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Highlights The aim of this work to fabricate bamboo (B)/oil palm (O) fibers based biocomposites to assess mechanical, thermal and morphological properties. Flexural strength and modulus of hybrid biocomposite (7B:3O) exhibited a higher value (71.18 MPa and 5.24GPa) respectively among all biocomposite samples. On the other hand, pure biocomposite (B) showed a higher impact strength value (6977.8 J/m2) compared to other biocomposites. The results of TGA showed that thermal stability was observed significantly for hybrid biocomposites compared to other samples. In addition, the maximum decomposition temperature values were displayed in the hybrid biocomposite (5B5O), which was 377.82°C. Through DMA, it was likely to find the storage modulus curves (E′), loss modulus (E″) and damping factor (tan δ) for the biocomposites. The E′ showed an increase in the (3736.84 MPa) contrasted to other corresponding samples which were 3121.81 MPa, and 3209.67 MPa for 3B7O MPa and 5B5O samples, respectively. Overall, the results of DMA displayed an enhancement in the storage modulus (E′) in terms of the hybrid biocomposites representing greater stiffness and lower damping factor. SEM micrographs were utilized to understand the fiber bonding and fiber adhesion with the epoxy matrix. Furthermore, it confirmed SEM results that hybrid natural fibers enhance the complete characterisations of bio‐epoxy materials. Additionally, SEM images of the tensile fracture surfaces discovered voids and cracks. Finally, it can be concluded that the selection for the developed hybrid biocomposites provides excellent and economical lightweight biomaterials for automotive, aerospace, contractions and building components. Green hybrid biocomposites by oil palm/bamboo fiber/bioepoxy resin. Mechanical, thermal, DMA of hybrid composites carried out. Hybrid biocomposite(7B:3O) exhibited higher flexural strength value (71.18 MPa). TGA showed that the biocomposites are thermally further stable. DMA displayed an enhancement in the storage modulus (E′). [ABSTRACT FROM AUTHOR]

Highlights In this paper, carboxyl‐terminated nitrile rubber (CTBN) and Nano cerium oxide (n‐CeO2) were used to toughen epoxy resin (EP), and the effects of toughening agents on the mechanical and thermal properties of EP were studied. Orthogonal experiments determined that the ideal toughener proportions are 20 wt% CTBN and 1 wt% n‐CeO2, under which the resin demonstrated superior mechanical characteristics. The combined application of CTBN and n‐CeO2 significantly enhanced the resin's mechanical properties, surpassing the effects of individual particle toughening. Compared with pure EP, the impact, flexural, and tensile strengths of the resin‐cured product synergistically toughened by CTBN and n‐CeO2 increased by 462%, 136%, and 110%, respectively, and the flexural and Young's moduli increased by 38% and 35%, respectively. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize the cured resin. The results indicate that incorporating CTBN and n‐CeO2 reduces the reaction activation energy, thereby accelerating the curing reaction and facilitating its progression. The addition of nanoparticles enhances the maximum weight loss temperature of the cured resin, thereby improving its thermal stability. CTBN and n‐CeO2 particles create a uniform phase separation structure within the resin, enhancing its toughness and strength. Furthermore, the impact fracture mode of the cured resin transitions from brittle to tough fracture, demonstrating a significant toughening effect. This provides an effective method for the toughening modification of EP. The synergistic use of CTBN and n‐CeO2 enhances the toughness of EP. The incorporation of nanoparticles improves the thermal stability of the cured resin. The addition of CTBN and n‐CeO2 accelerates the curing reaction rate. The inclusion of toughening agents transforms the fracture mode of the cured resin from brittle to tough fracture. [ABSTRACT FROM AUTHOR]

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. Highlights: 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]

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]

High‐density polyethylene (HDPE) nanocomposites containing different optimized fractions of carbon nanofiber (CNF) at 6 wt.%, polyethylene glycol (PEG) at 4 wt.%, and copper oxide (CuO) nanorods in concentration ranges of 0.15, 0.5, and 2 wt.% were successfully melt processed using corotating twin extrusion and compression molding technique. The effect of PEG and CuO nanofiller on the HDPE matrix were studied, particularly for the percolation threshold for electrical conductivity, structural morphology, and other properties including thermal stability, thermal conductivity (TC), dielectric, and UV protection properties. It is observed that PEG acts as a good compatibilizer, facilitating better interfacial connection between CNF and HDPE matrix. The optimized composite with 0.15 wt.% CuO nanorods (H/C6/P4/Cu0.15) shows a fine morphology and strong interfacial connections between fillers and the matrix, as observed in FE‐SEM micrographs. This optimized composite exhibits improved thermal stability, higher thermal conductivity (0.0404 W.K−1.m−1), increased dielectric constant, reduced electrical volume resistivity (from 2.1 × 1015 to 2.1 × 106 Ω.cm), and lower optical band gap value (2.74 eV). Additionally, all prepared nanocomposites offer approximately 100% Ultraviolet Protection Factor (UPF) rating for UV protection. Highlights: The transformation of insulating HDPE into conducting HDPE composites.The effect of CuO nanorods was investigated in compatibilized HDPE composites.A percolation is achieved in the HDPE composite at 0.15 wt.% of CuO nanorods.PEG and CuO nanorods improved the multifunctional properties of the composite. [ABSTRACT FROM AUTHOR]

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. Highlights: 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]

Highlights The development of epoxy resin (EP) potting material with high thermal conductivity (TC) and excellent electrical insulating properties plays an important role in the development of drive motors to high specific power and high voltage. In this study, a simple preparation method is presented to solve the problem of low content filler settling and low TC of EP. Firstly, small‐sized perfluoroalkyltrimethoxysilane surface‐treated nanodiamond (ND) and large‐sized hydroxylated boron nitride (BN) were adsorbed together using hydrogen bonding to construct “Sesame Cookie”‐like structures. The heterostructure filler with different “sesame” contents were obtained by modulating the ND:BN ratio, and were filled into high‐temperature resistant AG70 EP at a fixed mass ratio of 20 wt.%. By surface treatment, the dispersibility of fillers in EP was improved, and the settling problem of low content fillers was solved. Finally, when the ratio of ND: BN is 1:2, the TC value of EP composite reached 0.94 W·m−1·K−1, which was 348% higher than pure EP, and the composite possessed good electrical insulating properties. In addition, the heat‐resistance temperature of the composite exceeded 200°C, which ensured the stable operation of the drive motor. This study presents new ideas for the exploitation of EP potting materials with high TC and excellent electrical insulating properties. Heterostructure filler is constructed using hydrogen bonding. Dispersion of the filler in the EP is improved by surface treatment. The TC value of the EP composite increased by 348%. The heat‐resistant temperature of the EP composite is more than 200°C. The EP composite has excellent insulating properties. [ABSTRACT FROM AUTHOR]

HIGHLIGHTS The influence of hexagonal boron nitride (hBN) nanosheet surface modification on epoxy nanocomposites' mechanical and thermal properties were investigated. An innovative approach was developed for synthesizing hBN nanosheets (hBNNs) via optimized ultrasonic‐assisted liquid‐phase exfoliation (UALPE), followed by functionalization with 3‐aminopropyltriethoxysilane (APTS) and polyethylene glycol (PEG600) for nanocomposite preparation. Compared to unmodified epoxy, nanocomposites containing 0.3 wt% of pristine hBNNs exhibited significant enhancements in flexural strength (125.28 MPa) and tensile strength (53.35 MPa), with respective increases of 40.57% and 43.23%. PEG‐hBNNs improved flexural and tensile strengths to 136.83 and 58.57 MPa, respectively. The most substantial enhancements were observed with APTS‐hBNNs, yielding flexural and tensile strengths of 174.13 and 63.53 MPa, reflecting increases of 95.37% and 70.50%, attributed to better interfacial interactions and a more effective crack deflection mechanism. Thermal stability analyses revealed superior performance of modified hBNNs epoxy nanocomposites, increasing 8.2°C and 6.3°C at 50 wt% degradation as compared to the unmodified system, owing to enhanced physical barrier properties. Structural and morphological analyses validated the successful exfoliation and modification of hBNNs. Predictive models utilizing machine and deep learning (DL) techniques, particularly DL with the adaptive moment estimation (ADAM) optimizer, effectively forecasted mechanical properties, achieving high R2 values. 0.3 wt% modified hBNNs epoxy nanocomposite showed the highest mechanical strength Improved thermal stability of epoxy nanocomposite by modification of hBNNs Improved crack deflection mechanism in the presence of surface‐modified hBNNs Deep learning with ADAM optimizer showed high R2 and low prediction loss [ABSTRACT FROM AUTHOR]

Highlights The fused filament fabrication (FFF) is an additive manufacturing process in which thermoplastic strands are deposited. Due to thermal fusion of the strands, the FFF can be characterized as a plastic welding process. The resulting weld seams are weak points in the component structure and, thus, determine the mechanical properties. Thereby, the weld seam quality is significantly influenced by the process temperatures. To estimate the mechanical properties, knowledge of the resulting weld seam quality is required. In the context of material development, the weld seam quality can also be used as a criterion for the basic evaluation of the processability. In the present study, the influence of particulate fillers on the weld seam quality of a thermoplastic polymer matrix is investigated. With regard to the material, the influences of the filler type and the filler volume fraction are considered. In terms of the process, the influence of the process temperatures on the weld seam quality is evaluated. The aim is the description of the resulting weld strength and the comparison to the base material strength by means of the welding factor. For this purpose, an existing method is applied and adapted with regard to process reliability and comparability. Test plan is determined on the basis of a thermal analysis Method adaptation enables faster and reliable specimen manufacturing Higher process temperatures lead to higher weld seam strengths Filled polymers show a significantly reduced weld seam strength Relationship between filler content and weld seam strength is shown [ABSTRACT FROM AUTHOR]

Due to its high thermal conductivity, graphene finds extensive application in thermal composite materials. However, akin to polymer composites containing other fillers, the thermal resistance at the interface between graphene and the polymer matrix substantially impedes heat conduction. Thus, functionalizing graphene becomes imperative to enhance its dispersibility in polymers. In this study, we synthesized the imidazolyl ionic liquid 1‐methyl‐3‐triethoxysilpropyl imidazole chloride ([MTESiPIM]Cl). Ionic liquid complexes supported by graphene (G) were synthesized via a simple ultrasonic stripping method by combining electrochemical graphene (G) with [MTESiPIM]Cl (Si‐IL@G). The Si‐IL@G/LLDPE composite was formed by blending Si‐IL@G into the linear low‐density polyethylene (LLDPE) matrix using a melt blending technique. Upon adding 5% Si‐IL@G, the tensile strength and bending modulus of Si‐IL@G/LLDPE composite reached 13.5 MPa and 348.2 MPa, respectively, marking an increase of 20.67% and 57.79% over pure LLDPE. The Si‐IL@G/LLDPE composite exhibited a thermal conductivity of 0.49 W·m−1·K−1, 96.0% higher than that of pure LLDPE. Given its outstanding thermal conductivity and mechanical properties, Si‐IL@G holds great potential in producing composites with high thermal conductivity. Highlights: An ionic liquid with siloxanyl groups was synthesized using microwave assistance.The ionic liquid was modified onto graphene sheets using ultrasonic techniques.The study examined how ionic liquid‐modified graphene affects LLDPE structure.The thermal conductivity and mechanical properties of LLDPE were enhanced. [ABSTRACT FROM AUTHOR]

The present study investigated the use of expanded perlite (e‐perlite) as a sustainable and cost‐effective filler for EPDM (ethylene propylene diene monomer) rubber composites. Various amounts of e‐perlite were incorporated into EPDM to assess its impact on the composite properties, such as curing characteristics, physical and mechanical properties, crosslink density, thermal conductivity, thermal stability, surface roughness, and contact angle. The composite with 15 phr of e‐perlite exhibited approximately 20% higher crosslink density and a 12% increase in hardness, while slight decreases were observed in elongation at break and tensile strength. The FE‐SEM (field emission‐scanning electron microscopy), atomic force microscopy, and contact angle analysis have been performed to investigate the surface morphology and the hydrophobicity. The thermal properties of the composites were assessed through thermogravimetric analysis, thermal aging tests, and thermal conductivity measurements. The results showed that e‐perlite significantly improved the aging resistance and the thermal stability. The composites with 15 phr e‐perlite exhibited a 21% reduction in thermal conductivity and enhanced thermal isolation properties compared to the EPDM composite without e‐perlite. This work demonstrated the potential utilization of e‐perlite in EPDM as a green sustainable filler to enhance the thermal insulation and the stability properties of the composites, which may have practical applications in automotive, aerospace, construction, and electronic industries. Highlights: E‐perlite enhances the thermal insulation property of EPDM rubber composites.Higher e‐perlite content increases composite hardness and crosslink density.The thermal conductivity of EPDM is reduced by increasing e‐perlite content.EPDM/e‐perlite exhibits improved thermal stability and aging resistance.Potential uses in automotive, aerospace, construction, and defense industries. [ABSTRACT FROM AUTHOR]

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. Highlights: 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]

Highlights The impact of carbon fiber (CF) composites sizing with graphene oxide (GO) to form brick‐and‐mortar structures on their mechanical properties and thermal conductivity has not been closely examined. This study systematically investigates the effect of GO sheet size on the interfacial properties and thermal conductivity of CF composites. Three sizes of GO—small (0.11 μm), medium (0.33 μm), and large (0.97 μm)—were used to modify CF surfaces via layer‐by‐layer self‐assembly, forming the brick‐and‐mortar structures. The mechanical properties were assessed through flexural tests, interlaminar shear strength (ILSS) tests and tensile tests, while thermal conductivity was measured using a thermal constant analyzer. The results revealed that medium‐sized GO (GO‐M) significantly enhanced the interfacial strength and toughness of the composites. This improvement is attributed to the orderly arrangement of GO‐M on the CF surface, which enhances stress transfer between the fiber and the matrix. In contrast, small‐sized GO (GO‐S) tended to scatter, resulting in less effective reinforcement, while large‐sized GO (GO‐L) exhibited stacking and agglomeration, limiting its reinforcement effectiveness. However, GO‐L provided the highest thermal conductivity due to the formation of continuous heat conduction pathways. These findings suggest that GO‐M offers a balanced improvement in mechanical properties, whereas GO‐L is more suitable for applications requiring high thermal conductivity. This work underscores the importance of selecting the appropriate GO sheet size to optimize the interfacial properties and thermal conductivity of CF composites, which is crucial for enhancing their performance in high‐end engineering applications, such as aerospace, automotive, and marine industries. Modification of CF composites by GO‐M sheets significantly improved toughness and strength. GO‐L sheets formed an effective heat transfer channel with the highest thermal conductivity. The study emphasized the critical role of selecting the appropriate GO sheet size to optimize the mechanical and thermal properties of CF composites. [ABSTRACT FROM AUTHOR]

Highlights Carbon black (CB) with different structural parameters together with graphene oxide were formed into uniformly dispersed filler network for enhancing the abrasion resistance of natural rubber/cis‐1,4‐polybutadiene rubber/trans‐1,4‐poly(isoprene‐butadiene) rubber blended composites. It showed that the CB structural parameters, such as specific surface area, surface activity and structural degree affected the formation of bound rubber. With the increase of bound rubber content, the homogeneity of filler network structure was improved and the filler‐rubber interaction was enhanced, resulting in a remarkable increase in the mechanical properties, thermal performance and abrasion resistance of the composites. Among the different types of CB, the composites filled with high‐structural‐degree CB of N134 had DIN wear volume as low as 76 mm3 and exhibited 19.5% higher abrasion resistance than N330. Wear surface observations and wear mechanism analyses showed that the increase in abrasion resistance was related to the improvement in tear resistance, hardness and thermal properties of the composites. Multiple linear regression analyses yielded that the structural degree in the structural parameters of CB had a significant correlation effect on the formation of bound rubber, and there was a strong linear relationship between the abrasion resistance of the composites and the content of bound rubber. Trans‐1,4‐poly(isoprene‐butadiene) rubber as compatibilizer for NR/BR blends. Synergistic enhancement of rubber using carbon black and graphene oxide. Carbon black with high structural degree promotes the formation of bound rubber. Described correlation between CB structural parameters and abrasion resistance of rubber. [ABSTRACT FROM AUTHOR]

Highlights Microfibrillated cellulose (MFC) was uniformly dispersed in high‐density polyethylene (HDPE) using a large amount of surfactant, and composites were prepared after removing the surfactant at different contents. The structural, morphological, thermal, and tensile properties of these composites were systematically investigated. The results demonstrated an asymptotic relationship between the amount of surfactant removed and the number of removal cycles. A negative linear correlation was observed between the surfactant content and the tensile strength, tensile modulus, and storage modulus at −20 °C of the composites, while a positive linear correlation was found with the loss modulus at −20 °C. Excessive surfactant adversely affected the dispersion of MFC, as well as the mechanical properties and thermal stability of the composites. However, when the surfactant content was below 2.8%, its impact on the composite properties was minimal, and the tensile strength, modulus, and thermal stability of the composites were significantly improved compared to neat HDPE. These findings indicate that surfactant pretreatment is an effective strategy for dispersing MFC in non‐polar polymers, and controlling the surfactant content in the final product can effectively tailor the properties of the resulting composites. Confirms the relationship between surfactant content and MFC/HDPE composite properties. Surfactant content showed an asymptotic relationship with removal cycles. Surfactant content and mechanical properties exhibited a negative linear correlation. Surfactant content and thermal stability exhibited a negative relationship. Surfactant content had minor impact when below 2.8%. [ABSTRACT FROM AUTHOR]

Highlights The bonding interface of carbon‐fiber‐reinforced polymer (CFRP)‐reinforced steel structure is a weak part, and nanomaterial‐modified adhesives are expected to improve its comprehensive performance. This paper investigates the micro‐modification mechanisms of nanomaterials on epoxy resin adhesives using molecular dynamics simulation method. It explores how the functionalized nano SiO2 and carbon nanotubes affects the thermal and mechanical properties of the epoxy resin adhesive. The models established using Materials Studio software include the pure epoxy resin adhesive model (EP) with varying degrees of crosslinking, the functionalized nano‐SiO2‐modified epoxy resin adhesive model (EP + SiO2/OH), the single‐walled carbon nanotube‐modified epoxy resin adhesive model (EP + SWNT), and the synergistic enhancements model of the epoxy resin adhesive with nano‐SiO2 and carbon nanotubes (EP + SWNT + SiO2/OH). Based on the aforementioned models, the Forcite module is used to calculate the free volume, glass transition temperature and mechanical properties of the adhesive. The results show that the degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. A high degree of crosslinking restricts the movement of the molecular chain, enhancing the strength of the epoxy resin adhesive. Furthermore, the trend of the mechanical and thermal properties of the four models remains constant with the rise of temperature, and the properties decrease most significantly in the range of the glass transition temperature. Moreover, the epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties. The epoxy resin adhesive reinforced with functionalized nano‐SiO2 and carbon nanotubes exhibits better properties compared to those with a single nanomaterial. The micro‐modification mechanism is revealed for nanomaterial modified epoxy resin adhesive. The degree of crosslinking effects significantly the mechanical performance of epoxy resin adhesive. The epoxy resin adhesive doped with nanomaterials exhibits varying degrees of enhancement in mechanical and thermal properties. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) was prepared from waste plastic using the two steps pyrolysis method and subsequently functionalized with ethylene diamine (EDA) to develop amino‐functionalized rGO (EDA‐rGO). To make the thermal and mechanical properties more proficient, EDA‐rGO was further incorporated as a nanofiller into a low‐density polyethylene (LDPE) matrix using the melt mixing method followed by hot‐pressing. A variety of analytical methods, such as FT‐IR, XRD, XPS, DSC, TGA, DMA, Raman spectroscopy, and HRTEM, were used to characterize the elements and morphology of rGO and EDA‐rGO. The results showed that the addition of 5 wt% EDA‐rGO to LDPE polymers significantly improved the mechanical and thermal properties, such as storage modulus by 62%, loss modulus by 67%, young's modulus by 123%, tensile strength by 79.83%, respectively. The thermal decomposition temperatures of 5%, 10% and 50% were increased by 14.01, 9.34, and 4.8°C, respectively. This study provides a feasible and ecologically sustainable way of repurposing plastic waste concurrently enhancing the properties of polymer composites. Highlights: Synthesis & functionalization of rGO from waste plastic using EDA.EDA‐rGO used as a nanofiller to fabricate LDPE polymer nanocomposites.EDA‐rGO enhanced the thermal stability of LDPE nanocomposites.The tensile strength & modulus of the LDPE composites are greatly improved.The storage, loss modulus, Tm and Tc enhanced by 62%, 67%, 4.4°C & 2.6°C. [ABSTRACT FROM AUTHOR]

The continuous updating and iteration of electronic devices brings about a significant accumulation of heat. It is urgent to enhance the thermal properties of polymer‐based composites to alleviate the heat dissipation problem in the microelectronics industry. In this paper, the hot drawing process was introduced to increase the crystallinity of ultra‐high molecular weight polyethylene (UHMWPE) fiber and improve its thermal conductivity. The ultra‐high molecular weight polyethylene fiber/epoxy resin (UHMWPE fiber/Epoxy) composites with high thermal conductivity were prepared by compositing UHMWPE fiber with epoxy resin under vacuum conditions. Due to the good crystallinity of the UHMWPE fiber (86%), an efficient thermal conduction path is provided for phonons in the axial direction along the fibers. The results show that the thermal conductivity of the composites reaches a maximum of 3.51 W/mK (in‐plane), which is 17.47 times higher than that of the epoxy resin (0.19 W/mK). The thermography pictures indicate that the composites have better heat transfer capacity with an increase in the draw ratio (λ). In addition, the composites also have the characteristics of low density and low electrical conductivity. These researches will provide a new idea for the preparation of all‐polymer composites with high thermal properties. Highlights: A hot drawing process was introduced to increase the crystallinity of UHMWPE fiber for improving thermal conductivity.High crystallinity facilitates the reduction of phonon scattering and the transmission of thermal energy by phonons.The obtained polymer composites exhibit an ultra‐high in‐plane thermal conductivity. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced epoxy resin matrix composite is one of the most important composite materials in the world. Many researchers have conducted a lot of research on epoxy resin matrix systems in recent years, mainly to improve the problem with the short curing time of the matrix system and epoxy resin's high viscosity. The final aim is to enhance various aspects of composites' performance and optimize the production process. A new type of water dispersed epoxy resin matrix system is investigated in this paper and the target is to optimize the mechanical, thermal, and electrical performances of the composites with the water dispersed epoxy resin matrix by varying different doping particles and different resin/catalyst ratios. Through a series of experiments, it is evident that varying the ratio of resin to catalyst in the matrix system will not significantly improve the mechanical as well as thermal properties of the composites. However, increasing the amount of catalyst in the matrix system can greatly improve the electrical properties of its composite samples. In addition to this, the addition of doping particles to the matrix systems has the effect of slightly enhancing the tensile modulus, thermal conductivity, and electrical conductivity of their composites. Highlights: A new water‐dispersed epoxy resin matrix system improves processing technology.Increasing amount of catalyst in the matrix system improves electrical resistivity.Adding particles to matrix systems has a slight effect on different properties. [ABSTRACT FROM AUTHOR]

Nylon nanocomposites were prepared by in‐situ ring‐opening polymerization to overcome the problem of poor properties due to the uneven dispersion of the nanoparticles by the traditional melt blending. This high‐performance polyamide 6 (PA6) nanocomposites with high dispersion and strong interface was prepared by grafting PA6 onto the surface of cellulose nanocrystals (CNC). The micromorphology, mechanical, crystalline and thermal properties of the composites were also investigated. Firstly, the hydroxyl group on the surface of CNC reacted with the para isocyanate of toluene diisocyanate (TDI), and the remaining ortho isocyanate was blocked by caprolactam to prepare CNC grafted with caprolactam (CNC‐g‐CL). Then CNC‐g‐CL was used as an activator to prepare cellulose nanocrystal grafted with polyamide 6 (CNC‐g‐PA6) composites by the ring‐opening polymerization of caprolactam on the CNC. The effects of different reaction temperatures, solvent amounts and molar ratios on the grafting rate of CNC‐g‐CL were investigated. The results showed that the highest grafting rate of CNC‐g‐CL with 66.7% was achieved at a reaction temperature of 45°C, 0.1 g/mL CNC in toluene, and a molar ratio of 6 for TDI/CNC. Further, different CNC‐g‐PA6 composites prepared from different CNC content and activator content were explored. For CNC‐g‐PA6 composites, CNC was uniformly dispersed in the PA6 matrix and had a good compatibility with the matrix. CNC exhibited significant reinforcement in the composites with a tensile strength of up to 108 MPa. In addition, the glass transition temperature of CNC‐g‐PA6 was increased to 92°C, which significantly improved the heat resistance of the new composites. Highlights: Effects of reaction condition of CNC and TDI on DSTDI and DSCL were studied.Effects of CNC and activator content on CNC‐g‐PA6 properties were studied.CNC is uniformly dispersed in PA6 with average particle size less than 1 micron.The nylon matrix was significantly strengthened by the addition of CNC.The addition of CNC significantly improved the heat resistance of the composites. [ABSTRACT FROM AUTHOR]

The development of innovative composite materials through the amalgamation of thermoplastic polyurethane (TPU) with bismuth sodium titanate (BNT) and carbon nanotube (CNT) fillers was investigated. Before the composite fabrication, the fillers' surfaces were treated to enhance their compatibility with the TPU matrix. Hybrid fillers of BNT and CNTs were fabricated by mixing the two types of filler particles through ball milling and subsequently annealing the mixture at 250°C. Melt‐blending and injection molding were utilized to synthesize the composites at 210°C processing temperature. The prepared composites showed significantly enhanced thermal conductivity, dielectric constant, thermal stability, and thermomechanical properties compared with the neat TPU matrix. For instance, the dielectric constant was enhanced by 340% upon the inclusion of 40 wt.% BNT and CNT fillers compared to the neat TPU matrix (40CBNT‐TPU has 13.2). In particular, the inclusion of BNT‐CNT particles in the TPU matrix improved the thermal conductivity of the TPU matrix by 1180% tremendously as compared to neat TPU (40CBNT‐TPU has 2.6 W/(m.K)). Highlights: Crystalline bismuth sodium titanate (BNT) is fabricated.Degradation of 8 wt.% of the IPDI‐treated BNT proves surface treatment.Dielectric constant (DC) improved by 340% compared to neat TPU.Thermal conductivity (TC) enhanced 11.4 times compared to neat TPU.Improvement in TC and DC will make it applicable in electronic materials. [ABSTRACT FROM AUTHOR]

The matrix cracking of carbon fiber reinforced epoxy resin based composites (CFRPs) at cryogenics (such as liquid nitrogen temperature) is a major issue affecting the normal operation of deep space and deep‐sea detectors, as microcracks caused by the thermal residual stress of both can reduce the structural integrity of the devices. In this work, we report an epoxy (EP) nanofiller CuO nanorods (CuO NRs) with negative thermal expansion properties at cryogenics. Experiments showed that CuO NRs can effectively inhibit the shrinkage of EP at cryogenics and improve the mechanical properties of EP at cryogenics. A temperature dependent prediction model for the tensile strength of EP/CuO NRs was proposed, and the predicted results were in good agreement with experimental results. Finally, through a combination of experiments and theory, it was demonstrated that the tensile strength of EP/CuO NRs at cryogenics is jointly enhanced by the enhancement effect of the nanomaterials and the axial compressive thermal residual stress between EP and CuO NRs. Highlights: Successfully prepared CuO nanorods with negative expansion properties at low temperatures, and found that they can effectively inhibit the shrinkage of epoxy resin at cryogenics.At cryogenics, the expansion of CuO nanorods enhances their interface effect with epoxy resin and improves the tensile strength of epoxy resin composites.The theory of tensile strength of epoxy resin at cryogenics was proposed for the first time. Theoretical analysis shows that the low temperature residual thermal stress between CuO nanorods and epoxy resin is the main factor to improve its tensile strength. [ABSTRACT FROM AUTHOR]

Poor interfacial adhesion between carbon fibers (CF) and the resin matrix has been a limiting factor in advancing the properties of composites. To address this challenge, this study employs the sizing method to coat carbon nanotubes (CNTs) and hexagonal boron nitride nanosheets (h‐BN) onto the CF surface. The 3D structures formed by strategic of combination 1D and 2D nanomaterials, markedly enhances the mechanical, thermal and frictional properties of CF composites. The results reveal a significant boost in the flexural strength, flexural modulus, interlaminar shear strength and interfacial shear strength of the prepared CF composites, registering increases of 53.96%, 60.41%, 55.58% and 55.35%, respectively. These advancements stem from the heightened surface reactivity and roughness of the fibers, facilitated by the synergistic interactions between CNTs and BN. Furthermore, the thermal conductivity of the composites exhibits a remarkable increase of 63.56%, attributed to the synergistic coupling between CF and BN, establishing an efficient thermal conductivity pathway within the composites. This research provides a highly effective approach for crafting high‐performance CF composites. Highlights: Construction of 3D network structures on CF surfaces by the sizing method.Synergistic coupling between BN and CNT enhances composite properties.Synergistic enhancement of friction and thermal properties of CF composites. [ABSTRACT FROM AUTHOR]

The high‐performance PPS/PEEK blends/composites were prepared with different mass ratios using polyphenylene sulphide (Solvey, Ryton®‐R‐4‐230 NA) and polyetherether ketone (Victrex, PEEK450 GL 30). All the blend samples had a single Tg, which revealed good compatibility between PPS and PEEK. The Tm was increased from 279.6 to 339.9°C due to addition of PEEK into PPS. Also, addition of PEEK into the blend increased the impact and tensile strength of the PPS material. The impact strength of the blend, PPS/PEEK (20/80) exhibited the maximum value of 113.64 J/m which was higher than that of PPS (70.66 J/m). The tensile strength of the blend was increased continuously with increasing the content of PEEK from 20 to 80 wt. % and reached the maximum value of 160.64 MPa. Additionally, milled carbon fiber (MCF) was also incorporated in order to obtain high strength PPS/PEEK blends/composites with good dielectric property. The dielectric performance of the composites was observed to increase with MCF content (in the frequency range 5.8 to 18 GHz). Highlights: This investigation relates to high‐performance PPS/PEEK blends and composites.Incorporation of milled carbon fiber resulted promising dielectric properties.Such composites may have Advanced structural EMI shielding electronics and/or aerospace applications. [ABSTRACT FROM AUTHOR]

Three‐dimensional molybdenum disulfide (MoS2) functionalized MWCNTs hybrid nanoparticles were synthesized using in‐situ hydrothermal reaction. Two types of hybrids, MoS2/MWCNTs‐1 and MoS2/MWCNTs‐2 with MWCNTs to MoS2 precursor weight ratios 1:2 and 1:1 respectively were prepared with varying degrees of hybridization and the effects of their incorporation on tensile strength and fracture toughness properties of epoxies were investigated. Epoxy/MoS2/MWCNTs‐2 nanocomposites showed exceptional mechanical properties due to their improved dispersion, constrained chain mobility and excellent interfacial interactions. MoS2/MWCNTs‐2 nanocomposites showed maximum improvement of tensile strength by 28.52% at 0.5 wt% nanofiller concentration and the highest improvements in fracture toughness by 172% at 0.2 wt% nanofiller concentration. The excellent enhancement of fracture toughness properties was due to the synergic effect of MoS2/MWCNTs hybrid nanoparticles due to the crack pinning and bifurcation properties of MoS2 nanoparticles along with the pull‐out and crack bridging mechanisms of MWCNTs as observed in morphological analysis of fractures nanocomposites. The incorporation of 0.2 wt% of MoS2/MWCNTs‐2 increased the degradation temperatures of epoxy from 591 to 796°C at 95% weight loss due to the improved physical barrier effect. Highlights: MoS2/MWCNTs nanoparticles were synthesized using in‐situ hydrothermal reaction0.5 wt% MoS2/MWCNTs‐2 incorporated epoxies showed highest tensile strength0.2 wt% MoS2/MWCNTs‐2 incorporated epoxy composites show improved K1c valueIncorporation of MoS2/MWCNTs improved the thermal stability of epoxySynergistic effect of nanocomposite due to crack pinning, bifurcation & bridging [ABSTRACT FROM AUTHOR]

Fluorine rubber (FKM) stands as a pivotal sealing material extensively employed in aerospace and nuclear industries. However, its efficacy will be seriously affected by ionizing radiation. Enhancing its radiation resistance becomes imperative to uphold the stability and safety of associated equipment. This study introduced hexagonal boron nitride (h‐BN) into the FKM as radioprotective fillers through mechanical blending. The interfacial interaction between matrix and h‐BN, the mechanical performances, thermal properties, and radiation stability of composites were systematically examined. Noteworthy findings highlight the presence of robust interaction forces between h‐BN and the matrix, leading to increased crosslink density and improved mechanical properties. The tensile strength of composite with 10 phr fillers (BN/FKM‐10) increased by 30% compared to that of pure FKM. Simultaneously, the introduction of h‐BN greatly enhanced thermal conductivity and radiation stability. The absorbed dose required to achieve a 50% reduction in elongation at break of BN/FKM‐10 surpassed that of FKM by 1.69 times. These results underscore the potential of incorporating h‐BN to simultaneously enhance the mechanical performance, thermal property, and radiation resistance of fluorine rubber. Highlights: The chemical interaction force between h‐BN and FKM was confirmed.FKM composites tensile strength was enhanced by h‐BN as an additive crosslinker.The incorporation of h‐BN improves FKM composites thermal conductivity.The radiation resistance of FKM composites has been improved with h‐BN. [ABSTRACT FROM AUTHOR]

Highlights Increasing miniaturization and integration of microelectronic devices have led to an unprecedented attention on heat dissipation and signal transmission of electronic equipment. However, the mostly used method to enhance the thermal conductivity of polymers by adding thermally conductive fillers usually results in the increase of dielectric constant (Dk). It was still challenging to synergistically achieve low Dk and high thermal conductivity of polymer‐matrix composites. Herein, hydroxylated boron nitride nanosheet (BNNS‐OH) with a high yield of 35.67% was prepared by the liquid ultrasonic exfoliation under the assistance of sodium cholate (SC), and grafted with (1H,1H,2H,2H‐perfluorodecyl) trimethoxy silane to prepare fluorinated boron nitride nanosheets (F‐BNNS), which can uniformly disperse in liquid silicone rubber (LSR) and reduce the Dk of LSR composites. The thermal conductivity of LSR composites with 20 wt% F‐BNNS reached 0.489 W·m−1·K−1, showing an increase of 307.35% in comparison with pure LSR (0.12 W·m−1·K−1). Meantime, the Dk of as‐obtained LSR/F‐BNNS (20 wt%) composites is reduced from 3.4 to 2.6, and the dielectric loss (Df) is less than 0.012. The facile and rational design of fluorinated BNNS offers a new insight for the high‐end electronic packaging materials. A new method of exfoliation and fluorinated treatment of h‐BN was proposed. The LSR composites achieved an ultralow Dk of 2.63 via fluorinated BNNS. Thermal conductivity of LSR composites increased by 307.35% than pure LSR. [ABSTRACT FROM AUTHOR]

Highlights Thermal expansion of materials is a critical factor influencing their dimensional stability. This study explores the regulation of thermal expansion in composite materials through the incorporation of carbon fibers and zirconium tungstate particles. The influence of fiber length on the thermal expansion behavior of these composites was investigated. The investigation reveal that the variation in the relative elongation ratio (dl/L0) of the carbon fiber‐reinforced zirconium tungstate composites is nonlinear, characterized by an initial increase, subsequent decrease, and a final resurgence. Notably, an increase in fiber length results in a mitigated rate of increase in the (dl/L0) ratio. Furthermore, composites fabricated with shorter fibers exhibit a higher coefficient of thermal expansion (CTE). Upon elevating the temperature to 250°C, the CTE for composites reinforced with 100 and 500 mesh carbon fibers escalate to 24.5 × 10−6/K and 74.6 × 10−6/K, respectively. These values represent an 8% and 116% enhancement relative to those measured at 50°C. The thermal expansion properties are improved by adding carbon fiber and ZrW2O8 nanoparticles. Utilizing fiber lengths ranging from 100 to 500 mesh effectively diminishes the CTE. The Cf‐ZrW2O8/9621 composite exhibits non‐linear behavior in its dl/L0 ratio. Within the range, longer fibers are more beneficial for reducing the CTE. [ABSTRACT FROM AUTHOR]

Highlights To improve the subpar lubricating performance of epoxy resin, this paper presents the preparation of a novel bimetallic phyllosilicate featuring a distinctive rice‐granular morphology, which incorporates nickel and iron metal cations through a facile hydrothermal process. These phyllosilicates were then integrated into the epoxy matrix to form composites. A comprehensive analysis of the target product validates the rationality of the synthesis strategy for the as‐prepared rice‐granular bimetallic nickel/iron phyllosilicate, demonstrating a homogeneous hierarchical structure with numerous tiny nanosheets of nickel/iron phyllosilicate grown in situ on the flat surfaces of the rice‐granular metal–organic frameworks. An adequate addition of nickel/iron phyllosilicates allows for excellent dispersion within the matrix and establishes strongly bonded interfaces, steadily increasing the elastic modulus and hardness. Notably, the average friction coefficients decrease from 0.515 for the pure resin to 0.450 for the composites when the filler content reaches 7%, indicating a significant solid lubrication effect. In contrast, adding just 1% nickel/iron phyllosilicate moderately improves wear resistance, elongation at break, and tensile strength. Furthermore, it was found that as the filler content increased, the weight loss rate was reduced by approximately 43.8%, while the residual char increased by 74.2%, significantly enhancing the thermal stability of epoxy composites at high temperatures. This study offers a promising approach to preparing self‐lubricated epoxy composites with favorable mechanical and thermal properties. NiFePS was successfully synthesized via a facile two‐step self‐polymerization. Excellent mechanical properties of composites could be achieved with low content of NiFePS. The friction coefficient and wear rate were lowered remarkably. The friction mechanism was solid lubrication. [ABSTRACT FROM AUTHOR]

Highlights This study investigated the effect of multi‐walled carbon nanotubes (MWCNTs) and reclaimed gypsum of varying contents on the mechanical properties and thermal stability of polypropylene (PP) composite materials. The results indicated that the incorporation of reclaimed gypsum and MWCNTs powder into PP composites could enhance the tensile strength, impact strength, and bending modulus of PP to a certain extent. The above properties of AGY/MWCNTs/PP composites were increased by 14.6%, 131.8%, and 36.2%, respectively, with the impact properties being significantly affected. Univariate analysis of variance revealed that MWCNTs powder and recycled gypsum exerted a significant impact on the mechanical properties of polypropylene composites. Moreover, the initial weight loss temperature of AGY/MWCNTs/PP demonstrated a notable increase, from 318.71 to 398.48°C, while the maximum weight loss temperature exhibited a comparable rise, from 406.85 to 461.54°C. The impact performance and thermal stability of polypropylene composite materials have been demonstrably augmented. A synergistic effect between reclaimed gypsum and multi‐walled carbon nanotubes in the reinforcement of polypropylene composites was demonstrated. This provides a theoretical framework and practical guidance for the design and preparation of high‐performance and recyclable polymer composites. [ABSTRACT FROM AUTHOR]

Highlights Nowadays, non‐timber sources are of greater interest as they avoid deforestation and the pollution which occurs with cellulose obtention. An emerging alternative is using weeds such as windmill grass (Chloris spp.) to isolate cellulose since the plant grows in large quantities near crops or landfills used for farming. The present study aims to explore windmill grass as an alternative source of cellulose for applications as reinforcement in biopolymeric matrices. Treatment was conducted using the peroxyformic pulping method, varying the formic acid (FA) and hydrogen peroxide (HP) concentration to obtain an optimum cellulose extraction condition. The isolated celluloses were analyzed for chemical composition, yield, chemical functionality, crystallinity, and morphology. The optimum pulping condition (FA = 87.5%, HP = 3%) shows the gradual removal of non‐cellulosic components by microscopy. X‐ray diffraction analysis revealed a high crystallinity index (89.63%) with a characteristic cellulose type I pattern. To evaluate the reinforced effect of Chloris spp. celluloses, film formulations were made using sweet potato starch, glycerol, and cellulose at different concentrations (2.5, 5.0, and 7.5% w/w). The films' mechanical, physicochemical, and thermal properties were measured, and results indicate that adding cellulose fibers significantly improves these properties of sweet potato starch films, revealing further applications and non‐wood windmill grass added value with potential applications in the packaging sector. Windmill grass (Chloris spp.) is presented as a non‐wood source of cellulose. The peroxyformic method is reported as a less polluting cellulose extraction process. Optimal cellulose pulp presents enhanced physicochemical properties after bleaching. Cellulose‐reinforced sweet potato starch films exhibit a stable biopolymeric matrix. The films produced show enhanced water barrier and mechanical/thermal properties. [ABSTRACT FROM AUTHOR]

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]

The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is important but is still elusive. Here, we illuminate this issue by investigating the role of four silane coupling agents in thermal conductivity for epoxy resin/Al2O3 composites. The results show that 3‐glycidoxypropyltrimethoxysilane (KH560) is the best silane coupling agent to modify Al2O3, resulting in the lowest viscosity and the highest thermal conductivity of the epoxy resin/Al2O3‐KH560 composite compared with alternative systems. This is attributed to the strong interfacial interaction between Al2O3‐KH560 and epoxy resin, as confirmed by the Fowkes model and broadband dielectric spectroscopy. The interfacial thermal resistance between the epoxy resin and Al2O3 is also quantitatively measured via a photothermal radiometry technique. The epoxy resin/Al2O3‐KH560 also has the lowest interfacial thermal resistance (1.50 ± 0.02 × 10−6 m2 K W−1), compared with the other three systems. This study advances the understanding of the relationship between interfacial structure and thermal conductivity in polymer composites. Highlights: The relationship between interfacial structure and thermal conductivity in epoxy resin/Al2O3 composite is understood.The interfacial structure is characterized by broadband dielectric spectroscopy.The interfacial thermal resistance is quantitatively measured via a photothermal radiometry technique. [ABSTRACT FROM AUTHOR]

Highlights In this electronic era, there is a demand to switch from conventional polymers to conducting biopolymers. We developed conducting biopolymer nanocomposites of cashew gum (CG) and polypyrrole (PPy) with zinc oxide (ZnO) nanofillers [CG/PPy/ZnO] via in‐situ oxidative polymerization using a sustainable solvent. These nanocomposites were characterized using Fourier‐transform infrared spectroscopy (FTIR), UV–visible spectroscopy, field emission scanning electron microscope (FE‐SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The FTIR signal at 855 cm−1 confirms the successful inclusion of ZnO nanofillers into the biopolymer. UV–vis absorption of the blend nanocomposite increases with the nanoparticle doses. Among the various blend nanocomposites, the least bandgap energy was observed for 7 wt% ZnO loading. FE‐SEM revealed homogeneous dispersion of ZnO nanofillers in the CG/PPy blend at 7 wt% ZnO. TGA and DSC demonstrated that the CG/PPy/ZnO nanocomposites have better thermal stability and glass transition temperature than the pure polymer blend, indicating enhanced thermal properties. The CG/PPy/7 wt% ZnO showed the highest conductivity, 4.62 times greater than the pristine blend at 100 Hz. Dielectric constant, activation energy, AC conductivity and dielectric loss measurements demonstrated that the nanocomposites outperformed the pure polymer blend. Complex impedance analysis revealed increased impedance with rising temperature. Overall, CG/PPy/ZnO nanocomposites exhibit superior optical, morphological, thermal, electrical, and dielectric properties, making them promising for energy storage and optoelectronic applications. Ecofriendly synthesis of CG/PPy/ZnO nanocomposites Enhancement in optical, structural, and thermal properties of CG/PPy/ZnO Dielectric properties and temperature‐dependent AC conductivity are summarized. Blend nanocomposite shows higher AC conductivity and dielectric constant CG/PPy/ZnO nanocomposites are suitable for energy storage applications [ABSTRACT FROM AUTHOR]

Highlights By applying an electric field, the thermal conductivity(λ) of composites can be enhanced through the induced orientation of high λ fillers within the matrix. As far as the DC electric field is concerned, the pattern of the electric field application time on the λ of the composites is not clear. In this work, a 400 V/mm DC electric field was selected to prompt the alignment of boron nitride (h‐BN) within the epoxy resin (EP) matrix, with an in‐depth analysis of how the timing of the electric field application influences the λ of the composites. Results demonstrate that the λ of h‐BN/EP composites exhibits a pattern of increasing, decreasing, then increasing and finally stabilizing when the electric field application time is 0–480 min. When the electric field was applied for 20 min, the composites exhibited a maximum λ of 0.544 W/(m K), a value that is 3.88 times of pure EP, and 2.32 times of that of the composites without electric field under the same filling content. In addition, the composite exhibits an AC breakdown field strength (Eb) that is slightly elevated compared to the pure EP. Boron nitride (h‐BN) was successfully oriented in epoxy resin (EP) matrix by electric field induction. λ of the composite is proportional to orientation Angle of h‐BN in the matrix. λ of composite can be increased by electric field induced fillers orientation. Electric field induction does not damage the insulation properties of composite. The excellent in‐plane λ and insulation properties of h‐BN are fully utilized. [ABSTRACT FROM AUTHOR]

Highlights Acrylonitrile butadiene styrene (ABS) polymer has received considerable attention due to its high versatility for applications, including additive manufacturing. However, its electrical and thermal transport properties limit its application potential. One route to enhance electrical and thermal conductivities is the development of ABS‐based composites by using carbonaceous fillers, which have exceptional mechanical properties and remarkable functional properties. Here, we testing the presence of carbonaceous fillers with different dimensionalities on the electrical and thermal conductivity of ABS composites. In particular, one dimensional (1D) carbon nanotubes (CNT), two dimensional (2D) reduced graphene oxide (rGO), and three dimensional (3D) carbon black (CB) have been used to develop ABS‐based composites with different filler contents. A similar trend exist for the electrical and thermal conductivity results, where the highest conductivity values (electrical conductivity 0.0305 S·cm−1 and thermal conductivity 0.56 W·mK−1) being achieved for ABS‐based composites with 2D rGO filler, highlighting the relevance of specific characteristics of the 2D type filler. In addition, electromagnetic interference (EMI) shielding effectiveness (SE) of the ABS‐based composites containing rGO was superior to other 1D and 3D fillers. The stated correlation between electrical and thermal properties and their dependence on carbonaceous filler dimensionality are essential to be taken into account for properly tailoring functional properties of ABS‐based composites. Carbonaceous fillers are used to tailor several properties of ABS composites Significant differences are established between filler type or content Electrical percolation threshold strongly depends on the dimensionally 2D rGO more effective to improve electrical/thermal conductivities 1D CNT and 2D rGO fillers exhibit best EMI shielding properties [ABSTRACT FROM AUTHOR]

This work reports polymer/metal double‐shell microcapsules with polysulfone (PSF) and copper as walls for application in self‐lubricating polymer. First, polyalphaolefin 40 (PAO40) was selected as lubricant oil, and PAO@PSF single shell microcapsules were prepared. A critical issue for the formation of copper layer is the sensitization of PSF shell, which can affect not only the adhesion between PSF shell and copper layer, but also the density of copper layer. The sensitization conditions were discussed in detail, and the corresponding effect on the formation of copper layer was evaluated. PAO@PSF/Cu microcapsules obtained under optimal sensitization condition were characterized by scanning electron microscopy (SEM), thermogravimetric analyzer (TGA), x‐ray energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR). A uniform and compact copper layer improved the thermal properties of microcapsules. PSF/Cu microcapsules maintained relatively complete spherical shape when were heated to 300°C, while the PSF microcapsule softened and deformed at 200°C. The self‐lubricating polyamide 6(PA6) composites containing PAO@PSF/Cu microcapsules were fabricated at 230°C, microcapsules maintained complete structure and uniform distributed in the polymer matrix. Coefficient of friction (COF) and wear rate of PA6 composites were tested under different friction conditions. Compared with pure PA6, 15 wt.% PAO@PSF/Cu microcapsules could reduce the COF by 79.5%, and the wear rate was decreased by 98.3% under 300 rpm sliding speed and 50 N friction load. Highlights: PSF/Cu double‐shell oil‐loaded microcapsules were designed and prepared.The copper layer effectively improved the thermal properties of microcapsules.The self‐lubricating PA6 composite exhibited excellent tribological properties. [ABSTRACT FROM AUTHOR]

Highlights A fluorinated polyimide (PI‐FTD) was synthesized for preparing a thermally conductive PI matrix and composites. Additionally, surface‐treated boron nitride (BN) was incorporated into the PI‐FTD via the solution casting method to form efficient heat paths along the through‐plane direction. The resultant composite demonstrated remarkable characteristics, including an impressive through‐plane thermal conductivity of 3.6 W mK−1, a substantial tensile strength of 69.4 MPa, and excellent thermal stability. When this composite was applied to light‐emitting diodes, it effectively managed heat, reducing the operating temperature by 29°C. The PI‐FTD/BN‐OH composites can potentially improve thermal management in electronic devices. A novel fluorinated polyimide (PI‐FTD) was fabricated. Introducing CF3 functionalities in the PI‐FTD provides high thermal stability. BN‐OH reinforced the thermal and mechanical properties of the composites. The PI‐FTD/BN‐OH composites achieved excellent thermal management. [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]

Highlights High temperature shape memory polymers (HT‐SMPs) have great utilization in self‐deployable hinges/morphing structures for space/aerospace, and high‐temperature sensors/actuators for electronics. However, HT‐SMPs have many drawbacks, such as low stiffness, strength, thermal stability, and dynamic mechanical properties. This work aims at improving these properties of highly utilized space grade HT‐SMP, PEKK (polyether ketone ketone), by reinforcing it with low‐cost carbon fibers (CFs), and developing its composite via additive manufacturing. The additively manufactured CF/PEKK composites are annealed at 200 °C (CF/PEKK‐A200) and 250 °C (CF/PEKK‐A250), and for the first time, investigated for shape memory effect (SME). The shape fixity and the shape recovery of the CF/PEKK‐UNA (un‐annealed), CF/PEKK‐A200, and CF/PEKK‐A250 are noted to be 95.97%, 88.95%, and 86.40%, and 88.70%, 92.70%, and 95.19%, respectively with a significant weight saving potential of ⁓21%. Dispersion of CFs in PEKK and suitability of processing parameters (blending, extrusion, and 3D printing) are confirmed through scanning electron microscopy (SEM). Thermal degradation temperature (Td$$ {T}_d $$) of the printed CF/PEKK composite (⁓568 °C) is found to be ⁓3.5% higher than PEKK (⁓549 °C). CF/PEKK‐A250 exhibited the highest storage modulus (4438.23 MPa), ~158% higher than PEKK (1722.3 MPa), while CF/PEKK‐A200 demonstrated the highest tensile modulus (10.9 GPa), which is 138.5% higher than PEKK (4.57 GPa) and 312.88% higher than CF/PEKK‐UNA (2.64 GPa). Moreover, CF/PEKK‐A200 exhibited 237.46%, 138.51%, 127.08%, 61.48%, 32.93%, and 50.35% higher tensile modulus than PEEK, PEKK, PEK, CF/PEK, CF/PEEK, and CF/PEKK composites, respectively, showing great potential to replace them. Printed CF/PEKK composites are investigated for shape memory behavior. The printed composites exhibited outstanding shape memory properties. Printed‐A200 exhibited 138.51% enhanced tensile modulus than pure PEKK. Also, the printed‐A200 showed 313% enhanced modulus than printed‐UNA. Td$$ {T}_d $$ (568 °C) of the printed composites is found ⁓4% greater than pure PEKK. [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]

Highlights This study explores the development of nanocomposites by incorporating multi‐walled carbon nanotubes (MWCNT), titanium nitride (TiN), and cubic boron nitride (c‐BN) nano powders into photo‐polymer epoxy resins for use in Stereolithography (SLA) additive manufacturing. Mechanical and thermal properties were systematically investigated to assess their performance. Initially, MWCNT, TiN, and c‐BN nano powders were homogeneously mixed with the resin to ensure uniformity. The resulting mixtures were then processed using SLA technology to evaluate production quality and material performance. The study revealed significant improvements in mechanical and thermal properties compared to pure resin, aligning with previous research outcomes. Specifically, the incorporation of MWCNT led to a notable enhancement in thermal conductivity, showing an increase of 24.21% as the thermal conductivity coefficient increased from 0.19 to 2.36 W/m·k. On the other hand, c‐BN significantly boosted mechanical strength, resulting in a substantial 20.45% increase as the shore D hardness went from 88.53 to 106.64. These findings highlight the promising potential of nanocomposites across various industries including electronics, aerospace, automotive, construction, medical devices, and manufacturing. Developed nanocomposites with MWCNT, TiN, and c‐BN in SLA resin. c‐BN increased hardness by 20.45%, proving its effectiveness in composites. MWCNT enhanced thermal conductivity by 24.21%, boosting material performance. Pioneering use of TiN and c‐BN in SLA, addressing gaps in existing research. Applications span electronics, aerospace, automotive and medical devices. [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]

Highlights Increasing the thermal stability and thermal conductivity of polydimethylsiloxane (PDMS) is a crucial issue for thermal applications. This paper focuses on enhancing PDMS's thermal and structural properties by incorporating nanocomposite into the PDMS matrix. An investigation of the impact of rGO‐CaCO3 nanocomposite on the thermal and structural properties of PDMS was performed using Field Emission Scanning Electron Microscopy (FESEM), X‐ray diffraction (XRD), the thermogravimetric analysis and differential thermal analysis (TGA‐DTA), and thermal analyzer tests. It was observed that PDMS doped with rGO‐CaCO3 nanocomposite shows better thermal stability, thermal conductivity, and higher crystallinity. The thermal stability was enhanced significantly by adding a 5% rGO‐CaCO3 nanocomposite, and the initial and end degradation temperatures rose to 492°C and 605°C, respectively. The thermal conductivity of pure PDMS is approximately 0.17 W/mK, whereas a conductive elastomer filled with 5% rGO‐CaCO3 nanocomposite exhibits a thermal conductivity of 0.44 W/mK at a temperature of 20°C. In contrast, the thermal diffusivity is enhanced from 0.13 mm2/s to 0.366 mm2/s. Additionally, the Fourier Transform Infra‐Red (FTIR) spectrum at 1411 cm−1 becomes sharp and noisy, and an additional peak arises at 1398 cm−1, corresponding to the vibrational rocking of the CC bond and COC bond in CaCO3 and rGO. The manuscript focuses on the development of conductive elastomer by incorporating rGO‐CaCO3 doped and its effect on the morphology, structure, and thermal properties of PDMS. The variation in peak intensity observed in XRD attributed to disparities in the crystalline structure of PDMS due to the inclusion of nanocomposite. The thermal degradation range is observed to shift toward the upper end. The degradation temperature at the beginning and end of the process is observed to move to 492°C and 605°C, respectively, upon introducing a 5% rGO‐CaCO3 nanocomposite. The addition of 5% rGO‐CaCO3 filled conductive elastomers shows a significant improvement of approximately 2.6 times in heat conductivity than bare PDMS. [ABSTRACT FROM AUTHOR]

In this study, the effects of polypropylene (PP) composites produced by adding 10% old newspaper fibers (ONP), 5% microcrystalline cellulose (MCC), 3% polypropylene carbonate (PPC), and waste toner from 1% to 4% on the mechanical properties, physical properties, morphological, and thermal properties were investigated. According to the FTIR‐ATR and SEM‐EDS analysis results, it was determined that a significant part of the waste toner used in the study consisted of polystyrene co‐acrylate, and the remaining part consisted of carbon black and trace amounts of silicate. In the research, it was determined that the flexural and tensile strengths of MCC/ONP/PP composites containing 1% waste toner and 3% PPC increased by 13% and 46%, respectively, compared to the control sample. Additionally, the samples with the lowest water absorption values were measured in composites containing 1% waste toner and 3% PPC. The highest crystallinity value (50.75%) was obtained with the use of 1% waste toner and 3% PPC in MCC/ONP/PP composites. However, with waste toner usage above 1%, the mechanical, thermal properties, and water absorption rate have slightly decreased. As a result of the study, it was concluded that up to 1% waste toner with 3% PPC can be used successfully in MCC/ONP/PP composites. [ABSTRACT FROM AUTHOR]

To further increasing the toughness performance of thermoset resins without sacrificing their other properties is still a challenge task. In this study, the soft core–soft shell nanoparticles based on polydopamine‐modified cellulose nanocrystals (P‐CNC) were synthesized and seamlessly integrated with Bisphenol A‐aniline benzoxazine (BA‐a). Notably, the results underscore the remarkable impact of a mere 0.2 wt% of P‐CNC on BA‐a, boosting the impact strength of the modified system to 19.5 kJ/m2. This achievement represents a substantial 140.7% increase compared with pure polybenzoxazine. Moreover, the flexural strength reaches 133.4 MPa, surpassing pure polybenzoxazine by 16.2%. And the modified system exhibits a 10% weight loss temperature (Td10) at 321.7°C, accompanied by a char yield of 27.6%. This holistic approach results in a notable enhancement of the toughness performance while concurrently maintaining the flexural strength and the thermal stability of the modified system. Consequently, the integration of soft core–soft shell nanoparticles emerges as a promising strategy for enhancing thermoset resin properties without undermining their existing exceptional attributes. Highlights: The core–shell nanoparticles were made by dopamine and cellulose nanocrystals.The core–shell nanoparticles can enhance the toughness of polybenzoxazine.Nanoparticle‐matrix interactions and deformation led to improved properties. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) fiberwebs and multi‐ply assemblies of nettle woven reinforcement are used to develop a series of nettle/PLA biocomposites with different reinforcement orientations. The tensile strength, flexural strength, impact strength, and thermal properties of the biocomposites are found to improve by piling nettle fabrics and are also found to depend strongly on the piling architecture and the test direction. It is possible to obtain a biocomposite with higher degrees of isotropy and enhanced mechanical properties by using cross‐ply laminates. The three‐layered woven fabric reinforced PLA biocomposite with a reinforcement orientation 0°/45°/90° shows the best results among all the biocomposites developed in this study. The tensile strength, Young's (tensile) modulus, flexural strength, impact strength, storage modulus, and loss modulus of the biocomposite are found as 55.25 MPa, 6.30 GPa, 85.83 MPa, 63.74 J/m2, 10.08 GPa, and 0.75 GPa, respectively. In this biocomposite, a fair adhesion between matrix and reinforcement is noticed, and this is justified by retardation of crack propagation as well as by substantial energy dissipation. The thermal stability of the biocomposite does not get effected much, but the percent crystallinity increases by 25.84%. The degradation kinetics and the activation energy of the biocomposite are determined through a differential fitting of Arrhenius model. The soil burial test reveals 15.06% of weight loss and 50.56% strength loss for this biocomposite just after 20 days of burial under soil. Highlights: Multi‐ply architecture of woven fabric reinforcement in nettle/PLA biocomposites.Nearly isotropic biocomposite through angle‐ply orientation of reinforcement.Biocomposite with remarkable static and dynamic mechanical properties.Augmented kinetic parameters through model fitting of Arrhenius equation.Biocomposite with excellent thermo‐recyclability and biodegradability. [ABSTRACT FROM AUTHOR]

A series of halloysite nanotube‐silica (HNTs‐SiO2) nanocomposite fillers were prepared by in‐situ assembly, and a reinforced SiO2/SR composite was obtained by filling them into silicone rubber (SR). The morphology and structural characterization of HNTs‐SiO2 and HNTs‐SiO2/SR and the properties of the HNTs‐SiO2/SR were studied. As a result, the small particle size SiO2 was firmly anchored onto the HNTs surface, and the obtained HNTs‐SiO2 nanofillers were uniformly dispersed in SR. At a 30 phr fixed filler loading, the weakest filler network and the best filler dispersion were obtained when HNTs content in HNTs‐SiO2 was 5%. This resulted in a maximum tensile strength obtained of 6.2 MPa, 1.55 times that of SiO2/SR with the same filler loading, and a maximum elongation at break of 418%, 1.67 times that of the SiO2/SR with the same filler loading, and at the same time the tearing strength and hardness are also improved. Furthermore, the silicone rubber also showed improved thermal stability, with an initial degradation temperature increase of 30°C under a nitrogen atmosphere. Highlights: HNTs–SiO2 nanocomposites were successfully prepared by the self‐assembly method and used as fillers in SR as a new type of reinforcing material.The 1D HNTs act as a barrier to prevent SiO2 aggregation and improved fillers dispersion.The elongation at break and tensile strength of 5% HNTs‐SiO2/SR are 67% and 55% higher than those of SiO2/SR, respectively.The silicone rubber also showed improved thermal stability. [ABSTRACT FROM AUTHOR]

This study investigates the effect of positive temperature coefficient (PTC) fillers, i.e., barium strontium titanate (BST‐60) and nano hexagonal boron nitride (h‐BN) fillers, on thermal and dielectric insulation properties of epoxy (EP). The electrical resistivity, DC breakdown strength, space charge, thermal conductivity, thermogravimetric analysis, and glass transition temperature (Tg) of EP composites were measured. Results indicate that, below curie temperature, the EP composites containing 0.5 and 1 wt% of BST and 5 wt% of h‐BN have superior electrical resistivity, breakdown strength, and thermal conductivity. However, above curie temperature, the EP composites containing 2 and 2.5 wt% of BST and 5 wt% of h‐BN have superior insulation properties than the pure EP and other composites. While the thermal properties of EP improve with an increase in h‐BN loading to 10 wt%, its dielectric properties are slightly compromised due to the presence of tiny defects in the composite material. It is hypothesized that the BST‐60 suppresses the negative temperature coefficient effect (NTC) of EP by regulating the electrical resistivity above the curie point, whereas nano h‐BN enhances the thermal conductivity of EP by constructing a heat dissipation path. The proposed mechanism for charge dynamics along with heat conduction‐dissipation explains the fillers' behavior at different temperatures. Highlights: Analysis of epoxy composites with polydopamine‐modified BST and h‐BN fillers.PTC fillers are used to mitigate the negative temperature effect of epoxy.Optimal fillers wt% improves dielectric and thermal properties.This study shows that optimized epoxy composites can be used for packaging. [ABSTRACT FROM AUTHOR]

The use of hybrid reinforcement in polymer composites has been getting attention due to its potential for weight and cost reduction while achieving improved design flexibility for mechanical and thermal properties. In this study, an interply hybridization of epoxy laminates was performed using layers of solid and hollow glass fibers. The structural and thermal performance of the resulting hybrid vascular composites was investigated. All composite parts were manufactured using vacuum‐assisted resin transfer molding (VARTM), following an interply hybridization plan for the stacking sequence of hollow and solid fiber layers. An expected decrease in flexural properties and thermal conductivity was observed for the laminates with completely hollow fibers. On the other hand, hybridization had a positive effect on the laminate properties. It was shown that hybrid vascular composites could be manufactured without a significant reduction in mechanical and thermal performance by a judicious hybridization plan. The optimum hybridization of the laminate achieved a 3.1% increase in the specific flexural strength and a 5.3% decrease in thermal conductivity while containing a vascular network that can be used for active thermal control. Highlights: A vascular interply composite structure consisting of hollow and solid fibers was manufactured and characterized for the first time.The I4 composite, vascularized through the middle layers of the laminate, has almost as much flexural strength as solid composite and much more specific flexural strength.The thermal conductivity of the I4 composite is almost as much as that of the solid composite.Functional composites for thermal management and smart applications can be manufactured using hollow fibers without sacrificing flexural strength and thermal conductivity with interply vascularization. [ABSTRACT FROM AUTHOR]