nano-silica in polypropylene HHR102 resulted in enhanced ductility and well-balanced tensile modulus; however, the tensile strength and impact toughness were found to be decreased. On the other hand, the storage modulus was significantly increased for all nano-silica (NS)-containing polypropylene HHR102 matrices. With the increased nano-silica content, the storage modulus was optimal. Further, with the lower weight loss of 30% and 50%, the thermal stability of the increased silica content PP nanocomposites was much affected. However, it improved at a weight loss of 30% for the lower silica content PP nanocomposite (PP-1%NS). The imbibition was found to increase with the increase in NS. The increase in imbibition is attributed to the micro-voids generated during ageing. These micro-voids act as channels for water absorption. Further, the degree of crystallinity of the nanocomposites was decreased as a result of inhibition by the nano-particles on the regular packing of polymer molecules. The structure–property correlations were explicated based on the achieved mechanical properties. [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]

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 main operational characteristics of polyamide-6-montmorillonite (PA6/MMT) nanocomposites, which determine their fields of application, mainly depend on the crystal structure and crystallinity of the polymer. Therefore, the study of the crystalline behavior of PA6 in such nanocomposites is of considerable scientific and practical importance. In this work, the structure, crystalline, and thermal properties of nanocomposites based on PA6 and modified MMT prepared in a formic acid solution were investigated using the methods of differential scanning calorimetry (DSC) and X-ray Diffraction (XRD). It was established that during the manufacture of PA6/MMT nanocomposites in a solution, the dominant crystal structures are the thermodynamically stable a structures of PA6. The crystallinity degree of PA6 in nanocomposites is about 1.5 times higher than that of the original PA6. It is shown that after additional thermomechanical treatment of nanocomposites on a capillary viscometer at 230 °? and a load of 5 kg, the uniformity of the distribution of exfoliated MMT in the polymer matrix increases, as a result of which the crystalline structure of PA6 changes and its glass transition and melting temperatures increase. These changes in the PA6 structure also have a significant impact on the melt flow index and the softening temperature of nanocomposites. [ABSTRACT FROM AUTHOR]

In the current study, novel polyvinyl alcohol‐based films with polyethylene glycol as a plasticizer and aluminum nitride (AlN) nanoparticles (0.1–0.5 wt%) as a reinforcing agent were fabricated by facile solution casting route. The prepared composite films were characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X‐ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). Additionally, morphology, water contact angle, and optical and mechanical properties were evaluated. FTIR analysis disclosed that the backbone structure of PVA/PEG was not affected by nanofiller loading, and the type of interaction between the PVA/PEG matrix and AlN nanoparticles was physical; furthermore, it was observed that as AlN nanoparticle loading increased in the composite films, water contact angles also increased. Interestingly, the nanocomposite films showed >90% blocking of UV light (200–400 nm) and very high flexibility with an elongation at break of approximately 190%. In comparison with PVA/PEG, the composite films developed by reinforcing 0.3 wt% of AlN (PVA/PEG/0.3AlN) exhibited a 17.94°C increment in thermal degradation temperature and a 7.36°C increment in glass transition temperature, along with a 1.2‐fold increment in tensile strength. Highlights: Fabrication of polyvinyl alcohol/polyethylene glycol/aluminum nitride films.The composite films showed >90% blocking of UV light.Thermal stability maximally enhanced at 0.3 wt% loading of aluminum nitride.The composite films demonstrated very high flexibility. [ABSTRACT FROM AUTHOR]

The manufacture of flexible devices is of immense interest due to their eco-friendliness, economic prospects and wide range of applications in biocompatible devices. Therefore, this paper reports the characterization and properties of chlorinated natural rubber (Cl-NR)/polyindole (PIN) blend with different contents of nickel oxide (NiO) nanoparticles. The formation of blend nanocomposites was analysed by FT-IR, UV spectroscopy, XRD, FE-SEM, DSC and TGA. The FT-IR and UV spectra proved the effective interfacial interaction between nanoparticles and the blend matrix, with a shift in UV peak intensity with the attachment of NiO at 433 cm−1. The XRD pattern revealed the regular arrangement of the blend matrix due to the presence of nanofiller, resulting in the semicrystalline structure of the composite system. The SEM micrographs revealed a homogeneous distribution of NiO in the blend matrix. The increased degradation temperature in the TGA demonstrated the enhanced thermal stability of the NiO-filled Cl-NR/PIN blend. DSC results showed that the glass transition temperature of the composite increased with NiO content in the blend matrix. The dielectric properties and AC electrical conductivity increased significantly with increasing temperatures, as well as with the addition of nanoparticles up to 5 mass % loading. The inclusion of NiO improved the tensile strength and hardness while reducing the elongation-at-break of nanocomposites. The blend nanocomposite with enhanced thermal stability, glass transition temperature, tensile strength, AC conductivity and dielectric properties enables them to be used in highly flexible electronic applications where traditional elastomeric materials fall short. [ABSTRACT FROM AUTHOR]

The work was aimed to study the influence of multi-walled carbon nanotubes (MWCNT) on the thermostructural properties of aluminum matrix in a wide temperature range from 30 to 600 °C. To achieve this aim, a nanomaterial with a composition of Al + 1.5% MWCNT was elaborated by sintering and rolling from aluminum and MWCNT powders. This material has to combine the ductility and lightness of aluminum with the toughness and thermal properties of MWCNT, and it can replace classical metal materials. The mechanical and structural properties of Al + 1.5% MWCNT material were studied using different techniques: differential scanning calorimetry, X-ray diffraction, thermogravimetry, Raman spectroscopy, and dilatometry. The reaction between an Al matrix and nanotubes leads to the formation of the carbides and some carbon dissolution in the matrix's crystal network. These reactions also lead to a refinement of the matrix grain and a more homogeneous distribution of the residual MWCNT. These phenomena significantly influence the structure of the matrix as well as the mass and dilatometric stability of the material. Reduction of the dilatometric coefficients of the composite material was observed in the entire temperature range of 30–600 °C, especially a significant reduction was measured for temperatures higher than 200 °C. The results obtained by differential calorimetry showed a noticeable decrease in the calorific capacity of the nanocomposite compared to that of the pure material, especially for temperatures higher than 200 °C. The essential role of anisotropy in determining the thermal expansion characteristics of the nanocomposite was revealed. [ABSTRACT FROM AUTHOR]

Herein, biopolymer nanocomposite films were prepared from the blend of two polymers, polyvinyl alcohol (PVA) and cashew gum (CG), incorporated with various concentrations of nanochitosan (nCS) via the green solution casting method. The effects of nCS on the structural, morphological, mechanical, thermal and electrical/dielectric characteristics of the PVA/CG blend have been investigated and discussed. The major absorption peaks of PVA and CG were revealed by the Fourier transform infrared study, and their positions slightly changed with the insertion of nCS. X-ray diffraction results revealed that the crystallinity degree of the nanocomposite samples increased with increasing nCS content. The consistent distribution of chitosan nanofillers in the blend network was visible in the scanning electron microscopy images. Differential scanning calorimetry and thermogravimetric analysis showed that increasing the nanofiller loading into the PVA/CG increased the glass transition temperature and thermal stability. The electrical impedance measurements showed that the nanofiller loading increases the electrical conductivity and dielectric properties. The AC conductivity of PVA/CG/7wt% nCS was 1.46 times higher than the pure blend. The activation energy of electrical conductivity decreases as temperature increases, and the PVA/CG/7wt% nCS sample had the lowest activation energy of conduction (0.3495 eV). The semiconducting behaviour of the blend nanocomposites was explained by the skewed semi-circular arc observed in Nyquist plots. The tensile strength of 5wt% nCS loaded blend was 43.2% higher than the pure PVA/CG blend. These results suggest that this blend nanocomposite films could be a candidate for capacitors and flexible energy storage devices. [ABSTRACT FROM AUTHOR]

In this study, the effects of ball milling (BM) technique and carbon nanotube (CNT) content on the thermal and mechanical properties of hybrid reinforced composites were investigated. The composites were prepared using glass fiber (GF), novolac resin (No), and CNTs with different wt% (1, 2, and, 4). Various milling times were used to optimize the entanglement/agglomeration of CNTs in the polymer matrix and subsequently enhance the final thermal and mechanical properties. Through precise investigations, it was found that the nanocomposite with 2 wt% CNT reinforcement, subjected to 2 h of BM, exhibited remarkable enhancements in key properties. The tensile strength was significantly improved to 45.6 MPa, while the elastic modulus reached 3.419 GPa. Hardness was measured at 96 HRM, and thermal conductivity was enhanced to 0.463 W/mK. Moreover, this sample demonstrated a weight loss that was 43.65% lower compared to the sample reinforced with 1 wt% CNT and subjected to 1 h of BM. Overall, this study highlights the importance of optimizing the milling time and CNT content in the preparation of polymer nanocomposites, and it provides valuable insights for the development of advanced materials with superior performance in various applications. [ABSTRACT FROM AUTHOR]

Polyoxymethylene (POM) nanocomposites were reinforced with 1 phr of synthetic wollastonite nanofibers (SWN) to investigate the effect of the aspect ratio of SWN on the mechanical, thermal and flammability properties. The tensile strength, Young's modulus, and impact strength of POM nanocomposites demonstrated an increasing trend as the aspect ratio of SWN increased. POM nanocomposites incorporated SWN with an aspect ratio of about 20 (POM/SWN‐20) exhibited higher tensile strength (2%), Young's modulus (3%) and impact strength (50%) as compared to that of about 5 (POM/SWN‐5). A higher aspect ratio of SWN also contributed to the better thermal stability of POM nanocomposites, in which the initial degradation temperature of POM/SWN‐20 was about 6°C higher than POM/SWN‐5. Interestingly, SWN that possessed a lower aspect ratio performed better in flame retardancy, as indicated by the increase in the time to ignition and the decrease in the peak heat release rate. This present study demonstrates the relationship between the aspect ratio of filler (SWN) with the polymer matrix (POM), which is crucial in producing nanocomposites that have great potential in automotive applications. [ABSTRACT FROM AUTHOR]

A new melt mixing and in‐situ exfoliation method based on the synergy of multi‐source pulsating flow and phase transition (MSPFPT) was reported. The corresponding device was also developed, and the structure and mixing process of the mixer were introduced in detail. High‐density polyethylene (HDPE)/expanded graphite (EG) composites were prepared via this new mixer, and microstructure and thermal properties of the composites were comprehensively investigated. Morphological analyses demonstrate that MSPFPT method promotes the efficient exfoliation and uniform dispersion of EG. The well‐exfoliated EG layers form more thermal conductive paths in the composites prepared by MSPFPT, increasing thermal conductivity from 0.47 of pure HDPE to 1.16 W/(m·K) with 9 wt.% EG. The crystallinity degree of HDPE is increased by 11.1%. The increment of crystallinity reduces phonon scattering, which further confirms that MSPFPT method can significantly improve the thermal performance. The research provides a practical strategy for fabricating high‐performance composites filled with layered fillers. [ABSTRACT FROM AUTHOR]

This study investigated the relationship between the structure and mechanical properties of polycaprolactone (PCL) nanocomposites reinforced with baghdadite, a newly introduced bioactive agent. The baghdadite nanoparticles were synthesised using the sol–gel method and incorporated into PCL films using the solvent casting technique. The results showed that adding baghdadite to PCL improved the nanocomposites' tensile strength and elastic modulus, consistent with the results obtained from the prediction models of mechanical properties. The tensile strength increased from 16 to 21 MPa, and the elastic modulus enhanced from 149 to 194 MPa with fillers compared to test specimens without fillers. The thermal properties of the nanocomposites were also improved, with the degradation temperature increasing from 388 °C to 402 °C when 10% baghdadite was added to PCL. Furthermore, it was found that the nanocomposites containing baghdadite showed an apatite-like layer on their surfaces when exposed to simulated body solution (SBF) for 28 days, especially in the film containing 20% nanoparticles (PB20), which exhibited higher apatite density. The addition of baghdadite nanoparticles into pure PCL also improved the viability of MG63 cells, increasing the viability percentage on day five from 103 in PCL to 136 in PB20. Additionally, PB20 showed a favourable degradation rate in PBS solution, increasing mass loss from 2.63 to 4.08 per cent over four weeks. Overall, this study provides valuable insights into the structure–property relationships of biodegradable-bioactive nanocomposites, particularly those reinforced with new bioactive agents. [ABSTRACT FROM AUTHOR]

Agave Tequilana Weber (ATW) is the base ingredient for preparing tequila liquor; tequila production yields tons of waste rich in cellulose representing environmental issues. Cellulose nanocrystals (CNC), the crystalline regions extracted from cellulose microcrystals, were obtained from the waste of ATW as an attractive alternative to reinforce polymeric materials. CNC were grafted with (poly (2-ethyl hexyl acrylate) to improve compatibility with hydrophobic polymers. The CNC pristine (CNCP) and grafted (CNCG) were dispersed in PLA (0.5, 1 and 2 wt.%), employing several melt processing stages. CNC distribution within PLA matrix was followed using SEM and TEM. Also, thermal properties were characterized through differential scanning calorimetry and thermogravimetric analysis. Thermal stability of nanocomposites increased with CNC, CNCG nanocomposites showed better results (Td ~ 370 °C) than CNCP nanocomposites (Td ~ 366 °C). The degree of crystallinity showed for CNCG (25.1%) was higher than for CNCP (21.1%) nanocomposites. The tensile properties were improved with CNCP (0.44 MPa) and CNCG (2.11 MPa) content. The CNC increased the shear properties of PLA melt and exhibited a strain-hardening behavior during elongational rheology test. The CNC and CNCG are an interesting alternative to modify the melt rheological behavior and the mechanical behavior in the solid-state of low melt strength polymers, which could be thermally degraded during processing. Composites could be used to produce films for the food industry through blow-extrusion processing. [ABSTRACT FROM AUTHOR]

In this study, solid styrene‐butadiene rubber (SBR) compound nanocomposites containing hybrid nanoclay–graphite nanofillers with different weight fractions were fabricated through a two‐roll mill process, and surface response methodology (SRM) using Minitab software was employed for designing experiments and developing good relationships between independent factors and responses. The impact of nanoclay, graphite, and their hybrids on the mechanical, aging, and thermal properties of filled SBR was studied. Compared with neat SBR, the SBR containing 10 phr nanoclay and 15 phr graphite (SBR/10/15) showed the highest tensile strength and tensile modulus with 55 and 47% rise, respectively. Also, A maximum increase in hardness was observed for SBR/5/30 by 42%, and it was revealed that nanofillers reduced the elongation at break. Additionally, despite reducing the mechanical properties of neat SBR, hybrid nanocomposites maintained their properties during aging so that the SBR/10/15 presented maximum aging resistance. The SBR/10/15 presented maximum aging resistance as it significantly retained its mechanical properties during the test. Moreover, thermal stability was investigated using thermogravimetric analysis (TGA). The results demonstrated that the hybrid nanofillers improved the thermal stability of SBR. [ABSTRACT FROM AUTHOR]