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While improving the thermal conductivity of composites, single‐size carbon nanotubes (CNT) often degrade their mechanical properties due to the agglomerates. To overcome this limitation, this study reported thermoplastic resin matrix composites synergistically reinforced with small, medium, and large‐size carbon nanotubes (S‐CNT, M‐CNT, and L‐CNT). Using the thermal conductivity (λ) and mechanical properties (flexural strength [F], compressive strength [C] and tensile strength [T]) as the response values, we conducted 21 sets of mixing design experiments and developed the associated quadratic term models. Further multi‐objective optimization was carried out for the above response values. Optimized multiscale CNT synergistically modified composites (S‐CNT, M‐CNT, and L‐CNT contents of 1.25, 7.02, and 2.56 wt%) exhibited a λ value of 1.168 W/mK, which was 121% higher than that of pure composite and also superior to the same content of S‐CNT‐ (1.031 W/mK), M‐CNT‐ (1.016 W/mK), and L‐CNT‐modified composites (0.983 W/mK). Additionally, the optimized composite demonstrated excellent mechanical properties (F = 1482 MPa, C = 848 MPa, and T = 1759 MPa), which were 13%, 11%, and 13% higher than those of the pure composites, respectively, and also surpassed those of the S‐CNT‐, M‐CNT‐and L‐CNT‐modified composites. Highlights: Using three different scales of carbon nanotubes modified CF/PPBESK composites.Polynomial modeling of composite's thermal conductivity and mechanical properties.Synergistic interactions between carbon nanotubes to improve the composite's thermal conductivity and mechanical properties. [ABSTRACT FROM AUTHOR]

Liner materials have extensive applications in automobile industry, packaging, and aeronautics. One of the specific uses of such materials is in thermal barrier, coating rockets, missile, and other systems used in space and defense. Each liner material exhibits different properties according to their chemical structure and composition. In this study, accelerated thermal aging of the liner material, silicone‐hollow glass microsphere composite (SHGC) has been studied along with the determination of its life span. The effect of such aging on the thermal properties of SHGC has been studied using thermogravimetry. Activation energy of the process has been determined to be in the range of 45–55 KJmol−1. The results have been compared with already reported silicon polymers. Shelf‐life of SHGC composite has also been determined using Arrhenius model. Stochastic model has been applied to determine the lower and upper limits of shelf‐life. Shelf‐life of SHGC is found to be 24 years with 28 and 18 years of upper and lower error limits. [ABSTRACT FROM AUTHOR]

In this study, graphene nanoplatelets were applied to polyester fabrics using the knife‐coating method at different concentrations (50, 100, and 150 g/kg). SEM, DSC, and TGA/DTG analyses were performed. The influence of graphene coating on hydrophobicity and surface roughness was examined by water contact angle (WCA) measurement and root mean square roughness, respectively. Abrasion resistance and tear strength tests were also performed. The effect of graphene used as a filler on the flammability of polyester fabric was evaluated for the first time according to the BS 5852 standard. No significant weight loss (only in the range of 0.4%–1.5%) was observed in the graphene‐coated samples even after 100,000 cycles. While the WCA value was 0 for the uncoated fabric, the blind coating and maximum graphene‐coated sample measured 86° and 95°, respectively. The coating process reduced the roughness of the base fabric, and the decrease continued with the increasing graphene ratio. The tear strength values that were 45.5 N in the warp and 53.6 N in the weft direction in the blind coating, increased to 52.2 and 59.1 N, respectively, at the maximum graphene concentration. Graphene coating enhanced thermal stability, increased hydrophobicity, and improved flame retardancy in the test using a smoldering cigarette. [ABSTRACT FROM AUTHOR]

First-principles computations are used to investigate the structural, stability, mechanical, optical, thermal, and electronic characteristics of perovskite material. A novel RbBa 2 Ti 3 O 10 perovskite material is studied by using the generalized gradient approximation (GGA) suggested by Perdew, Burke, and Ernzerhof (PBE) approach in the CASTEP code. According to findings, the compound structure is tetragonal in nature with a space group of 123 (p4/mmm), a lattice parameter, and a volume. RbBa 2 Ti 3 O 10 exhibits indirect bandgap semiconductor behavior, according to its electronic characteristics. The Kramer-Kroning (KK) relations are used for determining optical properties to observe light-matter interaction. Perovskites' mechanical attributes, including their ductility, compressibility, elastic anisotropy, modulus, and mechanical index, were assessed and assigned. The thermal properties of the compound are examined, including its density, minimum thermal conductivity, melting temperature, and Debye temperature. Our investigation shows that RbBa 2 Ti 3 O 10 has potential use in photocatalytic applications. • The compound structure is tetragonal with a space group of 123 (p4/mmm). • RbBa 2 Ti 3 O 10 exhibits indirect bandgap (1.66 eV) semiconductor behavior. • Perovskites' mechanical attributes, like compressibility, anisotropy, modulus, and mechanical index, were assessed. • The thermal properties are examined, including its minimum thermal conductivity, melting temperature, and Debye temperature. • RbBa 2 Ti 3 O 10 has potential use in photocatalytic applications to separate water for H 2 and O 2 production. [ABSTRACT FROM AUTHOR]

Difunctional glycidyl azide polymer (GAP) is an energetic binder promising for propellant formulations. The multifunctional fluorine‐containing GAP has been synthesized to enhance its mechanical properties. This work outlined multifunctional GAP partially grafted with 1,2,3‐triazole‐5‐(α‐hydroxyl)‐fluorinated polyether (GAP‐g‐3F) synthesized by thermal and catalyst‐free azide‐alkyne cycloaddition reaction, in which the azide groups were from GAP and electron‐deficient alkynes from β‐propargyl‐α‐hydroxyl poly (tri‐fluoropropane glycidyl ether) (PHP3F). PHP3F was synthesized via the typical cationic ring‐opening polymerization of 2‐((2,2,2‐trifluoroethoxy) methyl) oxirane and propargyl alcohol as the initiator. The chemical structures, molecular weight, and thermal properties were characterized by FTIR, NMR, GPC, DSC, and TGA, respectively. HNMR results showed that 8 % of total azide groups in GAP were grafted. GAP‐g‐3F had a slightly higher glass transition temperature than that of GAP. The results of TGA showed that GAP‐g‐3F had suitable thermal decomposition resistance up to 200 °C. The thermal properties, mechanical properties, cross‐linking network structures, and microstructures of the polyurethane networks cured with hexamethylene diisocyanate trimer as a crosslinking agent were determined and compared by TGA, universal tensile test, swelling measurement, and SEM, respectively. The initial decomposition temperature of GAP‐g‐3F‐based polyurethane networks (GAP‐g‐3F‐PU) was around 220 °C, thus meeting the requirements for propellants. In addition, GAP‐g‐3F‐PU exhibited superior mechanical properties, showing an almost twelvefold increase in tensile strength to 16.9 MPa compared with difunctional GAP‐PU with 1.4 MPa tensile strength. The results of the swelling measurement revealed that the GAP‐g‐3F‐PU sample showed a higher crosslinking density in comparison to the GAP‐PU sample. SEM results indicated that the multifunctional fluorine‐containing GAP could enhance compatibility between the soft and hard segments of polyurethanes, leading to a decrease in their separation degree. This finding showed that the synthesis of a multifunctional GAP partially grafted with fluorinated polyether via a triazole ring may be a promising solution to decrease the separation degree increase of PUs, thereby improving the mechanical properties. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) recyclates face limitations in their use due to lower qualities compared with virgin PP, resulting from contaminations and the mixing of different PP grades. In particular, their high melt flow rate (MFR) hinders their suitability for applications requiring low MFR, such as pipes. This study investigates the feasibility of producing low MFR PP recyclates from packaging waste. For this purpose, recyclates were produced exclusively from manually sorted extrusion blow molding grades and compared with a recyclate derived from a conventional PP waste stream. Different washing temperatures and recyclate production processes were used to study their effects on the properties of the recyclates. The main objective was to determine the lowest achievable MFR and the rheological, mechanical, and thermal properties of the recyclates from improved sorting. The results are intended to serve as reference points for the evaluation of future automatic sorting trials. The enhanced sorting resulted in an 80% reduction in the MFR and improved ductility, thereby extending the potential applications of the recyclate. The different washing and production processes did not have a significant effect on the investigated properties, except for a slight decrease in the MFR with hot washing and the omission of the pelletizing step. [ABSTRACT FROM AUTHOR]

Biochar, a carbon‐rich biomass material has emerged as promising reinforcement and offers versatile applications and potential benefits in various fields, especially in fused deposition modeling (FDM). This study focuses on the development and characterization of groundnut shell‐derived biocarbon (GNSC) reinforced polylactic acid (PLA) filaments for FDM. The GNSC was synthesized through pyrolysis using a tubular furnace at temperatures 700, 800, and 900°C. Synthesized carbon was characterized using Raman spectroscopy, XRD, and SEM analysis. The results showed that the synthesized carbon particles were graphitic, spherical, and nanosized with an average diameter of 40 nm. The preferred biocarbon material, GNSC800 was selected for its high carbon content (98.25%) observed through EDX analysis. Composite filaments were produced with different GNSC800 loadings of 0.25%, 0.5%, and 0.75% using solvent casting and extrusion techniques. Thermal stability was evaluated using TGA and DSC, which showed improved properties with the addition of biocarbon. The mechanical properties and electrical conductivity were enhanced with the inclusion of biocarbon. The data were also validated using ANOVA and Tukey's test. Filament with the 0.5 wt% loading showed the most favorable thermomechanical properties exhibiting a 39.8% increase in tensile strength and a 17.5% improvement in tensile modulus. [ABSTRACT FROM AUTHOR]

The strength of zirconium diboride ceramics was tested by three different methods, 3‐point flexure, 4‐point flexure, and compression. Nearly full‐density ceramics were obtained by hot pressing commercial ZrB2 powder with the addition of .5 wt.% carbon as a sintering aid. The thermal properties and hardness were studied for ZrB2 milled with ZrB2 and WC media. Based on phase purity and higher thermal conductivity, ZrB2 ceramics prepared from powders milled with ZrB2 media were selected for mechanical property studies. The strength in 3‐point flexure was 546 ± 55 MPa. The flexure strength was 476 ± 41 MPa in 4‐point bending, which was ∼20% higher than the previously reported value of 398 MPa for ZrB2 with similar grain sizes due to higher relative density and lower impurity contents. Compression testing was performed at room temperature, and the strength was 1110 ± 358 MPa. Finally, the fracture toughness of pure ZrB2 ceramics was determined by the chevron‐notched beam method to be 3.6 ± .7 MPa m1/2. The strength and fracture toughness values are higher than those previously published for ZrB2 ceramics and can be attributed to higher density and lower grain size. The strength‐limiting flaw sizes were comparable to the grain size, suggesting that porosity and impurity phases did not play a significant role in the strength of these ceramics. [ABSTRACT FROM AUTHOR]

Highlights The study investigates the impact of cobalt ferrite (CF) concentration on the electrical, thermal, mechanical, magnetic, and electromagnetic interference (EMI) shielding effectiveness (SE) of Epoxy/Graphene/Cobalt ferrite composite samples. This paper presents the novel impact of agglomeration formation using an increased CF concentration, which results in the  enhancement of electrical conductivity and slight decrease in EMI SE after 7% CF loading. The scanning electron micrograph provided a clear evidence for the formation of agglomeration with the increase of CF content. The amount of CF loading in Ep/Gr was varied steadily to achieve electrical percolation. The maximum tensile strength value of 21.6 MPa was observed for sample with 7% CF. The sample with 15% CF exhibited the maximum saturation magnetization of 7.5 emu/gm. TG‐DTA showed thermal degradation of all samples up to 800°C. The maximum shield effectiveness (SE), 16 dB was observed for sample with 7% CF in X band and 22 dB for sample with 10% CF in Ku band frequency range. The composites exhibited great absorption properties compared to reflection in both X band Ku band frequency range. These epoxy‐based composites are useful as cost effective EMI shielding material. Hybrid filler (CF/graphene) addition alters properties of composites Structural, thermal, mechanical, electrical and, magnetic properties of composites reported Agglomeration of nanoparticles effect mechanical and EMI shielding properties. Electrical conductivity improved with filler addition The EMI Shield effectiveness is dominated by absorption loss in both X and Ku band [ABSTRACT FROM AUTHOR]

This study investigates the impact of algae loading on the properties of PBAT/algae bio‐composites produced through a melt extrusion process. The integration of algae as a filler demonstrated a reinforcing effect on the PBAT matrix, leading to an increase in modulus with higher algae loading. Concurrently, the tensile strength and maximum tensile strain of PBAT decreased with an increase in algae content. The thermal stability of PBAT was affected by adding algae, resulting in bio‐composites exhibiting an intermediate behavior compared with their neat precursors. The optimal formulation is achieved with 20 wt.% of algae incorporated into the PBAT matrix. The produced PBAT/algae bio‐composites, demonstrated versatile applications across a wide range of products. [ABSTRACT FROM AUTHOR]

Bast fiber-reinforced polymer composites (BFRPs) are grabbing considerable research attention due to their assertive impact on the environment and excellence in biodegradability. Though BFRPs have excellent ecological performance factors, they also lack in some cases, such as lower mechanical, electrical, and thermal properties, due to the significant moisture absorption, minimal thermal stability, and inherent nature of bast fibers. BFRPs exhibit weaker fiber/matrix interfacial adhesion as compared to synthetic fiber-reinforced polymer composites, resulting in lower mechanical properties. Nowadays, a wide variety of fiber and matrix modification techniques are practiced improving the fiber-matrix interaction, which ultimately improves the mechanical properties. Among the fiber and matrix modification techniques, nanofiller integration is the most promising one. This study reviews the impacts of introducing carbon-based nanofillers, particularly graphene and carbon nanotubes (CNT), in diversified BFRPs. The influence of carbon-based nanofillers on the mechanical, electrical, and thermal behavior of BFRPs and their potential prospects are comprehensively reviewed. The paper concludes with the challenges and difficulties in composite processing, along with the techniques for overcoming them. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) composite serve as widely used filaments in fused deposition modeling (FDM) 3D printing. This study investigates the enhancement of PLA composite's comprehensive mechanical properties and thermal stability through the incorporation of carbon fiber (CF). The influence of FDM process parameters on the mechanical properties of PLA composite is also analyzed. Results show that adding 5 wt.% CF significantly enhances the stiffness and comprehensive mechanical properties of PLA composite. The order of printing factors affecting the tensile strength of the PLA composite product is as follows: printing layer thickness, bottom plate temperature, printing speed, and nozzle temperature. Finally, optimal tensile strength is achieved under specific conditions: 0.1 mm layer thickness, 60 °C bottom plate temperature, 40 mm/s printing speed, and 215 °C nozzle temperature. [ABSTRACT FROM AUTHOR]

To enhance mechanical, adhesive, and thermal properties of Room Temperature Vulcanized (RTV) silicone rubber, a silicon-containing polyurethane/epoxy resin modifier (ESiPU) was developed. A three-phase system of polyurethane/epoxy resin/silicone rubber was prepared through blending, modification, and co-curing. FT-IR and 1H-NMR were employed to characterize the chemical structure of ESiPU. Microscopic analysis revealed improved compatibility between modified epoxy resin and silicone rubber. Mechanical testing showed significant enhancements in tensile strength, elongation at break, and adhesive strength, with RTV-20phr exhibiting increases of 236, 266, and 259%, respectively. Thermogravimetric analysis indicated higher initial decomposition temperature compared to pure RTV. At the same time, the char residue at 800 °C increased to 8.67%. TG-IR analysis demonstrated ESiPU's ability to delay thermal degradation. Contact angle test confirmed improved hydrophobicity. Overall, the developed silicone rubber system exhibits promising mechanical and thermal properties, suggesting potential for aerospace heat protection applications. [ABSTRACT FROM AUTHOR]

Highlights The homogeneous dispersion of multi‐walled carbon nanotubes (MWCNTs) in a polymer matrix significantly affects the overall properties of composites. In this study, MWCNTs/epoxy (EP) composites were prepared using DeoxyriboNucleic acid (DNA) as a dispersant. The MWCNTs were uniformly dispersed in a phenalkamine curing agent and crosslinked with an epoxy resin matrix. The non‐covalent functionalization of DNA‐dispersed MWCNTs was confirmed by characterizing both the pristine and DNA‐modified MWCNTs. Additionally, the dispersion state and stability of MWCNTs in the curing agent solution were evaluated. Tensile strength and single‐lap‐shear (SLS) were employed to assess the mechanical properties of the composites. The results indicated that the DNA‐dispersed MWCNTs composites exhibited superior strength and toughness, with tensile and shear strengths of 46.81 and 19.64 MPa, respectively, at optimal ratios. These values represent increases of 68.38% and 50.96% compared to pure EP. Dynamic mechanical thermal analysis (DMTA) revealed that the energy storage modulus of DNA‐dispersed MWCNTs/EP composites increased to 2722 MPa, a 24.7% enhancement over pure EP. Furthermore, the thermal properties of the composites were thoroughly investigated. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed that the initial decomposition temperature of the DNA‐assisted dispersed composites rose to 330°C. The macromolecular relaxation of the EP materials occurred at higher temperatures, leading to an increased glass transition temperature. DNA was used to disperse MWCNTs in phenalkamine curing agent. MWCNTs/EP composites were made by crosslinking DNA‐dispersed MWCNTs with epoxy resin. DNA‐dispersed MWCNTs boosted tensile and lap shear strength. Thermal properties improved due to DNA‐dispersed MWCNTs, and increased the energy storage modulus of the composite. [ABSTRACT FROM AUTHOR]

Composites are fabricating by reinforcing waste bambara nut shell powder (BNSP) as a bio-filler into an epoxy resin matrix. The composite is fabricated by varying the mass fractions of filler in the range of 5–35 wt%. The effects of bio-filler content on physical, mechanical, and thermal properties are evaluated. The studies reveal that the tensile strength, tensile modulus, flexural strength, and impact strength increased with increasing bio-filler content. The highest mechanical properties of BNSP-loaded epoxy composites are achieved at bio-filler mass content of 15 wt%, whereas hardness increased for 5–35 wt% with peak value at 35 wt%. The water absorption and thickness swelling of the BNSF/epoxy composites increased with increasing bio-filler contents, while the density decreased with an increase in bio-filler content. The TGA results revealed that an increasing bio-filler content decreased thermal stability, whereas the Tg and Tm of the composites increased with increasing bio-filler content. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of fiber surface treatment on various properties of hair fiber reinforced composites. Human hair fiber reinforced modified epoxidized soybean oil based composites were prepared by compression molding technique. Acid treatment of hair fibers was carried out by using three different concentrations of HCl solution (0.25%, 0.75%, and 1%, respectively) in order to achieve improvement in adhesion between the fiber and the matrix. Epoxidized soybean oil was modified using methacrylic acid and methacrylic anhydride to form methacrylic anhydride modified epoxidized soybean oil. Rosin acid derivative (a rigid comonomer) was prepared and used as a crosslinker. Fourier‐transform infrared spectroscopy was carried out to study the interaction among the components of the composites. Various properties, namely, mechanical, thermal, flame resistance, and chemical resistance were checked. Scanning electron microscopy of the fractured surface of the composites was carried out to examine the morphologies. Hair fibers treated with 0.75% of HCl showed maximum improvement in all the properties and could be employed as reinforcement in various composites to be used for structural applications. [ABSTRACT FROM AUTHOR]

Rare earth silicates are promising environmental/thermal barrier coating (E/TBC) materials facing severe CMAS (CaO‐MgO‐Al2O3‐SiO2) corrosion. Previous studies mainly focused on the intrinsic properties of precorrosion coatings, but there were few studies on their CMAS corrosion products that play a crucial role in the performance of coatings in postservice stage. In this work, the mechanical and thermal properties of nine corrosion products between lutetium silicates and CMAS are studied using first‐principles calculations. Their differences of elastic stiffness are attributed to the different crystal structures and bonding strength. The T:O ratio is identified as a factor of the crystal structure for silicate products, and it has a good correlation with their elastic stiffness. Moreover, the divergences of thermal conductivity are dominated by three essential factors, that is, atomic vibration intensity, lattice vibrational anharmonicity, and complexity of crystal structure. Compared with rare earth silicates, six products, that is, the α‐CaSiO3, β‐CaSiO3, Ca2MgSi2O7, Ca2Al2SiO7, CaAl2Si2O8, and Ca2Lu8(SiO4)6O2, showing good damage tolerance and low thermal conductivities, are predicted to be advantageous to E/TBCs. These discoveries reveal the mechanical/thermal properties of corrosion products between lutetium silicates and CMAS and are expected to support the future researches on the performance of E/TBC in the postservice stage. [ABSTRACT FROM AUTHOR]

Background: Hyaluronic acid liquid‐core hydrogel beads (HA‐LHB) is a good way for oral intake of HA. However, HA may affect the reaction–diffusion of sodium alginate (SA) and Ca2+ leading to poor mechanical properties, since HA is a polyanionic electrolyte having electrostatic effect and a certain spatial site‐blocking effect. Results: The mechanical properties of HA‐LHB were modified from bathing solution, core solution and secondary calcium bath time. The mechanical properties varied with the SA structure and concentration in bathing solution, where SA with high G (guluronic acid) segment compounded with SA with high M (mannuronic acid) segment at a mass ratio of 7:3 with a 11 g kg−1 concentration showed the best mechanical properties. The secondary calcium bath can greatly improve the mechanical properties due to the tight network formed by bidirectional crosslinking, and 15 min reaction reached the plateau if Ca2+ is sufficient. And the mechanical properties were positively correlated with calcium lactate concentration only at <70 g kg−1 in core solution, but the diffusion of Ca2+ was hindered by the tight gel network at higher concentrations. Moreover, the mechanical properties can be maintained during heat treatment, due to the rearrangement of alginate network structure. Conclusion: Our results suggested that the problem of poor mechanical properties of LHB in the presence of high HA concentration can be avoided by process control, which may broaden the development of HA and popping boba market. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The present study explores the influence of Cobalt oxide nanoparticles(Co3O4 NPs) on the physicochemical characteristics of Poly(vinylalcohol)/ Chitosan (PVA/Cs) blend. Using a variety of techniques, the pure blend and the nanocomposites' composition, structure, optical, thermal, and mechanical properties, and antibacterial activity were characterized. The Co3O4 NPs were produced by precipitation method utilizing cobalt salt as the raw material. The crystalline nature of the nanoparticles and semi-crystalline behavior of the PVA/Cs are demonstrated by the XRD data. Adding nanoparticles to the pure blend reduced the intensity of the semi-crystalline. The rise in absorption intensity observed in UV-visible spectra upon the incorporation of Co3O4 NPs into the PVA/Cs blend indicates an improved dispersion of the nanoparticles within the blend. When Co3O4 NPs are added, the energy band-gap Egdir and Egind of PVA/Cs–Co3O4 samples greatly decrease. According to TGA data, the thermal stability of nanocomposites was significantly higher than that of the PVA/Cs blend, and it rose as the concentration of nanoparticles increased. When compared to neat PVA/Cs film, mechanical property investigation of PVA/Cs–Co3O4 nanocomposites films revealed enhanced features. The effectiveness of the PVA/Cs–Co3O4 nanocomposite films in inhibiting the growth of microorganisms was assessed by evaluating their antimicrobial activity (ANMAC) against a range of bacteria and fungi. The inclusion of Co3O4 NPs led to an increase in activity against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) bacteria as well as fungi Candida albicans and Aspergillus niger (C. albicans and A. niger). The addition of Co3O4 NPs to the PVA/Cs blend effectively improved the material's optical, thermal, mechanical, and antibacterial properties. This remarkable improvement stems from the Co3O4 NPs, which were introduced into the PVA/Cs blend in different amounts, leading to the development of novel nanocomposites. The outstanding properties of Co3O4/PVA/Cs nanocomposite films suggest their potential for applications in optoelectronics and food packaging. [ABSTRACT FROM AUTHOR]

In this study, poly(l-lactide-co-ε-caprolactone) (PLCL) block copolymers with an ABA structure were prepared using a two-step polymerization process, and their microstructures, thermal, and mechanical properties were systematically investigated based on the introduction of ε-caprolactone as a comonomer in the first step to form the B block. As a result, it was observed that as the content of the B block, or the ε-caprolactone comonomer increased, the average sequence length of l-lactide decreased, indicating that a potential impact on the crystallization behavior and thermal properties of the final PLCL block copolymers. However, the decrease in thermal properties, such as the melting temperature, was less significant than expected. For instance, the melting temperature of pure PLA in this study was 172.5 °C, whereas the PLCL block copolymer with 9 mol% ε-caprolactone comonomer had a melting temperature of 171.1 °C, showing a relatively minimal difference between the two samples. Additionally, as the ε-caprolactone content increased, tensile strength and initial modulus of the PLCL block copolymer slightly decreased, while the breaking strain significantly increased. This suggests that the two-step polymerization method proposed in this study is effective in imparting flexibility to PLA while minimizing its mechanical property degradation. Consequently, the introduction of comonomer such as the ε-caprolactone through controlled polymerization process offers valuable insights for developing PLA materials with diverse properties. [ABSTRACT FROM AUTHOR]

A novel epoxy resin, DPHP, was synthesized from diphenolic acid, which contains biobased levulinic acid, with triethylphosphite, to improve the flame retardancy of bisphenol‐A diglycidyl ether (BADGE) epoxy. Curing experiments were conducted using isophorone diamine as a curing agent for BADGE and DPHP mixtures. Variations in cure kinetics, mechanical properties, and flame retardancy were evaluated across different DPHP contents. The introduction of phosphorus functional groups into DPHP affected the polarization of epoxide CO bonds, resulting in reduced apparent activation energy for epoxy curing reactions. However, the higher epoxy equivalent weight of DPHP compared with that of BADGE led to a decrease in the tensile strength and the glass transition temperature of the cured material with increasing DPHP content. A significant increase in char yield for combustion of the epoxy blend was observed, ranging from 8.3% at 0 wt% DPHP to 20.1% at 50 wt% DPHP. Additionally, cone calorimeter measurements showed significant reductions in heat release rate and total heat release, leading to a decrease in fire spread from 1.07 MJm−2 s−1 at 0 wt% DPHP to 0.43 MJm−2 s−1 at 50 wt% DPHP. These results show that the flame retardancy of the cured material improved significantly as the DPHP content increased. [ABSTRACT FROM AUTHOR]

Highlights The objective of this study is to improve the properties of polylactic acid (PLA), a biopolymer produced from renewable resources, without compromising its environmentally friendly “natural composite” properties. The aim was to expand the application range of PLA by making it suitable for the production of high performance composites. With this in mind, it was decided to use inorganic and environmentally friendly materials such as basalt fiber (BF) and boric acid (BA) as reinforcements. Adhesive wear and tensile tests were used to investigate the tribological and mechanical performance of the composites. Differential scanning calorimetry (DSC) and dimensional stability analysis (DSA) methods were used to investigate the thermal properties. Scanning electron microscopy analysis was also used to investigate the morphological properties of the samples. In addition, a matrix modification process using Joncryl®, an epoxy‐based chain extender chemical, was applied to enhance the interfacial interaction between the composite components and improve the composite properties by improving the dispersion of reinforcing materials. As a result of the characterization tests, it was observed that a significant improvement in the properties of the material type containing 10 wt% BF, 0.25 wt% BA and 2 wt% Joncryl® was achieved. A 19% increase in tensile strength of this type of material was observed compared with unreinforced PLA, while the sharp peak increase in the coefficient of friction (COF) curve was shifted from 20 m to 60 m. As a result, it has been presented that environmentally friendly and inorganic materials such as BF and BA can be used to produce composite materials that will serve sectors where the need and use of high performance materials is intense, especially in the automotive, aerospace and aviation sectors. The properties of PLA matrix composites were improved by the simultaneous use of BF and BA and the addition of Joncryl®. The structural properties of PLA, an environmentally friendly polymer, have been improved without compromising this characteristic. PLA matrix natural composites with performance that can be used in the automotive, aerospace and aviation sectors have been developed. [ABSTRACT FROM AUTHOR]

In this study, we successfully realized the hydrolytic ring-opening co-polymerization of ε-caprolactam (CPL) and lysine derivative. A novel antibacterial modified polyamide 6 with a branched structure was obtained after the quaternization of the co-polymers. The co-polymers exhibited a significant increase in zero shear viscosity, melt index and storage modulus at the low frequency region. The quaternized co-polymers displayed thermal properties different from pure PA6 and good mechanical (tensile) properties. The antibacterial activity of the quaternized co-polymers depends on the quaternary ammonium groups' incorporated content. At 6.2 mol% incorporation of quaternary ammonium groups, the strong antibacterial activity has been introduced to the co-polymers. As the quaternary ammonium groups approached 10.1 mol%, the antibacterial polymers demonstrated nearly complete killing of Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). The above research results provided a new approach for the study of high-performance nylon. [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]

Highlights The work summarizes an innovative nanocomposite including synthesized copper nanoparticle (CuNP) impregnated wheat straw (WS) (the agronomic waste from an wheat plant) reinforced unsaturated polyester resin has been established. The addition of nanoparticles (NPs) increased the antifungal properties (~11%), durability (~9%), and strength (~39%) of the composites. Therefore, these nanoparticles have been synthesized from a copper chloride dihydrate precursor and they have been impregnated into wheat straw via cationization. This copper‐impregnated wheat straw (CuIWS) was formulated and employed to create a strong and long‐lasting nanocomposite with unsaturated polyester resin. Their morphological, mechanical, chemical, biodegradability (BD), and thermal properties were estimated and relationships were explicated systematically. Particularly, the tensile strength of polyester resin, crude and treated WS (cationized and copper‐impregnated) composites were 11.70, 14.20, 20.92, and 22.34 N/mm2 respectively. Therefore the reinforcement capability for crude, cationized and copper‐impregnated WS composites increased by ~22%, 75%, and 92% respectively. The residual ash was just about 16.23%, 12.04% and 6.56% for copper impregnated wheat straw composite (CuIWSC), Cationized wheat straw composite (CWSC) and untreated wheat straw composite (UTWSC) respectively point to the existence of ~4.1% Cu incorporated into the wheat straw which holds up the energy dispersive x‐ray (EDX) spectra of ~4.2% copper content. Thermogravimetric analysis (TGA) indicates that the nanocomposites are stable up to 325°C. These nanocomposites also show superlative crystallinity compared to other ones. Water uptake capacity followed typical Fickian diffusion law. The developed nanocomposites might be suitable for automobile and aircraft parts, furniture, and other indoor to outdoor applications. TS of the composites increased by increasing the WS filling up to 15%. The crystallinity increased after the addition of nanoparticles. The typical water uptake properties followed the Fickian diffusion rule. Incorporation of nanoparticles increased 11% antifungal properties. The developed nanocomposites are used for inside and outside applications. [ABSTRACT FROM AUTHOR]

The increase in operating temperature contributes to improving the performance and fuel utilization efficiency of gas turbines. However, it also places thermal barrier coatings (TBCs) in a more demanding working environment, requiring higher sintering resistance and better mechanical properties. In the present study, HfO2 was introduced into the dual‐phase LaYbZr2O7 system as a doping oxide to form the LaYb(HfxZr1−x)2O7 system. The research concentrated on its phase composition, mechanical properties, and thermophysical properties. The results show that substituting Hf for Zr does not alter the dual‐phase structure of the system. The mutual inhibition between the two phases and the inherent material‐binding capability of Hf further reduce the grain size compared to pure LYZO. Additionally, the presence of Hf reduces the tendency of Frenkel defect formation and cation migration frequency, effectively inhibiting ion diffusion and thereby suppressing the densification and shrinkage trends of the material. The system retains relatively high hardness, fracture toughness, and low elastic modulus of the LYZO matrix, with a decrease in thermal conductivity and an increase in infrared reflectivity. These results suggest that Hf doping enhances the sintering resistance of LYZO material, making them promising for high‐temperature TBCs. Our study presents a viable approach to enhance the sintering resistance of LYZO, and this methodology can be extrapolated to other rare‐earth zirconates. [ABSTRACT FROM AUTHOR]

Highlights The over‐loading of heat‐resistant fillers in silicone rubber creates a contradiction between heat resistance and mechanical properties, thus greatly limiting the durability of silicone rubber products in cutting‐edge applications and complex scenarios. To address this issue, silicone rubber was filled with octavinyl polyhedral oligomeric silsesquioxane (POSS) and carbon nanotubes (CNT) and crosslinked with 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane (DBPMH) in an attempt to obtain composites with excellent mechanical properties and great thermal stability. Optical microscopy and X‐ray diffraction analyses revealed the size of POSS crystals decreased and the characteristic peaks disappeared after the peroxide crosslinked the polymer at elevated temperature. Specifically, silicone rubber composite filled with 0.1 phr POSS and 1.0 phr CNT exhibited a tensile strength of 10.2 MPa and elongation at a break of 450%. Further, the strength and elongation could be kept after thermo‐oxidative aging at 250°C for 32 h. Thermogravimetric analysis results demonstrate that the addition of POSS and CNT into silicone rubber exhibits a synergistic effect, markedly improving the thermal stability of the material. This method provides a valuable reference for manufacturing silicone rubber products that possess both excellent mechanical properties and high thermal stability under extreme working conditions. A novel silicone rubber composite with excellent mechanical properties and thermal stability was prepared. A small amount of octavinyl polyhedral oligomeric silsesquioxane (POSS) and carbon nanotubes exhibited a synergistic effect to improve thermal stability. The dependence of the morphological evolution of POSS crystals in SR on the 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane and temperature was studied. [ABSTRACT FROM AUTHOR]

This paper is the first to look at the structural, electronic, mechanical, optical, and thermodynamic properties of the ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) half‐Heusler (HH) using DFT based first principles method. The lattice parameters that we have calculated are very similar to those obtained in prior investigations with theoretical and experimental data. The positive phonon dispersion curve confirm the dynamical stability of ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The electronic band structure and DOS confirmed that the studied materials ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) are direct band gap semiconductors. The investigation also determined significant constants, including dielectric function, absorption, conductivity, reflectivity, refractive index, and loss function. These optical observations unveiled our compounds potential utilization in various electronic and optoelectronic device applications. The elastic constants were used to fulfill the Born criteria, confirming the mechanical stability and ductility of the solids ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn). The calculated elastic modulus revealed that our studied compounds are elastically anisotropic. Moreover, ANiX (ASc, Ti, Y, Zr, Hf; XBi, Sn) has a very low minimum thermal conductivity (Kmin), and a low Debye temperature (θD), which indicating their appropriateness for utilization in thermal barrier coating (TBC) applications. The Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv) are determined by calculations derived from the phonon density of states. [ABSTRACT FROM AUTHOR]

This study explores the influence of mold temperatures below 60(C on thermoplastic polyurethane (TPU) properties during injection molding, focusing on phase separation and its impact on mechanical, thermal, and viscoelastic properties. Using a combination of micro-indentation, temperature scanning stress relaxation, and conventional characterization methods, the research highlights how increased mold temperatures promote more distinct phase separation, enhancing mechanical stability and physical properties. The novel use of micro-indentation revealed a gradient in material stiffness from the surface to the core of injection-molded samples, attributed to differential cooling rates and shear forces, which affect phase separation and crystallinity of the hard domains. These insights are critical for applications requiring specific surface properties and underscore the importance of understanding the interplay between chemical composition and processing conditions for optimizing TPU properties. Furthermore, the paper shows that tensile testing, differential scanning calorimetry, and Shore hardness cannot quantify the effects of mold temperatures below 60(C. The research highlights the influence and importance of chemical composition, rheological history, and thermal history on the properties of TPU. [ABSTRACT FROM AUTHOR]

This study reports the design and preparation of thermoplastic polyurethane (TPU), TPU/Cloisite 30B (0.4, 0.8, and 1.2 wt %) nanocomposites, and TPU/Irganox 1010 (0.5, 1, and 1.5 wt%) through a semi-batch method in an internal mixer and glass reactor. For this purpose, poly (ethylene adipate) was reacted with 4,4'-methylene diphenyl isocyanate to obtain the prepolymer and subsequently cured with 1,4-butanediol (BD) as chain extender to obtain the TPU sample. To accurately evaluate the curing reaction time (6 min), samples were taken from the internal mixer at specified intervals and then subjected to ATR-FTIR analysis (at 2, 4, and 6 min). Good distribution and dispersion of nanoclays in the resulting TPU nanocomposites were confirmed by XRD and scanning electron microscopy. Thermogravimetric analysis showed that the T5% and T50% of the TPU nanocomposite (TPU/Cloisite 30B (1.2 wt%)) were 15 and 33 °C higher compared to TPU-Internal. Similarly, the tensile strength of the TPU nanocomposite (TPU/Cloisite 30B (1.2 wt%)) was improved by about 25% compared to TPU-Internal. DMTA analysis revealed that the tan δ was decreased due to steric hindrance of Irganox 1010 on TPU chain mobility. Additionally, the tanδ peak for TPU-Internal was shifted from − 5.35 °C to 7.10 °C and − 1 °C for TPU 6 and TPU 3, respectively. [ABSTRACT FROM AUTHOR]

The promotion of different properties of polymers has become a substantial worldwide objective for different counterparts in industry and academia. In this work, different loadings of multi walled carbon nanotubes (MWCNTs) were employed to reinforce acrylonitrile butadiene styrene (ABS) to prepare polymer nanocomposites. The employed loadings by solution blending approach were (0.1, 0.5, 1.0, and 5.0) wt. %. FTIR and XRD were utilized to investigate the chemical interaction and crystal structure; respectively. The morphological investigation performed by scanning electron microscopy (SEM) showed the nature of the neat polymer, the dimensions and orientations of the nanotubes, and the good dispersion of the nanotubes within the polymer for the loadings up to 1.0 wt. %. As a result of this good dispersion, thermal properties represented by thermal degradation temperature (Td) and glass transition temperature (Tg) were improved. Furthermore, Young's modulus and tensile strength for the nanocomposite of 1.0 wt. % were enhanced by 87% and 46%, respectively as compared to the neat polymer. [ABSTRACT FROM AUTHOR]

Al–Zn–Mg–Cu alloys have been prepared using the gravity die-casting process. The influence of copper addition on microstructure, mechanical and thermal properties are studied. The experimental alloys were prepared using 5754 alloys, Al–Cu alloys, and pure zinc (solid form). Alloys are mechanically stirred for uniform distributions of alloying elements and precipitate phases. Four alloys with different copper weight percentages (0.02 wt%, 0.89 wt%, 1.57 wt%, and 3.34 wt%) were prepared. The α-Al and η (MgZn2) phases are observed in as-cast Al–Zn–Mg alloy. The addition of copper in Al–Zn–Mg alloys formed a θ phase (Al2Cu). Micro-Vickers hardness of Al–Zn–Mg–Cu alloy increased (from 116 HV1 to 133 HV1) with copper addition (0.02–1.57 wt%) at firstly due to the formation of θ phase (Al2Cu). Then, micro-Vickers hardness decreases due to high amounts of precipitates. Copper addition reduces the melting point (623–612 °C) and precipitation temperature (472–466 °C) of aluminum alloy. Al–Zn–Mg alloys have tensile strength of 422 MPa due to precipitates phase formation of η and T phases, solid solution strengthening (zinc and magnesium). Copper addition increases tensile strength due to the formation of θ phases. After achieving a strength of 486 MPa at an elongation of 3.72% (1.57 wt% Cu), tensile strength reduces due to a higher amount of precipitates. [ABSTRACT FROM AUTHOR]

SiO2f/SiO2 composites were prepared by compression molding and sintering using short-cut quartz fibers as reinforcement. The effects of fiber volume fraction (15%∼35%) on bulk density, apparent porosity, and mechanical and thermal properties of the composites were investigated. The results indicated that the samples with 25% fiber volume fraction had the best comprehensive performance, with an apparent porosity and compressive strength of 36% and 46.3 MPa, respectively. The flexural strength of the samples was 13.9 MPa, which represented a 90% increase compared to the samples without fibers. It was attributed to the occurrence of fiber debonding and fiber pull-out in the porous matrix. Meanwhile, the residual strength ratio of the samples after 20 thermal shocks was 74.8%. In addition, the average coefficient of thermal expansion was 0.95 × 10− 6/℃ at 300 ℃∼700 ℃ and the thermal conductivity was 0.388 W·m− 1·K− 1 at 800 °C. This approach can satisfy the requirements of low cost, fast preparation of SiO2f/SiO2 composites, which offers the prospect of its application in the integration of load-bearing and thermal insulation. [ABSTRACT FROM AUTHOR]

This research aims to highlight the importance of diverse forms of graphitic carbon nitride (g-C3N4) as strengthening elements in epoxy composites. It explores the influence of three different forms of g-C3N4 and their concentrations on the mechanical properties of the epoxy composites. Various characterization techniques, such as scanning electron microscopy (SEM), dynamic light scattering (DLS), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR), were utilized to comprehend the effects of g-C3N4 morphology and particle size on the physical and chemical characteristics of epoxy resin. Mechanical properties, such as tensile strength, strain, modulus, and fracture toughness, were determined for the composite samples. SEM analysis was performed to examine crack morphology in samples with different reinforcements. Findings indicate that optimal mechanical properties were achieved with a 0.5 wt% bulk g-C3N4 filler, enhancing tensile strength by 14%. SEM micrographs of fracture surfaces revealed a transition from brittle to rough morphology, suggesting increased toughness in the composites. While the TGA results showed no significant impact on degradation temperature, dynamic mechanical analysis demonstrated a 17% increase in glass transition temperature. Furthermore, the improvement in thermal breakdown up to 600 °C was attributed to reinforced covalent bonds between carbon and nitrogen, supported by FTIR results. [ABSTRACT FROM AUTHOR]

Functional nanocomposites have garnered considerable attention due to their ability to exhibit multifunctional properties and achieve exceptional performance. This current paper aims to analyze the individual and combined effects of magnetite (Fe3O4) and Graphene nanoplatelets (GNPs) on the mechanical, thermal, and morphological properties of a blend consisting Thermoplastic elastomer (TPE) which is made up of Natural rubber (NR) and Polyaniline (PANi). Both nanocomposites were fabricated via melt blending method using an internal mixer, followed by compression via hot/cold pressing. The incorporation of Fe3O4 was observed to consistently enhance the flexural and impact properties compared to GNP-based nanocomposites. Notably, the nanocomposites filled with 6 wt% Fe3O4 displayed the highest flexural strength (2.1 MPa), flexural modulus (31.1 MPa), and impact strength (4.4 kJ/m2). Results from thermogravimetric analysis and differential scanning calorimetry demonstrated a significant improvement in thermal stability within the nanocomposites. The introduction of nanoparticles led to a delay in decomposition and melting processes. The hybridization of Fe3O4 and GNP proved effective in synergistically enhancing both mechanical performance and thermal stability. At optimum content, scanning electron microscopy micrographs revealed a uniform dispersion of Fe3O4/GNPs within the TPE-PANi blend, accompanied by strong interactions between the components. [ABSTRACT FROM AUTHOR]

Purpose: One of the low-cost minerals that can be used as reinforcing filler in polymer industry is pumice powder. Pumice is a highly porous volcanic glass formed during explosive eruptions. This pumice has received significant interest because of its large surface area with various polar groups and can be processed easily. Design/methodology/approach: This study is carried out to investigate the effect of partial replacement of silica (as traditional filler) by naturally occurring pumice powder to improve the thermal and mechanical properties of nitrile butadiene rubber cured with electron beam radiation (doses from 25 to 150 kGy). Findings: The results indicated that the addition of pumice powder increase the tensile strength at lower doses up to 75 kGy (especially at concentration of 5 phr). Besides, an improvement in the thermal stability was attained with the addition of pumice powder. Originality/value: Pumice powder is volcanic-based alumina and silica which is mainly composed of SiO2. It has porous structure which is formed by dissolved gases precipitated during the cooling as the lava hurtles through air. Due to its porous structure, it has low density and high thermal insulation. It also has high temperature and chemical resistance, for these reasons it became preferable material to be used as filler in the plastic and rubber industry. [ABSTRACT FROM AUTHOR]

Ceramic fibers are an important thermal insulation material that are not only widely used in extreme conditions, but also play an important role in energy conservation and energy efficiency for sustainable development. However, the practical application of conventional ceramic fibers has a high thermal conductivity in high-temperature environments, which hinders their widespread application. Here, a novel lamellar structured porous SiTiOC/C composite ceramic materials was designed and prepared with excellent thermal insulating properties. The unique microstructure endowed the porous SiTiOC/C composite ceramic materials with a high IR refractive index (93.81%) and an ultra-low thermal conductivity (0.0562 W·m−1 K−1 at 600 ℃). In addition, the porous SiTiOC/C composite ceramic materials not only exhibited excellent mechanical properties (4.46 MPa at 800 ℃), but also demonstrated impressive oxidation resistance and thermal stability. In summary, the proposed porous SiTiOC/C composite ceramic materials provide a reference for the development of high-temperature insulation with good mechanical properties. [ABSTRACT FROM AUTHOR]

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Ag-nanoparticle-reinforced polymethyl methacrylate (AgNP/PMMA) composites are widely used in healthcare, electronics, construction, transportation and many other fields. As the service temperature fluctuates easily, it is necessary to study the temperature effect on the properties of AgNP/PMMA composites. In this work, a preparation method of mixing and hot-pressing was used to fabricate multifunctional AgNP/PMMA composites that are suitable for large-scale industrial production. AgNPs are found to disperse homogeneously in the PMMA matrix. The thermal conductivity of the composite with 15 vol% AgNPs is 116.19% higher than that of PMMA and decreases as the temperature rises. Flexural strength increases first and then decreases with the rising of AgNP content and service temperature, while the flexural modulus decreases gradually. The minimum electrical resistivity of the composite achieves 1.37 × 10−3 Ω·m, with a low percolation threshold of 5 vol%, an improvement of nine orders of magnitude over PMMA. The results demonstrate that the service temperature has a significant effect on the comprehensive properties of AgNP/PMMA composites. [ABSTRACT FROM AUTHOR]

This study investigated the influence of fiber loading and maleated polyethylene (MAPE) coupling agent on the structural, thermal, mechanical, morphological properties, and torque rheology of high-density polyethylene (HDPE) reinforced with Posidonia oceanica fiber (POF) composites. HDPE/POF composites, both with and without MAPE, were manufactured using a two-step process: composite pellets extrusion, followed by test samples injection molding with various POF loadings (0, 20, 30, and 40 wt%). HDPE/POF composites reinforced with higher loading of POF (40 wt%) exhibit superior stiffness, better crystallinity, and higher stabilized torque and mechanical energy (Em) compared to other composite formulations. Therefore, varying the POF loading leads to extrusion and injection processing variations. Furthermore, the coupling agent significantly enhances the tensile strength, ductility, impact strength, crystallinity, stabilized torque, and Em of the HDPE/POF composite. This improvement is due to the enhanced interfacial adhesion between the POF and the HDPE matrix with the addition of the MAPE, as supported by the Scanning Electron Microscopy (SEM) micrographs. [ABSTRACT FROM AUTHOR]

Hybridization of natural fibers with ceramic materials for reinforcing composites allows the optimization of the properties of these materials. For this reason, the present study aims to investigate physical, mechanical, water absorption, swelling and thermal properties as well as morphological characteristics of a hybrid Paederia foetida fibers–alumina powder (PFs–Al2O3)‐reinforced epoxy composite. Epoxy resin served as the matrix, while PFs and Al2O3 were employed as reinforcement. Five types of composites were fabricated using the hot‐pressing technique. The corresponding ratios of PFs:Al2O3 volume fractions (%) considered here were 0:40 (SFA), 10:30 (SFB), 20:20 (SFC), 30:10 (SFD) and 40:0 (SFE). The results reveal that the density of the hybrid PFs–Al2O3 composites decreased for increasing volume fractions of PFs: from 2.173 g cm−3 of SFA to 1.042 g cm−3 of SFE. The highest values of tensile strength (i.e. 49.085 MPa), tensile elastic modulus (i.e. 1.431 GPa) and impact strength (24 kJ m−2) were obtained for the SFD composite material with 30% volume fraction of PFs and 10% volume fraction of Al2O3: this happened because interface bonds between PFs, Al2O3 and epoxy phases achieved their optimal configuration. Overall, mechanical properties of the hybrid PFs–Al2O3‐reinforced epoxy composites were superior to those of composites reinforced only by PF fibers or only by Al2O3. Water absorption and swellability reached their maximum values at the steady state occurring after tested samples remained immersed in water for 820 h. The SFE composite reinforced only by PFs presented the highest water absorption and swelling (i.e. 6.034% and 5.81%, respectively) while for all other hybrid composites (SFD, SFC and SFB) these two quantities remained below 5%. Density and volume fraction of voids of hybrid PFs–Al2O3‐reinforced composites were consistent with the corresponding properties of the composites reinforced only by Al2O3 or PFs. SFD was also the most thermally stable material. Scanning electron microscopy observations of fractured surfaces indicated that the microstructure of the PFs–Al2O3‐reinforced epoxy composites presents several voids, fiber pullouts and transverse fibers, which together optimize the mechanical response of the composite material. Remarkably, the SFD composite material was highly competitive with the most recently developed hybrid composites employing natural reinforcements. © 2024 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Highlights The influence of nanofillers (cellulose nanofibers (CNF) and halloysite nanotubes (HNTs)), and basalt fibers (BF) on the morphology, mechanical and thermal of recycled polyamide 6 (PA6) composites were investigated through scanning electron microscopy (SEM), mechanical testing, rotational rheometry, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). CNF, HNTs and BF were relatively well‐dispersed in the PA6 matrix and the incorporation of these nanofillers and BF increased the strength of the matrix, which indicates a good dispersion of the nanofillers and BF. CNF and HNTs‐filled PA6 nanocomposites increased the tnsile strength by 14% and 6% compared to the neat PA6, respectively. The composites elongation at break decreased with nanofiller, BF and combined nanofillers and BF. The shear storage modulus values of PA6/20B5C, PA6/20B5H, and PA6/25B are significantly elevated compared to neat PA6, with increases of 3.7, 2.8, and 2.5 times, respectively, at an angular frequency of 100 rad/s. PA6/20B5H composites with 20 wt.% BF and 5 wt.% HNTs exhibited the highest storage modulus (9.5 GPa) from the DMA study. Thermal stability and ash content at 800°C increased with the incorporation of HNTs and BF. The DSC findings showed that the glass transition (Tg) and melting temperature (Tm) of the composites did not exhibit any notable changes when nanofillers and BF were added to the resin. The nucleation ability of PA6 was enhanced attributable to BF and hybridization of BF and nanofillers since the crystallization temperatures of PA6 in BF filled and hybrid composites were around 5°C greater than neat PA6. The results suggest hybrid composites with potential environmental characteristics and higher mechanical properties can be utilized in semi‐structural applications in automotive and construction as a sustainable and lightweight alternative to steel and other materials. The addition of HNTs, CNF, BF and hybridization of nanofillers with BF reduced the brittleness of PA6. Nanoreinforced and hybrid PA6 composites achieved higher storage modulus than neat PA6. Thermal stability and ash content increased with the incorporation of HNTs and BF. The hybrid composites have a higher complex viscosity compared to PA6. The sustainable hybrid composites can be utilized in automotive and construction industries. [ABSTRACT FROM AUTHOR]

Epoxy resins (EPs) are highly coveted as insulating materials for engineering applications. However, their limited mechanical properties and inadequate thermal conductivity at cryogenic temperatures significantly restrict their range of applications. Herein, a novel approach was introduced for crafting EP composites infused with boron nitride (BN) using hyperbranched polymer (HBP) grafting. The resulting HBP‐BN was uniformly dispersed within the EP and securely bonded to the matrix through robust chemical interactions, significantly improving the property enhancement efficiency of HBP‐BN on EP. Thus, the mechanical strength of EP/HBP‐BN composites was significantly enhanced, with maximum tensile and impact strengths achieved at 6 and 4 wt% HBP‐BN content. These values exceeded those of pure EP by 47% and 22% at room temperature (RT) and increased even more substantially to 72% and 135% at 77 K. Moreover, the composite demonstrated a remarkable 430% improvement in thermal conductivity, reaching 1.1627 W·m−1·K−1, when the HBP‐BN content reached 40 wt%. Simultaneously, EP/HBP‐BN composites exhibit low dielectric permittivity and high volume resistivity, signifying exceptional electrical insulation properties. HBP‐BN substantially enhances the cryogenic properties of EP composites, offering an efficient pathway for the utilization of EPs in engineering applications. Highlights: A novel method to enhance the cryogenic properties of EP was introduced.HBP‐BN significantly improves the cryogenic properties in EP composites.The composites are of significant interest for various engineering applications. [ABSTRACT FROM AUTHOR]

In this study, a novel branched polyamide 6 has been synthesized via the hydrolytic ring-opening co-polymerization of ε-caprolactam (CPL) and α-Amino-ε-caprolactam (ACL). The NMR characterization proves the existence of a branched chain structure. The rheological test determines that there is a remarkable increase in the melt index (MFR), zero shear rate viscosity, and storage modulus in the low-frequency region. The shear-thinning phenomenon becomes more obvious. The thermal properties tested by differential scanning calorimetry (DSC) show that the melting point and crystallinity of co-polymers decrease with the incorporation of ACL. However, the crystal structure of the samples only exhibits a slight change. When the ACL content in the feed is 1 wt%, the tensile strength and fracture elongation rate of the co-polymers show a significant enhancement. [ABSTRACT FROM AUTHOR]

Polymer biocompositions of poly(3-hydroxybutyrate) (P3HB) and linear polyurethanes (PU) with aromatic rings were produced by melt-blending at different P3HB/PU weight ratios (100/0, 95/5, 90/10, and 85/15). Polyurethanes have been prepared with 4,4′-diphenylmethane diisocyanate and polyethylene glycols with molar masses of 400 g/mol (PU400), 1000g/mol (PU1000), and 1500 g/mol (PU1500). The compatibility and morphology of the obtained polymer blends were determined by infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). The effect of the polyurethane content in the biocompositions on their thermal stability and mechanical properties was investigated and compared with those of the native P3HB. It was shown that increasing the PU content in P3HB-PU compositions to 10 wt.% leads to an improvement in the mentioned properties. The obtained results demonstrated that the thermal stability and mechanical properties of P3HB were improved, particularly in terms of increasing the degradation temperature, reducing hardness, and increasing impact strength. The best thermal and mechanical properties were shown by the P3HB-PU polymer compositions containing 10 wt.% of polyurethane modifiers, especially PU1000, which was also confirmed by the morphology analysis of these biocompositions. The presence of polyurethanes in the resulting polymer biocomposites decreases their glass transition temperatures, i.e., makes the materials more flexible. The resulting polymer biocompositions have suitable mechanical properties and thermal properties within the processing conditions for the predicted application as biodegradable, short-lived products for agriculture. [ABSTRACT FROM AUTHOR]

The manufacturing method influences the properties of the produced components. This work investigates the influence of manufacturing methods, such as fused deposition modeling (3D printing) and injection molding, on the water absorption and mechanical and thermal properties of the specimens produced from neat bio-based poly(lactic acid) (PLA) polymer and poly(lactic acid)/wood composites. Acrylonitrile butadiene styrene (ABS) acts as the reference material due to its low water absorption and good functional properties. The printing layer thickness is one of the factors that affects the properties of a 3D-printed specimen. The investigation includes two different layer thicknesses (0.2 mm and 0.3 mm) while maintaining uniform overall thickness of the specimens across two manufacturing methods. 3D-printed specimens absorb significantly higher amounts of water than the injection-molded specimens, and the increase in the layer thickness of the 3D-printed specimens contributes to further increased water absorption. However, the swelling due to water absorption in 3D-printed specimens decreases upon increased layer thickness. The tensile, flexural, and impact properties of all of the specimens decrease after water absorption, while the properties improve upon decreasing the layer thickness. Higher porosity upon increasing the layer thickness is the predominant factor. The results from dynamic mechanical analysis and microscopy validate the outcomes. The results from this experimental study highlight the limitations of additive manufacturing. [ABSTRACT FROM AUTHOR]

The physical properties as well as thermal and electrical stability of copper particles can be improved by surface protection, which mainly depends on the coating material. Our study was, therefore, focused on the rheological, thermal, mechanical and electrical characterization of polymer composites by comparing uncoated (Cu), silver-coated (Cu@Ag) and silica-coated (Cu@Si) copper flakes in low-density polyethylene at various volume concentrations (up to 40%). Interactions among particles were investigated by rheological properties, as these indicate network formation (geometrical entanglement), which is important for mechanical reinforcement as well as establishing an electric pathway (electrical percolation). The results showed that geometrical and electrical percolation were the same for Cu and Cu@Si, ~15%, while, surprisingly, Cu@Ag exhibited much lower percolation, ~7.5%, indicating the fusion of the Ag coating material, which also decreased crystal growth (degree of crystallinity). Furthermore, the magnitude of the rheological and mechanical response remained the same for all investigated materials, indicating that the coating materials do not provide any load transfer capabilities. However, they profoundly affect electron transfer, in that, Cu@Ag exhibited superior conductivity (74.4 S/m) compared to Cu (1.7 × 10−4 S/m) and Cu@Si (1.5 × 10−10 S/m). The results obtained are important for the design of advanced polymer composites for various applications, particularly in electronics where enhanced electrical conductivity is desired. [ABSTRACT FROM AUTHOR]

Polyamide composites with varying filler concentrations are prepared using the hot melt extrusion method, employing polyamide 56/6 (PA56/6) and modified talc as fillers. Initially, the thermal characteristics of PA56/6 composites (PA56/6‐talc) are examined through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), encompassing parameters such as melting temperature, crystallinity, and decomposition temperature. The hydrophilicity and barrier properties of PA56/6‐talc are assessed using an optical contact angle meter, a water vapor transmission rate tester, and an oxygen transmission rate tester. Furthermore, the mechanical properties of PA56/6‐talc are also scrutinized. The results indicate that PA56/6 exhibits superior hydrophobic, barrier, and mechanical properties, thereby demonstrating its immense potential in garment fabrics and packaging materials. [ABSTRACT FROM AUTHOR]

Highlights This study aims to enhance the properties of biodegradable plastics by blending poly(lactic acid) (PLA) as well as poly(butylene succinate) (PBS) with silicon carbide (SiC). SiC content was varied from 10 to 40 phr using an internal mixer, maintaining a 90/10 wt% ratio of PLA/PBS as the matrix. The investigation covered mechanical, thermal properties, chemical structure, and composite morphology. The morphological analysis confirmed even dispersion of SiC within the PLA/PBS matrix, possibly due to improved compatibility via a silane coupling treatment. This resulted in the maximum Young's modulus and impact strength with 40 phr SiC, showing a 40% and 76% enhancement, respectively, compared to pure PLA. Concerning thermal properties, SiC addition influenced the mobility of PLA/PBS molecular chains and crystalline structure, leading to an increase in Tg with higher SiC fractions. However, ΔHm of PLA, PBS, and Xc,PLA decreased, which corresponds to reduced viscosity in the PLA/PBS blend and increased mobility with higher SiC content, as indicated by the elevated MFI value. Young's modulus increased by 40% and impact strength by 76% than pure PLA. Even SiC dispersion in PLA/PBS, possibly aided by silane coupling. SiC alters chain mobility, boosts crystalline structure, raising Tg. ΔHm and Xc,PLA reduced, suggests reduced viscosity in PLA/PBS at more SiC. Elevated MFI value shows increased chain mobility in PLA/PBS blend at more SiC. [ABSTRACT FROM AUTHOR]

The customization of polymeric prototypes is available to meet the specific needs of individual patients, considering tissue location and patient‐specific characteristics. Poly (butylene adipate‐co‐terephthalate) (PBAT) has shown great promise among various polymers in this scenario due to its biodegradability and processability properties. However, the effect of geometry changes on the mechanical properties of PBAT 3D scaffolds and their mechanical stability after in vitro degradation are crucial to determining the final application. This study focuses on the structural, morphological, and mechanical characterization of PBAT prototypes with different architectures and evaluating their mechanical properties before and after in vitro degradation. Three‐dimensional structures were 3D printed with rectilinear deposition angles of 15°, 30°, 45°, 60°, 75°, and 90°. Mechanical tests revealed that the prototype architecture influenced the stiffness, elongation, and maximum tension, where a greater resistance was observed for filaments containing the lowest angles. The thermal stability of PBAT remained unaffected either by reprocessing or hydrolytic degradation; however, in vitro degradation affected the mechanical behavior by increasing the stiffness and decreasing the elongation of the scaffold. Biological assays have demonstrated the nontoxic nature of PBAT and its potential to promote cell viability at a rate of 95%. These findings underscore the possibility of optimizing the PBAT design and structure to tune the mechanical properties and contribute to advancing tissue engineering strategies. [ABSTRACT FROM AUTHOR]