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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 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 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 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 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]

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]

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]

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]

In this paper, polysulfonamide‐based composite materials (SCF/PSAf composite) reinforced by the short carbon fiber were prepared. The mechanical properties and thermal stability of SCF/PSAf composite were characterized experimentally and compared with those of polysulfonamide‐based single‐polymer composites (PSA SPCs). Results showed that SCF/PSAf composites exhibit higher thermal stability due to the excellent thermal stability of SCFs. Furthermore, the additional short carbon fibers also considerably enhance the flexure strength of PSA SPCs due to the strong interfacial bonding between SCF and PSAf. The properties and understanding of SCF/PSAf composite obtained in this work can benefit further applications of this novel composite material. Highlights: SCF/PSAf composites are prepared by hot compression, and the adhesion between the PSA matrix and SCF is good.The flexural strength of the SCF/PSAf composite is about 2.5 times higher than that of PSA SPCs.The storage modulus of SCF/PSAf composites is about 3.5 times higher than that of PSA SPCs.The addition of short carbon fibers helps to improve the thermal properties of SCF/PSAf composites.SCF/PSAf composite has a stronger ability to resist deformation and a higher operating temperature than the PSA SPCs do. [ABSTRACT FROM AUTHOR]

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

Composites with excellent flame retardant and mechanical properties are in high demand in the aerospace and various industrial fields. Glass fiber (GF) reinforced polyimide (PI) composites (GFRPCs) were fabricated using a simple ball milling and hot pressing technique. The effect of GF content on the thermal stability, mechanical and flame retardant properties of composites has been systematically studied. The Rockwell hardness of GFRPCs increase with increasing GF content, while the compressive strength, impact strength and flexural strength initially show an increase followed by a decrease due to the excellent dispersibility of the fillers and the strong interfacial interaction between the one‐dimensional GF and PI matrix. Thermogravimetric analysis results show that the addition of GF with very low thermal conductivity and excellent temperature resistance can effectively improve the thermal stability of PI. Adding GF into PI can obviously improve the limiting oxygen index value. Moreover, as the GF content increased, the time to ignition of the composites prolonged while total heat release decreased. These findings suggest a viable solution for enhancing both the flame retardance and mechanical properties of PI‐based composites. Highlights: GFRPCs with high GF content fabricated via ball milling‐hot pressing method.Silane modified GF obviously improves the thermal stability of PI matrix.GFRPCs‐28 exhibits superior mechanical properties.An increases in time to ignition (TTI) and mass residual rate (MRR) of the GFRPCs was observed on adding GF. [ABSTRACT FROM AUTHOR]

This study reports how hybrid nano‐filler can enhance the tensile strength, electrical properties and thermal stabilization of PAN (polyacrylonitrile) nanocomposite films. The nano‐fillers used are graphene oxide (GO), single‐wall carbon nanotubes (SWCNT), and a hybrid of both. The combination of both nano‐fillers was made by dispersing GO in DMAc (dimethyl acetamide) and then adding SWCNT to the solution. The solution was mixed well using ultrasonication and high‐speed stirring. 1 wt% amount of nano‐filler solutions was added to PAN liquid to make PAN nanocomposite films. The films were tested for mechanical properties, electrical resistivity, thermoxidative stabilization, and thermal stability. The results showed that adding nano‐fillers to PAN significantly improved its tensile strength. GO increased the tensile strength by 42.9% (38.3 MPa), while SWCNT increased it by 57.3% (42.15 MPa). The combination of both (0.5 wt% SWCNT + 0.5 wt% GO) had a remarkable effect, increasing the tensile strength by 96% (52.53 MPa). This was because the combination of both prevented SWCNT from agglomerating together and made it interact better with the PAN, forming a complete network. The combination of both also made the PAN oxidize and stabilize early and efficiently during heating, which made its residual weight increase by ~5.5% more than pristine PAN in TGA. The electrical resistivity and SEM micrograph data correlate with the thermal analysis data, showing that PCG (1 wt% combination) reached the percolation threshold because of the benefits of both GO and SWCNT. The combination of both also showed 95.6% synergy in tensile strength compared to individual nano‐fillers, indicating its potential for efficient reinforcement. Highlights: Hybrid filler boosts PAN strength from 26.8 to 52.53 MPa, surpassing PC, PG.TGA: ~5.5 wt% increased residual weight in 1 wt% hybrid‐reinforced PCG composites.Hybrid undergoes GO decomposition, early oxidation and improved stabilization.PCG composite: Enhanced oxidation, improved stabilization via SWCNT network.PC & PCG composites show low volumetric resistivity due to SWCNT network. [ABSTRACT FROM AUTHOR]

Blending with ductile polycaprolactone (PCL) is one of the common toughening methods for polylactic acid (PLA). However, it seems inevitable to experience a trade‐off in mechanical strength and thermal stability of PLA. Therefore, this study aimed to improve the mechanical and thermal properties of PLA/PCL blends by adding different contents of talc (0–10 wt%) and conducting annealing treatments. Interestingly, the maximum tensile strength (52.04 MPa), elongation at break (83.51%), and impact strength (6.05 kJ/m2) were achieved by incorporating 2.5 wt% talc into the blends without annealing. Meanwhile, the addition of just 1 wt% talc shortened the semi‐crystallization time of PLA to one‐third of the neat PLA at 100°C. Particularly, after annealing treatment, the crystallinity of PLA increased to 32.1%, and the Vicat softening temperature reached as high as 133.3°C with 2.5 wt% talc. Importantly, the increase in crystallinity did not compromise the toughness of PLA composites but significantly enhanced the impact strength to 8.91 kJ/m2. This study provides an updated understanding of the relationship between toughness and crystallinity in PLA composites. Highlights: Thermo‐resistance of polylactic acid (PLA) composite increases to 133.3°C.Talc aids nucleation and promotes PLA crystallization.Increased crystallinity and high toughness are simultaneously realized.Adding 1 wt% talc reduced PLA semi‐crystallization time by one‐third.Crystal transformation and sea‐islands structure are vital for reinforcements. [ABSTRACT FROM AUTHOR]

Environment friendly polymer composites made of plant based natural fibers such as bamboo fiber, roselle fiber (RF), aloe vera fiber (AF) oil, or kenaf fiber are cardinal of the current world toward sustainability. They offer lower carbon footprint, higher biodegradability, higher specific strength, higher thermal, and acoustic characteristics. On the other hand, properties of synthetic glass fibers (GFs) such as high specific strength to weight ratio, great resistance during impact, and high durability extend their application perspective for various engineering materials. As such, in the present study, mechanical properties and thermal stability of hybrid laminate comprising of natural fiber (i.e., AF and RF) and synthetic fiber (i.e., GF) fabricated using hand layup process were investigated. Experimental findings reveal that sequencing of the fibers significantly affects properties of the composite. Introducing a layer of AF between RF increased the tensile strength by 30.2% respectively while hybrid laminates composed of three successive layers of RF exhibited 12.6% higher impact strength compared to hybrid laminate composed of AF. Besides, the thermal stability of hybrid laminates was higher (i.e., minimal weight loss of <6.1% when heated up to 800°) compared to neat polymer or laminates with single reinforcement. The enhanced thermal stability, mechanical properties, and tribological properties of the "greener" hybrid laminates can be employed in various structural or lightweight industrial applications. Highlights: Hybridization using natural fibers and synthetic fibers are attempted and investigated.Fiber sequencing significantly affects mechanical properties of the composite.Higher thermal stability of hybrid laminates, that is, minimal weight loss of <6.1% when heated up to 800°.Laminated composed of AF in between RF exhibited lowest frictional coefficient."Green" hybrid polymer laminate suitable for various structural and lightweight industrial applications is identified. [ABSTRACT FROM AUTHOR]

The study evaluated the effect of adding different proportions (3/7, 1/1, and 7/3) of pineapple leaf fiber to composites reinforced with olive trunk leaves powder by measuring tensile properties, moisture absorption, and thermal stability. The results showed that the proportion of pineapple leaf fiber in the hybrid composites strongly influenced tensile properties, moisture absorption, and thermal stability. Increasing pineapple leaf fiber loading from 12 wt% to 28 wt% resulted in an important increase in tensile strength, namely an average of 46%. However, the tensile strength and Young's modulus of the hybrid composites were inferior to those of the parent composites, which could be attributed to the relative inability of the hybrid composites to withstand tensile loads. Thermo‐gravimetric analysis results showed that the introduction of even the lowest amount of pineapple leaf fibers in the olive trunk leaves improved the thermal stability of the composites, bringing the degradation onset above 240°C, therefore suggesting the possibility of a future processing with most thermoplastic matrices. The differences in thermal stability between epoxy composites with 7/3 olive trunk leaves powder/pineapple leaf fiber, 1/1 olive trunk leaves powder/pineapple leaf fiber, and 3/7 olive trunk leaves powder/pineapple leaf fiber were very limited. Regarding moisture absorption, the presence of olive trunk leaves powder considerably reduced the weight gain, and also passing from 1/1 to 7/3 olive trunk leaves/pineapple leaf fibers offered a distinct advantage, measurable as more than 1% reduction in water saturation content. [ABSTRACT FROM AUTHOR]

The effect of three types of nanofillers on the physical, mechanical, and thermal properties of flexible polyurethane foams (FPUF) was studied. FPUF with nanofillers are of interest to the automotive industry due to their potential for enhancing compression properties and enabling sustainable foams. Holey and wrinkled flash graphene, and untreated and silane coated boron nitride were tested as fillers up to 0.1 wt% loading level. Flash graphene filled FPUF showed significant improvement in compressive properties, especially at the 0.025 wt% loading level, showing a 22% increase in compressive force deflection at 25% strain and a 17% increase at 50% strain compared to the unfilled control foam sample. Boron nitride nanoparticles, treated and untreated, were shown to be an effective means of reducing wet compression set properties, addressing a key area of concern for sustainable polyols. Wet compression set was reduced by 20%–30% for most boron nitride foams compared to their unfilled control samples. Boron nitride may enable implementation of more sustainable polyols in automotive FPUF. Nanofillers did not significantly improve thermal stability of FPUF. [ABSTRACT FROM AUTHOR]

Few‐layer molybdenum disulfide (MoS2) was prepared by liquid phase exfoliation with in‐situ modification as a nanofiller for polypropylene (PP). Scanning and transmission electron microscopies (SEM, TEM) showed uniform dispersion and excellent adhesion of MoS2 within the PP matrix. When MoS2 was centrifuged at 1000 rpm, the mechanical properties of the composite were greatly improved by adding only 0.5 wt.% of MoS2. The yield strength, bending modulus, and impact strength increased by 2.3%, 8.9%, and 44.03%, respectively. X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) showed that the enhanced mechanical properties of the composites were related to PP crystallographic transformation. Thermogravimetric analysis (TGA) showed that the incorporation of 2 wt.% MoS2 increased the maximum weight‐loss temperature of the composites by approximately 30°C. The mechanisms for increasing thermal stability have been thoroughly demonstrated by band energy analysis. MoS2 nanosheets have high aspect ratios and strong insulation with a change in band gap width compared to bulk MoS2, which is resulting in the stronger interactions at the MoS2/PP substrate interface. Furthermore, due to the outstanding carrier for rigid and thermally stable materials, MoS2 composites displayed excellent mechanical and thermal properties. In addition, unlike PP, the melt flow rate (MFR) of composite materials is more conducive to downstream product processing. This will further promote the application scope of MoS2/PP composites. [ABSTRACT FROM AUTHOR]

To attain interface‐engineered polypropylene/cellulose nanofibril (PP/CNF) composites with improved thermal and mechanical performance, PP was grafted with glycidyl methacrylate (GMA) and styrene via direct melt‐mixing and GMA/styrene‐grafted PP (PGMA) was reinforced with 1–10 wt% CNF content through a mass‐producible melt‐compounding process. The spectroscopic analyses confirmed the existence of specific hydrogen‐bonding interactions between CNF and PGMA in the composites. The melt‐rheological measurement revealed the occurrence of chemical reactions between the hydroxy group of CNF and the glycidyl group of PGMA of the composites. Accordingly, the dispersion and interfacial adhesion of CNF in the PGMA matrix was improved. β‐form PP crystals were also developed by accelerating the crystallization of PGMA and PGMA/CNF composites, unlike PP with only α‐form crystals. The storage modulus of PGMA/CNF composites was enhanced noticeably with increasing CNF content. Moreover, the impact strength of PGMA composite with 1 wt% CNF was found to be 29.2% higher than that of neat PP. [ABSTRACT FROM AUTHOR]

Cyanate ester (CE) resin is usually used as high‐temperature resistant or microwave absorbing material in aerospace field because of its high‐glass transition temperature, low‐curing shrinkage, and excellent dielectric properties. However, CE resin has the disadvantages of high‐curing temperature, high brittleness, and poor toughness, which limits its application in the field of aerospace. In this article, CE resin is modified by high‐performance thermoplastic engineering plastic polyether sulfone (PES) to obtain a modified resin with excellent toughness. The thermoplastic/thermosetting semi‐interpenetrating network system formed by PES and CE resin can greatly improve the mechanical and thermal properties of PES modified CE resin. The results show that the flexural strength and impact toughness of CE resin castings modified with 10 wt% PES are 56% and 63% higher than those of CE resin castings. At 800°C, the retention weight of CE resin castings with 12.5 wt% PES content increased from 19.0% to 28.1%, which shows that the heat resistance of CE resin is greatly improved by PES. Compared with carbon fiber reinforced CE resin (CF/CE) unidirectional composite, the flexural strength of CF/CE‐P‐10 composite is increased from 1649.6 to 1959.8 MPa; the interlaminar shear strength is increased from 61.3 to 84.2 MPa; the impact strength is increased from 225.9 to 346.4 kJ/m2; and the interlaminar fracture toughness is increased from 5.34 to 11.38 J/m2. [ABSTRACT FROM AUTHOR]

This research article has developed a novel composite material using natural fiber and PAN fiber. The study aims to remove harmful materials from the composites on the market these days. Asbestos and aramid fiber has good properties and is used in those composites where good mechanical properties are needed. However, using these materials causes many environmental issues and harms humans and other animals. There are very rare studies of PAN and natural fiber based hybrid composites. So Grewia optiva, which has good mechanical properties, and PAN fiber, which has good tribological properties, has been used to develop composites. The percentages of both materials were taken (4–16 wt%) with other ingredients such as phenolic resin, G. optiva fiber, PAN fiber/Kevlar, and lapinus ceramic, potassium barium, titan, mica, and ceramic. The developed composites have shown physical, mechanical, and tribological properties. [ABSTRACT FROM AUTHOR]

In this study, we report an efficient and rapid technique to achieve the covalent functionalization of multiwalled carbon nanotubes (MWCNTs) by hyperbranched poly(thiol ether‐ester) (HPTEE) via thiol‐yne click chemistry method. The structures of the MWCNTs grafted with HPTEE (MWCNTs‐HPTEE) were characterized and their effects on the epoxy‐based composites were investigated. It was found that the hyperbranched polymers have been successfully grafted onto the MWCNTs surface thorough covalent bonds, which can greatly improve the dispersion of MWCNTs in epoxy matrix and the interfacial interaction between them, contributing to the largely enhanced mechanical and thermal properties. When 0.6 wt% MWCNTs‐HPTEE was added, the composites exhibited the best mechanical properties. An impressive 180% increase in the impact strength and 72.3% increase in flexural strength were observed with respect to the neat epoxy resin. Moreover, at the same filler content, the thermal stability and thermal conductivity of MWCNTs‐HPTEE/epoxy composites outperformed the composites containing the raw MWCNTs. Experimental results demonstrated that the resulted MWCNTs‐HPTEE are more effective on the improvement of properties of epoxy‐based composites as compared with raw MWCNTs. [ABSTRACT FROM AUTHOR]

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

Glass fiber reinforced epoxy matrix is modified with a hybrid combination of fillers, and composites were fabricated using the advanced pultrusion technique. The focus of the investigation was to comprehensively understand the synergy between the carbon nanofillers and the role of aluminum trihydride on the thermal characteristics. A ratio of 2 wt% of multiwalled carbon nanotubes and 3 wt% of graphene is established by prior optimization technique for improved thermal properties. Using X‐ray diffraction analysis, the presence of the two carbon fillers was confirmed. Aluminum trihydrate was incorporated in the epoxy matrix with the objective of improving the thermal properties. By thermogravimetric analysis and differential scanning calorimetry, assessment of the thermal properties of the composites has been undertaken. The use of the two carbon fillers leads to enhancement of the thermal properties and contrary to expectations, the composites with hybrid fillers undergo minimal degradation due to pyrolysis. Uniform dispersion of the nanoparticles and good interfacial bonding of fillers with the epoxy are observed to be critical for the enhancement of thermal properties. The ratio of the two carbon fillers used helps in their preferential alignment and hence significant improvements in thermal properties are observed. Glass transition temperature reveals a 13°C increase increases due to the inclusion of carbon nanofillers and aluminum trihydride. [ABSTRACT FROM AUTHOR]

Despite the growing interest in utilizing starch‐based biodegradable films, their low mechanical properties generally limit them from being widely used. On the other hand, brewer's spent grain (BSG) is an abundant by‐product that does not yet have high added‐value industrial use. This study proposes the development of starch‐based composites filled with BSG for applications in biodegradable films. Different contents (1–5 wt%) of BSG fibers of different sizes (35, 60, and 100 mesh) were used aiming to identify the film compositions with better mechanical and thermal properties. The composites were produced by casting and had their mechanical, morphological, and thermal properties evaluated. The composites with the most promising mechanical properties contained 2.5 wt% BSG with 35 mesh and 1 wt% BSG with 100 mesh. Lower amounts of smaller BSG fibers resulted in balanced mechanical properties because of their higher surface area‐to‐volume ratio and higher aspect ratio. Results revealed that incorporating BSG may slightly improve the tensile strength and thermal stability of pure TPS, thus acting as a promising active filler due to the compatibility with the polymer matrix and increased polymer crystallinity. The developed films contribute to the circular economy and might be a promising low‐cost option for application in conventional packages or mulch films. [ABSTRACT FROM AUTHOR]

In this study, a kind of novel curing agent composed of acrylic acid and 4,4′‐(hexafluoroisopropylidene)bis(p‐phenyleneoxy)dianiline was mixed, with different contents of diatomite (CP) particles, into the epoxy resin (E51) to obtain bio‐composites that can be rapidly molded and cured at room temperature. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry were used to study the curing behavior of epoxy resin and bio‐composites. The influence of CP particle dosages on the mechanical, including tensile, flexural and impact properties, and thermal properties of the prepared composites were discussed. Thermogravimetric analysis result showed that the thermal stability increased with increasing of CP fillers content. Dielectric property tests confirmed that the dielectric constant of composites decreased attributed to the incorporating of novel curing agent and CP fillers with porous structure into epoxy resin. Finally, Scanning Electron Microscope revealed the excellent adhesion between the cured resin and the fillers. [ABSTRACT FROM AUTHOR]

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

In this paper, oil palm fiber (OPF) and pineapple fiber (PALF) reinforced biophenolic resin (BPHR) composites and hybrid composites were fabricated by hand lay‐up technique. Structural, thermal and mechanical properties of pure and hybrid composites analyzed by Fourier transform infrared (FTIR), thermal gravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), and universal testing machine. Achieved results indicated that OPF/PALF hybrid composites show better properties as compared with pure composites. It was observed that the tensile and flexural characterizations improved with incorporating OPF and PALF fibers into BPHR composites in comparison to the neat BPHR matrix. The results of the thermal stability obtained from TGA tests showed that the reinforcement of pure fiber composites (OPF and PALF) and hybrid composites (OPF/PALF) in BPHR matrix were improved in comparison to that of neat BPHR matrix. The final decomposition temperature of 50% OPF and 3OPF/7PALF was the highest among all other composites (415.80 and 415.42°C). On the other hand, the residual amount of hybrid composite (1OPF/1PALF) was (24.43%), while the lowest residual amount exhibited in pure composite (50% PALF), which was 20.08%. The reinforcement of pure composite and hybrid composites into BPHR also improved the storage and loss moduli; however, the pure composite sample (50% OPF) exhibited a more significant increase than other composites loadings. Furthermore, the damping factor was reduced significantly by the reinforcement of hybrid composites over pure composites. This study showed that obtained hybrid composites are suitable to apply in various structural and nonstructural applications. [ABSTRACT FROM AUTHOR]

Polyamide nanocomposites (PANC) were prepared from an aliphatic–aromatic polyamide (PA) containing hydrazide–hydrazone groups in the side chain, reinforced with functionalized polyethyleneimine (FPEI)/modified Mg(OH)2 nanoparticles (FPMN). For this purpose, a new structure, aromatic diamine (DAHH), containing the hydrazide–hydrazone group, was synthesized, and used to synthesize PA by direct polycondensation. Also, polyethyleneimine (PEI) was structurally modified with salicylaldehyde for the modification of the surface of Mg(OH)2 nanoparticles (MDH). The Field‐Emission Scanning Electron Microscopy and X‐ray diffraction results revealed that MDH were uniformly dispersed in nano‐size in the PA matrix. The thermogravimetric analysis results in both N2 and air environments showed that PANC possesses higher thermal resistance than that of the neat PA. The 5% degradation temperature (T5) of PANC containing 8 wt% of FPMN was obtained 40°C more than that of the pure PA in the N2 environment. The microscale combustion calorimetry (MCC) results exhibited that the loading of FPMN into the PA matrix can efficiently increase the combustion resistance by decreasing the MCC parameters such as the heat release rate values. In addition, the lead ions adsorption efficiency of the prepared nanostructure materials was investigated, and the results exhibited that the adsorption data were obtained following the Langmuir isotherm model. The maximum adsorption efficiency was calculated to be 99.96% for PANC 8. [ABSTRACT FROM AUTHOR]

The article discusses the fabrication, mechanical characterization, and heat resistance of nano ZnO‐TiO2‐filled glass fiber‐reinforced LY556 epoxy composites, with focus on the synergistic effect of ZnO and TiO2 nanofillers. The fabrication of the composite laminates is achieved by the addition of the nanofillers in different wt% ranging from 1 to 5 wt%. The composites are prepared using simple hand layup technique followed by curing under vacuum. The 3D atomic force microscopy scans indicated even distribution of the nanofillers up to 2 wt% loading. Severe agglomeration of the nanofillers is evident for 3 to 5 wt% loading. The surface roughness, microhardness, flexural strength, tensile strength, and impact strength of the composites indicate a relationship with dispersion, wt% loading, and the wettability of the nanofiller with the LY556. In general, it is found that the incorporation of hard nanofillers favored the improvement of impact strength to a greater extent compared to tensile and flexural strengths. Detailed analysis of the obtained mechanical property values favors an optimum 2 wt% incorporation of the selected nanofillers to obtain improvement in various strength values of the fabricated composites. The thermal stability of the fabricated composites improved through the incorporation of ceramic nanofillers. [ABSTRACT FROM AUTHOR]

The carbon fiber‐ZrO2(CF‐ZrO2) hybrid was prepared through one‐step hydrothermal method, which well realized the synergistic enhancement of CF and ZrO2 nanoparticles on the wear‐resistant performance of polyimide (PI) composites. Results showed that the ZrO2 nanoparticles were tetragonal and monoclinic mixed phase. The average particle size was about 10 nm. And they were in‐situ synthesized on the surface of CF, which endowed CF with much rougher surface and further improved the interfacial adhesion of PI composite. Moreover, the CF‐ZrO2 hybrid reinforced PI composite possessed higher shore hardness and thermal stability than those of PI or its composite reinforce with single CF because of CF with good compressive strength and ZrO2 with outstanding thermal property. In addition, the anti‐wear properties of the PI were greatly improved by filling CF‐ZrO2 hybrid, which was mainly because CF as the main bearing phase of the friction surface of the composites could bear most of the stresses onto the worn surface and protect the polymer matrix from severe wear in the sliding process. Meanwhile, the ZrO2 nanoparticles presented at the interface of CF and PI could not only carry the applied load, but also enhance the interfacial combination of CF with PI to form a good stress transfer and prevent the failure of CF, finally improving tribological properties of composites. Besides, the PI/CF‐ZrO2 kept reasonable friction and wear performance under high loads and rotating speeds. [ABSTRACT FROM AUTHOR]

Epoxy resin (EP) has received extensive attention in the field of mechanical engineering due to its outstanding physical mechanical performance and chemical stability. However, relatively weak thermal and abrasion properties seriously limit its application in motion conditions. Here, we report copper‐graphene nanohybrids (Cu‐G) prepared by a space‐confined thermal disintegration method as promising materials for improving the thermal and tribological properties of epoxy composites. Impressively, the thermal conductivity and stability properties of EP/Cu‐G composites present obvious enhancements compared to pure EP. Meanwhile, the tensile strength and elongation at break of EP/Cu‐G are increased by 8.0% and 7.5% compared to those of pure EP. In addition, sliding test results reveal that the wear rate of EP/Cu‐G composites show a 66.7% decline, which can be ascribed to the synergistic enhancement effects between graphene and Cu. [ABSTRACT FROM AUTHOR]

A series of PVC films stabilized with novel antimicrobial itaconimido aryl 1,3,4‐oxadiazoles (D1'‐D4'), at absence or presence of various concentrations of multiwalled carbon nanotubes (MWCNTs), was prepared by a conventional solution casting method. D1'‐D4' was prepared via thermal cyclization processes by loss of water for their congruous predecessors itaconimido aryl hydrazides. Elemental analysis and various spectroscopy measurements were used to prove their structures. D1'‐D4' have great antimicrobial activities and some of them showed similar or sometimes higher impact than the reference antibiotic. From TG measurements in nitrogen, they have high thermal stabilities and their decomposition temperatures were above 275–310°C in accordance with substituent groups NH2 and/or OH incorporated into their structures. They have higher thermal stabilizing efficiencies for PVC in comparison with some industrial thermal stabilizers. Inclusion of 0.1–0.5 wt% MWCNTs into PVC films, that were stabilized with D4', enhanced the composites thermal stability. XRD, SEM as well as TEM were used for ascertaining of incorporation and well dispersion of MWCNTs into PVC matrices. Additionally, the efficacy of stabilization has been proven via a decreased rate of color alteration, mechanical properties change and chains cleavage for PVC. The high antimicrobial and thermal characteristics of these stabilizers afford them a great possibility to secure antimicrobial thermally stable PVC composites. Also, improvement of thermal and mechanical properties of PVC stabilized by D4' after its incorporation with MWCNTs afford a great possibility to its application in different fields where their thermal resistance and high tensile strength resistance play a very important role. [ABSTRACT FROM AUTHOR]

Biocomposites containing natural fibers and biopolymers are an ideal choice for developing substantially biodegradable materials for different applications. Polylactic acid is a biopolymer produced from renewable resources and has drawn numerous interest in packaging, electrical, and automotive application in recent years. However, its potential application in both electrical and automotive industries is limited by its flame retardancy and thermal properties. One way to offset this challenge has been to incorporate natural or synthetic flame retardants in polylactic acid (PLA). The aim of this article is to review the trends in research and development of composites based on agricultural fibers and PLA biopolymers over the past decade. This article highlights recent advances in the fields of flame retardancy and thermal stability of agricultural fiber‐reinforced PLA. Typical fiber‐reinforced PLA processing techniques are mentioned. Over 75% of the studies reported that incorporation of agricultural fibers resulted in enhanced flame retardancy and thermal stability of fiber‐reinforced PLA. These properties are further enhanced with surface modifications on the agricultural fibers prior to use as reinforcement in fiber‐reinforced PLA. From this review it is clear that flame retardancy and thermal stability depends on the type and pretreatment method of the agricultural fibers used in developing fiber‐reinforced PLA. Further research and development is encouraged on the enhancement of the flame retardancy properties of agricultural fiber‐reinforced PLA, especially using agricultural fibers themselves as flame retardants as opposed to synthetic flame retardants that are typically used. [ABSTRACT FROM AUTHOR]

Industrial waste red mud (RM) was filled in the chlorinated polyethylene rubber (CPE) to replace carbon black (CB) at various ratios, that is, RM/CB (40/20, 20/40, 10/50, 5/55, 0/60) in the production of CPE/RM composite materials. The mechanical and thermal properties of CPE/RM with varied proportion of RM and CB were studied. The tensile strength of the CPE/RM/CB composite were improved compare to without RM (ie, improved from 10 to 14 MPa) and thermal degradation temperature (Td2) has improved from 435°C to 445°C, when the content of red mud was 20 phr. After aging for 3 days, the hardness and tensile strength of CPE/RM/CB composites were improved, that is, increment in hardness by 10 shore A and tensile strength by 2 MPa. CPE shows good thermal stability (with Td2 = 445°C) with the increment of RM and CB proportion, noticeably, when the ratio of red mud/carbon black is 20/40. The analysis by RPA (Rubber Process Analyzer) showed Payne effect became apparent when the amount of red mud was more than 20 phr. The compound with 60 phr CB load showed the largest elastic modulus G′ which decreased fastest at strain 0.28%, almost as the same as 40/20 CB/RM, but the elastic modulus G′ of 40/20 CB/RM showed a slight decrease when the strain exceeded 65%. The overall properties of the composite filled with 20 phr red mud were better in comparison with other varied ratios. The developed composite can be used to manufacture plastic runway or rubber hose. [ABSTRACT FROM AUTHOR]

The high thermal conductivity epoxy resin composites filled with inorganic filler can improve the low thermal conductivity of epoxy resin. However, a large number of fillers with high thermal conductivity will reduce other properties of the composites, which limits their use under high voltage, high temperature and strong mechanical force during operation. In this study, the dopamine‐modified BN (DBN) and k‐DBN (DBN modified by coupling agent KH‐560) were prepared by employed the dopamine with catechol groups and coupling agent to modify boron nitride. The thermal conductivity, thermal stability, and dielectric properties of composites with different contents of modified fillers were studied. The results showed that surface modification improved the dispersibility of BN in the resin matrix and compatibility with the resin. Among BN/EP, DBN/EP, k‐DBN/EP composites, k‐DBN/EP composites had the highest thermal conductivity at the same number of additions. When the k‐DBN/EP content was 30 wt%, the thermal conductivity of the composite was 0.892 W/(m·K), which was an increase of 25.5% compared with the BN/EP composite. The appropriate amount of BN filling (20 wt%) can improve the breakdown strength of the composite material. [ABSTRACT FROM AUTHOR]

The effect of the ultrasonic/mechanical stirring method (physical treatment) and 3‐glycidoxypropyltrimethoxy silane (GPS, chemical treatment) modifications on the sugarcane fiber (SGF)/epoxy composites was investigated to improve the interfacial interaction between fiber and epoxy resin. An optimum concentration GPS at 2 wt% was found for the best improvement in tensile strength at 40 wt% SGF content based on the evaluation of GPS content, indicating the role of GPS as an effective coupling agent. Overall, the best improvement in tensile strength was observed for GPS‐modified cases, and particularly tensile strength reached up to 32.9 MPa at 50 wt% of fiber content. In addition, three types of Polyurethane (PU)‐modified epoxy with different polyols at various SGFs contents were investigated. In all cases, the tensile strength of SGF/PU‐epoxy cases was higher than that of SGF/epoxy cases due to the relatively lower viscosity of PU‐epoxy to easily wet the SGF surface. In general, impact strength for samples without physical or chemical treatment also ranked the lowest value in most cases. The enhanced interfacial interaction between SGF and epoxy for surface‐modified cases was suggested through the morphology observation, dynamical mechanical analysis, and the onset degradation improvement in thermal stability. [ABSTRACT FROM AUTHOR]

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

The present work is a comparative study of the impact of different Alfa fiber modifications on fiber properties, as well as on polylactic acid (PLA) composites behaviors. A specific process that combines successively mechanical, chemical, and enzymatic treatments (xylanase and pectinase) was employed to optimize the performances of Alfa fibers. The treatments reduced the levels of lignin, hemicellulose, and pectin in the fibers. This reduction was associated with a rise of defibrillation degree, an increase of cellulose content and an enhancement of thermal stability, as shown with SEM observations, biochemical composition determination, FTIR measurements and thermo‐gravimetric analyzer results. Bio‐composites were fabricated using a twin‐screw extruder and an injection‐molding machine with a fiber load of 20%. Tensile, flexural and water absorption tests revealed an improvement of mechanical strengths and water resistance for the treated fibers composites, with the enzyme treatment being the most efficient. SEM analysis showed a better impregnation and distribution of enzyme treated fibers within the matrix. An improvement of the thermal properties of composites filled with Alfa treated fibers was noticed when compared with untreated fibers composites. The data indicated that the technology of enzymes can be used as a powerful and eco‐friendly approach to treat natural fibers and to increase their potential of reinforcement. [ABSTRACT FROM AUTHOR]

Functionalized graphene has a promising prospect in improving the thermal, mechanical, and flame‐retardant properties of polymer composites, which was unfortunately limited by the low yield and high pollution during graphene production. In this study, we reported a facile and eco‐friendly electrochemical approach to prepare ferric diethylenetriaminepentakis (methylphosphonic acid) functionalized graphene nanosheets (FGNS), which were subsequently used to fabricate polyacrylonitrile (PAN) composite fibers by a wet spinning strategy. Composite fibers showed better thermal stability above 350°C in contrast to pure PAN. Furthermore, a significant improvement on flame‐retardant properties of PAN fibers in the case of peak heat release rate (decreased by 36.7%) was caused by the inclusion of FGNS. The analysis results of condensed phase revealed that FGNS facilitated the formation of the compact and graphitic char residues, protecting underlying composite fibers during combustion. With adding 3.0 wt% FGNS, the tensile strength and breaking elongation of PAN composite fibers achieved 67.6% and 126.5% increment, respectively. This electrochemical method provides an eco‐friendly approach for scale production of functional graphene. [ABSTRACT FROM AUTHOR]

Polyurethane‐imide (PUI) foams, in combination with the mechanical performance of polyurethane and flame retardancy of polyimide, were prepared by polyimide prepolymer method. Expended vermiculite (EV), with a wider layer spacing than vermiculite, was used as the filler to further enhance the mechanical and thermal properties of the PUI foams. The effect of filler content on the morphology of foams was also investigated. The results showed that the mean cell diameter of foams became smaller and the cell size distribution was more uniform at low filler content. The addition of EV resulted in a substantial increase in thermal stability. The compression strength increased from 0.024 to 0.065 MPa with an increase in EV content from 0% to 9.6%. The limited oxygen index values increased from 24% to 30.8% with an increase in filler content from 0% to 9.6%. Hence, PUI foams could significantly enlarge its application range with the addition of EV. [ABSTRACT FROM AUTHOR]

Herein, Ti3C2Tx (MXene) was synthesized and mixed with polyvinyl alcohol (PVA) to fabricate PVA/MXene nanocomposites. The results confirmed that delaminated MXene was successfully synthesized. The nanocomposites were obtained via casting/evaporation method. The thermal stability was evaluated by thermogravimetric analysis (TGA). For the PVA composites with content of 2 wt% MXene (PVA‐MXene2), the thermal decomposition was retarded by approximately 20°C when the temperature was lower than 350°C compared with that of pure PVA. Moreover, the evolved gas products of the PVA/MXene composite were lower than those of pure PVA. For the first time, the flame retardancy of PVA/MXene nanocomposite was investigated using a microscale combustion calorimeter. The peak heat release rate (PHRR) and total heat release of the PVA composite were reduced by 25.7% and 25.5%, respectively, with 1 wt% of MXene. The temperatures at PHRR of PVA/MXene composites were improved with the addition of MXene. Moreover, the addition of MXene resulted in PVA composites with a higher tensile strength and elongation at break than those of a pure PVA film. The improvements in the flame retardancy, thermal and mechanical properties of PVA/MXene composites should enable a wide range of potential applications of MXenes in polymer matrices. [ABSTRACT FROM AUTHOR]

We describe ethylenediamine‐modified graphene oxide (GO)/co‐polyamide (GO‐EDA/CO‐PA) nanocomposites prepared via solution blending with EDA‐modified GO (GO‐NH2/EDA). GO was prepared via the improved Hummers method, and EDA was used to modify the GO to add amine groups to graphene. X‐ray diffraction, Fourier‐transform infrared spectroscopy and atomic force microscope analysis showed that the thickness of GO‐NH2/EDA was 1.2 nm. Amino functional groups were introduced onto the GO sheets. Due to the steric hindrance effect of the amino on modified graphene as well as the strong, specific interactions between aminos and carboxyls on CO‐PA, the GO‐NH2/EDA filler was homogeneously dispersed in the matrix, and the interface reaction was effectively improved. The GO‐NH2/EDA could change the crystal structure of pure nylon and the glass transition temperature (Tg). The mechanical properties of the nanocomposites increased dramatically when the GO‐NH2/EDA content is 0.6 wt%. The tensile strength and yield strength of the nanocomposites increased by 50.3 and 134.8%, respectively. The effects of interfacial interaction, increased crystallization, and prevention of agglomeration of GO‐NH2/EDA improved the thermal properties of the GO‐EDA/CO‐PA nanocomposites. This is because the 50% thermal degradation temperature (T‐50%) and the thermal degradation temperature (Td,max) of the nanocomposites increased by 16 and 15°C when the GO‐NH2/EDA content is 0.8 wt%. The nano‐filler improves the thermal diffusivity of the nylon matrix at low temperature. POLYM. COMPOS., 40:3315–3324, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Nanocomposites films based on low‐density polyethylene (LDPE) and different compositions of treated and untreated nanoperlite were prepared via melt mixing of the ingredients on a corotating twin‐screw extruder and then film blowing the nanocomposites. The physical dispersion of the nanocomposites is confirmed using Fourier transform infrared‐attenuated total reflectance (FTIR‐ATR) method. According to the thermal studies, the nanocomposites with untreated nanoperlite showing higher melting temperature and crystallinity, while their thermal stability is lower than nanocomposites with treated nanoperlite. The thermal and FTIR‐ATR studies also revealed the ethylene absorption of the nanocomposites. According to the surface energy results, the treatment of the nanoparticles completely changes the surface behavior and hydrophobicity of the films. Finally, peel color index and field study observations showed that increase in nanoperlite will increase the shelf life of the fruits; however, the nanocomposite with 6% untreated nanoperlite is the best choice for the packaging applications. POLYM. COMPOS., 40:2929–2937, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Two biocomposites based on cellulose (UFC) and starch modified urea formaldehyde (UFS) resin (F/U ratio of 0.8) were synthesized using the same procedure. The hydrolitical, thermal, and radiation stability of biocomposites are determined. Also, released formaldehyde during the acid hydrolysis is determined. Biocomposites based on modified UF resin have been irradiated with (50 kGy). Cellulose modified UF resin after γ‐radiation has 1.38% released formaldehyde; unmodified UF resin has 2.21% released formaldehyde. Thermal stability of biocomposites is determined using nonisothermal thermogravimetric analysis, differential thermal gravimetry (DTG), and differential thermal analysis with IR spectroscopy. Moving the DTG peak to higher temperatures indicates an increased thermal stability of cellulose modified UF resin, which is confirmed by the FTIR analysis. Gamma radiation most often causes a decrease in the intensity of the peaks in the FTIR spectrum. POLYM. COMPOS., 40:1287–1294, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Phenolic hydrogel plates were successfully fabricated by a microemulsion-templated sol gel polymerization method. Then, the phenolic cryogel plates were obtained from the hydrogel plates freeze-dried by the lyophilizer. Ultimately, the phenolic cryogel plates (PCPs) and fiber glass cloth layers were compounded to be the phenolic cryogel composite plates (PCCPs). The pore morphology, mechanical, and thermal properties of the composites were investigated. The experimental results showed that the aerogels made by freeze-drying method and disposed by acetic acid and tert butyl alcohol had the best microstructure. In addition, it was discovered that the tensile strength of the plates had equally increased for approximately eight times after compounding with the glass fiber cloth layers and the mechanical properties of the 20 wt% and 25% solid content PCPs achieved the optimal value compared with PCPs of other contents. Moreover, it was found that the cryogels had excellent thermostability, and their thermal conductivity decreased with the reducing of the solid contents, what’s more, the joining of cloth layers had the increased the composites’ thermal conductivity to some degree. Finally, considering the requirement of low density, good mechanical, and thermal performance, the 20 wt% solid content PCCP had the best comprehensive performance compared with others. [ABSTRACT FROM AUTHOR]

In this article, a series of new silica/polyimide (SiO2/PI) nanocomposite films with high dielectric constant (>4.0), low dielectric loss (<0.0325), high breakdown strength (288.8 kV mm−1), and high volume resistivity (2.498 × 1014 Ω m) were prepared by the hydrolysis of tetraethyl orthosilicate in water-soluble poly(amic acid) ammonium salt (PAAS). The chemical structure of nanocomposite films compared with the traditional pure PI was confirmed by Fourier transform infrared spectroscopy and X-ray diffraction patterns. The results indicated that both the PAAS and the polyamide acid (PAA) material were effectively converted into the corresponding PI material through the thermal imidization and the amorphous SiO2 was embedded in the nanocomposite films without structural changes. Thermal stability of the nanocomposite films was increased though mechanical property was generally decreased with increasing the mass fraction of SiO2. All the nanocomposite films exhibited an almost single-step thermal decomposition behavior and the average decomposition temperature was about 615°C. It was concluded that the effective dispersion of SiO2 particles in PI matrix vigorously improved the comprehensive performance of the SiO2/PI nanocomposite films and expanded their applications in the electronic and environment-friendly industries. POLYM. COMPOS., 38:774-781, 2017. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

We reported a facile approach to fabricate graphene nanoplatelets (GNPs)/epoxy composites with a novel blend method. The influence of GNPs on the thermal and electrical properties was investigated. Compounds with different GNPs content (0-8 wt%) were mixed with a Flacktek speedmixer at a speed of 3000 rpm for 5 min. The thermal conductivity of the epoxy composites with 8 wt% GNPs was 1.181 W/m K, which is increased by 627% compared with those of the neat epoxy. It is found that the thermal stability and electrical property also have a certain degree of improvement. Scanning electron microscopy images demonstrate that the structures of the composites have a closed relationship with their properties. In addition, the incorporation of GNPs in epoxy matrix indicated excellent Vickers hardness at the low weight fractions of GNPs. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) and NPK fertilizer with empty fruit bunch (EFB) fibers were blends to produced bioplastic fertlizer (BpF) composites for slow release fertilizer. Thermal properties of BpF composites were investigated by thermogavimteric analysis (TGA), differential scanning calorimetry (DSC), and morphological and degradation properties were anlayzed by scanning electron microscopy (SEM), soil burial test, respectively. TGA themogram display that neat PLA, PLA/NPK, and BpF composites degradate at different temperatures. DSC curves of PLA and other composites exhibited same glass transition temperature (Tg) value indicating that both major blend components are miscible. The Tg, crystallization temperature (Tc), melting temperature (Tm) values also decreased with increased amount of fertilizer and fibers. The Tm of BpF composites did not change with an increase in fertilizer content because thermal stability of PLA and PLA/NPK composites was not affected. Soil burial and fungal degradation test of PLA, PLA/NPK, and BpF composites were also carried out. Soil burial studies indicated that BpF composites display better biodegradation as compared with neat NPK. Fungal degradation study indicated that fungi exposure times of BpF composites show higher value of degradation as compared with PLA/NPK. We attribute that developed BpF composites will help oil palm plantation industry to use it as slow release fertilizer. [ABSTRACT FROM AUTHOR]