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Novel Ti/Al laminated composite embedded with particles of the high entropy alloy Al0.5CoCrFeNi were produced by vacuum hot press sintering at 650°C. The microstructure of the laminated composite was investigated using XRD, SEM, EDS, TEM and EBSD techniques. It was found that a thin layer of Al3Ti was formed at the Ti/Al interface. There were no obvious defects between the Al0.5CoCrFeNi particles and Al matrix, achieving a good interfacial bond. The tensile properties of the material were tested at room temperature. The results of the tensile test indicated that the material exhibited an elongation to failure of 59% and an average tensile strength of 240 MPa, demonstrating excellent plastic deformation capability. During the tensile process, the expansion of fractures and cracks in Al0.5CoCrFeNi particles can consume energy, which helps to improve the material's ability to undergo plastic deformation. Based on the morphologies of tensile fracture, it has been observed that the fracture surface of high entropy alloys exhibits a mixed fracture mode consisting of both brittle and plastic fracture. The brittle BCC phase has been identified as the main cause of cracking in HEA. Ultimately, the material fractures due to necking. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HA) being the main mineral constituent of human hard tissues is highly bioactive. Good chemical bonds can be generated between HA and natural bone. However, the low strength and inherent brittleness of HA restrict its application usually to non-load-bearing conditions. In this work, production of a new kind of HA–ZrO2 composite by hot-press sintering method is described. Bioglass which has been widely used in reconstruction of damaged or diseased tissues was added into HA–ZrO2 composites. Comparing with pure HA ceramic, this type of composite possesses better mechanical strength and retains the bioactivity of HA as well. The liquid phase generated by bioglass has been effective in improving the sintering process of HA–ZrO2 composites. The phase composition of HA composite was characterized by XRD and their fracture surfaces were observed by SEM. The XRD results show that introducing a small amount of bioglass into HA–ZrO2 composite cannot enhance decomposition of HA. The SEM images show that there were fewer pores on the fracture surfaces of HA–ZrO2–bioglass composite than in the HA–ZrO2 composite. The flexural strength and toughness of HA–ZrO2 composite containing 2 wt% bioglass were 157 MPa and 1.63 MPa·m1/2, respectively. [ABSTRACT FROM AUTHOR]

Lightweight, electrically insulating and high thermally conductive materials are highly desirable in electronic and power systems because they can effectively transfer heat and avoid temperature rise of the equipment and devices, thus guaranteeing normal operation. In this work, silica-coated spherical boron nitride (SiO2@s-BN) was successfully fabricated and prepared as a thermally conductive composite by blending with silicone rubber (SR). Due to the modulus matching, SiO2@BN could decrease the thermal resistance between the SR matrices and the thermally conductive fillers, thus achieving higher thermal conductivity compared with the original BN at the same filler loading. When the SR composite is filled with 40 wt% SiO2@BN, the thermal conductivity can reach 1.2 W m−1 K−1, which is 16.5% higher than that of the 40 wt% s-BN/SR composite. Simultaneously, the 40 wt% SiO2@BN/SR composite material not only exhibits excellent dielectric, thermal, and mechanical properties but also demonstrates outstanding processability, maintaining a low precursor viscosity of only 14.5 Pa·s. Overall, this work provides a novel strategy for developing high thermally conductive SR composites with good processability. [ABSTRACT FROM AUTHOR]

This article extensively explores moisture resistance treatments for natural fiber-reinforced composites (NFRCs), aiming to mitigate the hindrance posed by their high moisture absorption and limited applications. The study delves into five distinct fiber treatments, emphasizing their roles in improving fiber separation, wettability, homogeneity, and crucial fiber/matrix adhesion by removing surface impurities. Chemical treatments applied are instrumental in inducing hydrophobic behavior in treated fibers, validated by Fourier-transform infrared spectroscopy (FTIR) analysis and an observed increase in water contact angle. Scanning electron microscopy (SEM) analysis underscores the treated NFRCs' superior mechanical properties, showcasing extensive fiber breakage and enhanced energy-dissipating mechanisms. The article employs a 2D finite element (FE) model to visually represent the impact of moisture resistance treatments on NFRCs using the thermal-moisture analogy. Treated samples initially exhibit faster moisture absorption than untreated epoxy, creating a moisture gradient. However, over time, treated NFRCs demonstrate reduced moisture absorption compared to neat epoxy, with the hydrophobic interphase actively attracting and subsequently retarding moisture progression. This comprehensive study identifies effective moisture resistance treatments for NFRCs. It explains their mechanisms, helping to understand how these treatments improve the performance of natural fiber-reinforced composites in practical applications. [ABSTRACT FROM AUTHOR]

The hierarchical carbonaceous nanofillers viz. carboxylated multiwalled carbon nanotube (MWCNT-COOH as 1D), hydroxylated few-layer graphene (FLG-OH as 2D), and hybrid 3D i.e., MWCNT-COOH immobilized into FLG-OH were dispersed into segmented thermoplastic polyurethane (TPU) by twin-screw extrusion (TSE). The concentration of nanofillers was varied as 0.25, 0.5, 1.0, 2.0 and 5 wt%. To increase the level of dispersion, hybrid 3D nanofillers were also incorporated into TPU by producing cellular structures through supramolecular self-assembly route (SSAR). The cellular structure in which the nanofillers were found to be uniformly dispersed was then compounded by TSE technique. The large-scale uniform dispersion was observed at higher loading (2 wt%) by SSAR followed by TSE when compared with direct TSE. Uniform dispersion was found at 1 wt% loading by direct TSE. PU nanocomposite film reinforced with 2 wt% hybrid 3D nanofillers showed good gas barrier property with ~63% reduction of helium gas permeability to 472 cm3/m2/day from 1287 cm3/m2/day of neat PU film. [ABSTRACT FROM AUTHOR]

Hemp woody core (HWC) that is a by-product of hemp industry was subjected to pre-treatment with alkali (mercerisation) and further functionalisation with epoxidised soybean oil (ESO) or (3-aminopropyl)triethoxysilane (APS). Mercerisation resulted in more developed surface area and rearrangement of fibrils into denser packing. FTIR spectroscopy analysis revealed the presence of hydrogen bonds of HWC with modifier in case of ESO application as well as hydrogen and Si-O-C covalent bonds in case of APS application. Two types of Si-containing epoxyurethanes were filled with 60% of HWC with different surface modification: the first polymer contained diglycidyl ether of bisphenol-A (DGEBA), while the second one contained ESO as an epoxy component. The investigation of the surface properties of composites found that the ones based on ESO epoxyurethane were more hydrophobic than their respective counterparts. Hydrophilicity was reduced by functionalisation of HWC providing a contact angle augment from 54°for DGEBA-containing sample with raw HWC to 86° for the one with oil modified HWC. The results of water uptake test showed that regardless of the matrix the composites reinforced with functionalised HWC exhibited about 40% less gain in weight at the saturation level than their analogues reinforced with untreated or alkali treated HWC. [ABSTRACT FROM AUTHOR]

In order to enhance the interfacial bonding between aluminum and β-Si3N4 whiskers in Al matrix composites (AMCs), Ni coating was deposited on the surface of β-Si3N4 whiskers using an electroless plating method. The interfacial test results showed that Ni coating was successfully deposited on the surface of β-Si3N4 whiskers and the whiskers were well bonded with Al matrix without pores. In addition, the whiskers were homogeneously dispersed in the Al matrix. The effect of Ni-coated β-Si3N4 whiskers on the mechanical properties of composites was investigated in detail. Densification and the mechanical performance of AMCs reinforced by Ni coated β-Si3N4 whiskers (NSAMCs) were improved comparing to that of AMCs reinforced by uncoated β-Si3N4 whiskers (USAMCs). The maximum value of tensile strength and bending strength reached up to 290 MPa and 487 MPa, when the Ni content was 0.9 vol.% and the β-Si3N4 whiskers content was 20 wt.%, respectively. However, excessive Ni content weakened the strengthening effect. Medium Ni coating on β-Si3N4 whiskers significantly optimized the interface and improved the performance of the composites. [ABSTRACT FROM AUTHOR]

The service conditions of high temperature and heavy load of aero-engine require high-temperature self-lubricating composites with high strength, low wear and long life. Hence, the high-level objective of this study is to regulate the interface between the substrate and hexagonal boron nitride (h-BN) lubricant in GH4169 nickel-based high-temperature self-lubricating composites to improve the interfacial bonding strength and the overall performance. Electroless plating method was adopted to coat nickel on h-BN, and the dense high-temperature self-lubricating composites were fabricated through hot-pressing sintering. The effects of nickel coating on h-BN on the microstructure, mechanical properties and high-temperature tribological behaviors of composites were analyzed in detail, and the lubrication mechanism was also elucidated. The results illustrate the Ni@h-BN/GH4169 composites with addition of chemically modified lubricant particles have excellent mechanical properties and lubrication and wear reduction properties, compared to h-BN/GH4169 composites. This is mainly due to the introduction of nickel coating contributed to the distribution uniformity of h-BN in the matrix, and the wettability between h-BN and the substrate together with interfacial bonding strength were enhanced as well. This work provides an insight to overcome the challenges facing the technology when using GH4169 nickel-based self-lubricating composites in manufacturing of mechanical components in aerospace. [ABSTRACT FROM AUTHOR]

The conducted work investigates the correlation between toughness characteristics and metal volume fraction in Fiber Metal Laminates (FMLs) subjected to tensile loads. Aerospace grade Al 7075-T6 was utilized as the varying metal alloy in the study. The metal alloy was combined with glass and carbon fiber layers to create different configurations of FMLs with varying stacking sequences. For better adhesion between metal and composite parts, aluminum layers were etched with sodium hydroxide and chromic-sulfuric acid solutions. The laminate sheets were prepared using the hand layup method which was followed by a vacuum bagging process. Specimens were cut and tested as per ASTM standard. Results of the experimentation showed that the aluminum volume fraction is directly related to the failure strain and modulus of toughness, however, inversely proportional to the stiffness characteristics of the laminates. The highest improvement of 111% in toughness parameter in comparison to pure composite laminate was reported. Finally, a comprehensive analysis on the type of fracture behavior in comparison to classical laminate theory was critically discussed. [ABSTRACT FROM AUTHOR]

The effect of surface treatments on hot-pressed GLARE 3/2 laminates included AA6061-T6 is evaluated in this paper. Sandpapering, degreasing and both degreasing and sandpapering are applied on AA6061-T6 sheets in order to contribute the improvement of the interlaminar shear strength (ILSS). The three-point bending tests are carried out by using two different span length-to-specimen thickness ratios (S/h) to examine also the effect of shear and bending on deformation and failure characteristics. Strength values and failure modes are obtained for both S/h ratios and all surface treatment types. Load-displacement and stress-displacement curves are evaluated. The results show that the maximum shear strength values for surface-treated laminates are increased by between 29% and 37% against untreated one. It is observed that the strength values and failure modes of all surface-treated GLARE laminates are influenced by an increase in the S/h ratio from 4.0 to 10.0 because of the increase in bending effect against shear. [ABSTRACT FROM AUTHOR]

Metal-matrix composites (MMCs), especially the novel carbon materials such as graphene (Gr), carbon nanotubes (CNTs) and diamond, reinforced MMCs, have received increasing attention from academia and industry due to their potential excellent properties. In carbon reinforced MMCs, the interface, as the 'bridge' between the matrix and the reinforcement, has great influence on the transfer of stress, thermal and electrical conductivity, and plays an important role to determine the properties of the composites. The structure and properties of interface between the carbon and metal matrix can be designed and enhanced. This paper summarizes the important research progress on the interfacial structure optimization method for carbon reinforced MMCs, and discussed the mechanism of the carbon/metal interface on the properties of the composites. Finally, the problems and development of the interface of carbon reinforced MMCs are prospected. [ABSTRACT FROM AUTHOR]

Parallel to the rapid technological developments in the electronics industry, electromagnetic (EM) interference protection has gained importance both daily and in all sectoral areas. Thermoplastic composites, which are widely used in electronic devices and vehicles, are becoming more popular due to their recyclability, superior mechanical/physical properties, the processability of complex shapes, and also blendability with various reinforcement materials compared to thermoset composites, and there has been an increasing demand for thermoplastic composites to have EM interference shielding properties. In this study, thermoplastic composites reinforced with carbon and metal hybrid filler systems produced by various production methods were investigated. Interfacial interactions of fillers and matrices were investigated by revealing synergistic EM interference shielding mechanisms. The effects of manufacturing processes, filler ratios, as well as the morphology of composites on EM interference shielding have been extensively discussed. The problems and limitations encountered in the production of EM interference shielding composites and the solution methods developed are emphasized. It is thought that this study will be a guiding resource for both academic and commercial studies. [ABSTRACT FROM AUTHOR]

The use of carbon fibres is being explored in synchronous belts due to their excellent mechanical properties, chemical and dimensional stability. However, poor adhesion between fibres and the common rubber-fibre adhesive resorcinol-formaldehyde-latex (RFL) compromises load transfer between these constituents. We examined the influence of surface characteristics of commercial glass and carbon fibres, such as fibre surface chemistry, energy and area on carbon fibre-RFL matrix adhesion in model single fibre composites. Fibres with higher surface oxygen content and thus more polar functional groups resulting in a higher surface energy exhibited better adhesion to RFL. Fibre adhesion behaviour to RFL can be ranked using the aspect ratio of the fibre diameter to the critical fragment length as assessed by single fibre fragmentation tests, however, accurate interfacial shear strength values cannot be obtained using the Kelly-Tyson model due to statistical limitations in the treatment of single fibre tensile properties. Our results provide insight into factors affecting fibre-RFL adhesion and identified commercial T700GC-31E carbon fibres as candidates for improved fibre-matrix adhesion for the production of more robust synchronous belts. [ABSTRACT FROM AUTHOR]

No doubt, composite technology is fast growing with an increase in research efforts around the world and with many academic interests consisting of breath-taking innovations in polymer science. Herein, the primary determinants of fiber/filler-matrix/composite properties are discussed viz-a-viz dispersion of reinforcing fibers, interfacial adhesion between matrix/fibers, and surface treatment methods for fibers in composite fabrication. Both thermoplastic and thermoset composites are discussed with much-focused discussion on the biodegradable and environmentally friendly PLA polymer matrix adhesion with filler/fibers. Since achieving enhanced mechanical properties of both thermoset and thermoplastic matrices involves reinforcement with both micro and nanofiller and, in many cases, with natural fibers, addressing the major issue of compatibilising the hydrophilic fiber with the hydrophobic polymer becomes more imperative. Beginning the discussion with a brief on adhesion and its mechanisms with polymer/matrix interaction, it further looked at key surface modification techniques with organic acids to promote dispersion in organic solvents and hydrophobic polymers to enhance interfacial adhesion. The last section offered recommendations with regards to 100% green composite system, with the possibility of achieving fiber/matrix compatibility with zero chemical consumption and fabrication of new materials whose properties are compatible without coupling and surface treatment of reinforcing fibers. [ABSTRACT FROM AUTHOR]

In this study, unidirectional flax fabrics were used to reinforce poly(lactic acid) (PLA). Flax/PLA composites were produced by thermo-compression using as-received flax fibers and titanium dioxide (TiO2) coated flax fibers. The aim was to investigate the effect of annealing temperature and time, under quiescent or mechanical stress conditions, on the microstructure, interfacial adhesion, crystallization, and mechanical properties of composites. Results showed significant differences between oxidized-TiO2-coated flax fibers/PLA composites (oxi-TiO2-C) and as-received flax fibers/PLA composites (AR-C). Indeed, above the glass transition temperature (Tg) of PLA, the storage modulus (E') of both composites significantly increased due to PLA crystallization. However, once E' reached a maximum value, composites with treated flax fibers leveled off while the E' of composites with untreated flax fibers dropped drastically. This peculiar result was explained by a partial destruction or damage of AR-C interface during PLA crystal growth. This phenomenon was not observed with oxi-TiO2-C, suggesting a good interfacial adhesion. Despite the presence of a trans-crystalline layer for both samples, it was shown that TiO2 coating of flax fibers strengthened the adhesion between flax fibers and the trans-crystalline structure. Interlaminar shear strength measurements revealed a 15% increase in the interfacial strength. [ABSTRACT FROM AUTHOR]

In this study, a novel structure of layered Ti-B4C/AA6061 composite with different B4C particles contents was designed and fabricated by pulse current sintering, and its microstructure and mechanical properties were investigated. It is found that the heterogeneous interface bonds well without voids and cracks and the B4C particles exhibit a homogenous distribution in AA6061 matrix. The intermetallic compounds (TixAly) are observed with a thickness of about 1.5 µm between Ti and B4C/AA6061 layers. The yield strength, ultimate tensile strength and elongation to fracture of the layered Ti-B4C/AA6061 composite are obviously enhanced. In addition, the Ti layers and the B4C particles embedded in the matrix play an important role in strengthening mechanisms of the layered composite, and the crack propagation is constrained by layered structure. [ABSTRACT FROM AUTHOR]

A kind of novel sustainable mycelium/cotton stalk composite were prepared in laboratory by growing white rot fungus of Ganoderma lucidum on cotton stalk and stored in a block mold followed by hot-pressing process. To improve the mechanical properties, the composites were, respectively, subject to water immersion prior to hot-pressing at various water uptake (20%, 30%, 40% and 50%). The mechanical properties including flexural and internal bonding properties were tested. The results showed that with increasing water uptake, the mechanical properties of the composites increased at first after reaching the maximum at water uptake of 30 wt% in accordance with the saturation point of cotton stalk. Therefore, the water contributed to the good interface between mycelium and cotton stalk particles, where the flexural and internal bonding strength met the standard for non-load bearing particleboard listed in ANSI A208.1–2016. However, at water uptake higher than 30 wt%, no further improvement occurred due to the excessive water located in cell lumen rather than in the cell wall. [ABSTRACT FROM AUTHOR]

In this work, short carbon fibers were first surface-grafted with various amounts of epoxy terminated hyperbranched polymers, and then utilized as reinforcing phases in various thermosetting polymeric blends composed of dicyanate ester of bisphenol-A (DCBA) and bisphenol-A based benzoxazine (BA-a) resins. The Fourier Transform Infrared Spectroscopy (FTIR) test validated the surface modification of the short fibers and confirmed the reaction between the coated fibers and the DCBA/BA-a resin blend. The composites' mechanical properties were evaluated and the obtained results revealed that at the maximum fiber loadings, the bending strength and modulus as well as the impact strength were identified to be 217.8 MPa, 7.1 GPa, and 18.4 kJ/m2, respectively. The scanning electron microscope (SEM) analysis established that the enhancements were basically attributed to the good dispersion and adhesion of the coated carbon fibers within the resin matrix. [ABSTRACT FROM AUTHOR]

Ti/Al laminated composite fabricated by explosive welding has received widespread attention due to their potential in achieving excellent performance. However, investigations on the crack evolution and fracture behavior were still limited. In this paper, the morphology and elemental distribution of the bonding interface were investigated. And the crack initiation and propagation of Ti/Al laminated composite was investigated by in-situ tensile test. It is shown that local melted zone (LMZ) was formed along the wavy interface, which was mainly consisted of TiAl2 + TiAl3 intermetallic compounds. The brittle intermetallic compounds on the LMZs are places where cracks initiate. As the internal stress accumulation, cracks generate at the tip of the wavy interface where the Ti layer is thinnest, and they locally form delamination along the interface. Subsequently, the crack tip is released from the Ti layer, leading to a catastrophic fracture to the whole Ti layer. Finally, the crack propagates to the Al layer until the material eventually fractured. [ABSTRACT FROM AUTHOR]

In this study, Polypropylene (PP) reinforced by nanocellulose/attapulgite composites (NCC/AT) was prepared. The mechanical properties and aging resistance of modified PP were studied. The morphology of modified PP was characterized by Scanning electron microscopy (SEM). The structure between NCC and AT was detected by Fourier transform infrared spectroscopy (FTIR). The proportion of NCC and AT on the mechanical properties of modified PP was investigated. The effect of the content of NCC/AT composites on the mechanical properties and aging resistance of modified PP were investigated. The results revealed that NCC/AT composite materials were prepared, and uniformly dispersed in the PP matrix. When the ratio of NCC and AT was 100:3 (m1/m2), the tensile strength and impact strength of modified PP were 32.85 MPa and 21.61 J/m, respectively. In addition, the tensile strength of modified PP with 3 wt% NCC/AT composites increased by 14.7% compared with pure PP. After 15 days of thermal aging, the retention rate of the tensile strength of modified PP was 98.81%, which was 5.16% higher than that of pure PP. The retention rate of impact strength of modified PP was 95.05%, which was 56.59% greater than that of pure PP. [ABSTRACT FROM AUTHOR]

AlN/AgNPs/epoxy composites were fabricated successfully, and the thermal conductivity and the dielectric properties of the composites were investigated. The thermal conductivity of the AlN/AgNPs/epoxy composites was enhanced compared with the pure epoxy resin and the AlN/epoxy composites. The samples containing 40 wt% AlN/AgNPs exhibit the highest thermal conductivity (4.72 Wm−1K−1), which is as high as 22 times to that of neat epoxy resin. We attribute the enhanced thermal conductivity to the silver nanoparticles, which can 'bridge' the adjacent fillers in the matrix and form a more effective heat-conducting network. A fabrication route for epoxy composites filled with AlN decorated with silver nanoparticles and their corresponding thermal conductivities. [ABSTRACT FROM AUTHOR]

In rubber-toughened mixtures, the rubber is intended to dissipate the stress so that the blend shows ductility and plastic deformation. But poor interfacial adhesions, high interfacial tension, differences in polarity and structure between rubber and thermoplastic phases are the main reasons for incompatibility of these systems. The present work deals with the study of nanocomposites based on poly(styrene–acrylonitrile) (SAN) and ethylene–propylene–diene monomer (EPDM) blends with and without an organically modified montmorillonite (O-Mmt) filler as a compatibilizer. These blends are prepared by melt compounding using an internal mixer (Brabender). The dispersion of O-Mmt layers and the morphology of the nanocomposites, were determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The effects of EPDM amount and O-Mmt on the rheological, mechanical properties and thermal stability of the nanocomposites were also investigated. All molten blends containing nanoclay particles exhibit higher viscosity than those of neat SAN/EPDM binary blends. XRD patterns and SEM examination revealed that silicate layers were exfoliated and well dispersed in the blend and the presence of nanoclay has reduced the domain size of EPDM phase. Thermogravimetric analysis (TGA) results showed that the incorporation both of EPDM and O-Mmt increased the thermal stability of SAN material. In binary blends, addition of EPDM has reduced the stiffness and tensile strength; however it improved the impact toughness and ductility of SAN. But, on adding nanoclay, results display the reverse trend: the stiffness of SAN/EPDM/O-Mmt nanocomposites increases in comparison to neat SAN and SAN/EPDM blends. [ABSTRACT FROM AUTHOR]

This paper reports on a study of highly filled composites of polypropylene (PP) and 75 and 85% by weight of oil palm mesocarp fiber (OPF) with and without coupling agent, maleic anhydride-grafted poly (styrene-ethylene/butadiene styrene) (SEBS-MA) and a maleated polypropylene (MAPP). Composites were prepared using a thermokinetic mixer for blending followed by hot pressing. The thermal and mechanical behavior of these composites was investigated by flexural and impact testing and scanning electron microscopy (SEM). Dynamic mechanical analysis (DMA) was also used to study the properties. The MAPP improve the flexural modulus and flexural strength of the composites with 75 and 85wt% of oil palm fiber while SEBS-MA improved the impact strength of the composites. By SEM it was possible to observe some voids, pull out and debonding in the polypropylene, and allowing the observation of level of adhesion between the fiber and matrix. DMTA showed a decrease in storage modulus when high amounts of fiber were added to polypropylene, however, the presence of the SEBS-MA and MAPP increased the storage modulus. This study looks into the effect of MAH modification on the compatibility of OPF and PP, gives a broad overview of an initial study of these new materials. [ABSTRACT FROM AUTHOR]

Styrene-ethylene-butadiene-styrene (SEBS) copolymer grafted graphene oxide/epoxy (SEBS-g-GO/EP) nanocomposites were successfully prepared by modifying the curing agents of epoxy resin. To enhance the dispersity of graphene oxide (GO) itself and improve the compatibility between GO and polymer matrix, SEBS-g-GO was prepared via solution mixing technique, amination and following reaction with maleic anhydride grafted SEBS (SEBS-g-MAH), resulting in grafting rate 49 wt%. A series of characterization methods included the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscope (SEM) and transmission electron microscopic (TEM) were used to confirm the grafting of SEBS onto GO. The effects of SEBS-g-GO on epoxy resin (EP) nanocomposites were investigated by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile, flexural and impact test. The results showed that SEBS-g-GO could be uniformly dispersed in the epoxy resin matrix. The tensile strength, flexural modulus and impact strength of epoxy nanocomposite with 0.3 wt% SEBS-g-GO are 109.05%, 51.61% and 139.32% higher than that of pure epoxy resin, respectively. [ABSTRACT FROM AUTHOR]

This paper reviews literatures and information on Abaca fibers (Musa textilis Nee) as reinforcing material for aerospace composite materials. Characterization of Abaca as well properties of Abaca reinforced composites and its applications were discussed. Therefore, challenges and future works for Abaca Reinforced composites were explored. Studies reveal that Abaca fiber pre-treatment helps in improving the mechanical properties of the composite. In addition, there have been efforts in combining Abaca fibers to existing mixture of synthetic composites to improve its mechanical properties and environmental performance. The future of Abaca is seen as one of the potent sources of reinforcing fiber for various material construction including aerospace materials. [ABSTRACT FROM AUTHOR]

Carbon-based composites bring great promise for various practical applications ranging from aviation industry to advanced biomedical sensors. The interface chemistry and the ultimate conductivity of these composites are responsible for their functional applicability. The interfaces can be modified by various chemical and physical techniques. This article reviews the synthesis methods of carbon composites and discusses how the interface properties dictate their applicability. [ABSTRACT FROM AUTHOR]

The effects of multiwalled carbon nanotubes (MWCNTs) modified by silane coupling agent (Trademark in china was KH570) and lactide (LA) on the properties of poly(lactic acid) (PLA) composites were investigated in this paper. The Scanning electronic microscopy (SEM) images showed that MWCNTs modified by both KH570 and LA, which constructed the MWCNTs-KH570-PLA nanocapsules, owned the best performances to toughen PLA. These nanocapsules were developed by solid multilayered interfaces and efficiently enhanced tnced the interfacial adhesion between PLA and MWCNTs. Polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis further verified that modified MWCNTs refined the PLA grain size and improved its crystallization. Moreover, observed by thermogravimetry (TG), the thermal stability of PLA was also improved. Then it could be drawn the conclusion that among these modified MWCNTs, MWCNTs-KH570-PLA nanocapsule was the best in toughening PLA, and the tensile strength of MWCNTs-KH570-PLA/PLA composite rose by 39.97% and its impact strength by 51.61%. [ABSTRACT FROM AUTHOR]

The segregated graphene oxide(GO)/ultra-high-molecular-weight polyethylene (UHMWPE) composite films with various interfacial adhesion property were prepared by mechanical blending method from UHMWPE, GO, dodecyl amine (DA) functionalized graphene oxide(DA–GO) or uniform DA–GO/high density polyethylene (DA–GO/HDPE) powder. The results of XRD and XPS indicated that DA chain was successfully grafted onto GO sheets via a chemical method, which enhanced the interfacial adhesion between UHMWPE particles and GO sheets. The characterizations of POM and SEM proved that good segregated structure was only obtained in DA–GO/UHMWPE or DA–GO/HDPE/UHMWPE composite. Strong interfacial adhesion between fillers and matrix exhibits positive effect on gas barrier property. Compared to the GO/UHMWPE composite film, dramatic decrease in O2permeability coefficient by 42.2 and 48.1%, from 15.4 × 10−14to 8.9 × 10−14and 8.0 × 10−14 cm3 cm cm−2 s−1 Pa−1, is achieved upon the addition of only 0.5 wt% fillers, respectively. The DSC results demonstrated that the enhanced gas barrier performance was ascribed to the strong interfacial adhesion between DA–GO/HDPE and UHWMPE matrix, rather than the crystallinity of UHWMPE matrix. Additionally, the decrease in UHMWPE particle size might be conducive to improving the gas barrier property of composite films due to the formation of more isolation layers perpendicular to the film plane. [ABSTRACT FROM AUTHOR]

The effects of three silane coupling agents, triethoxy(octyl)silane (TEOS), bis[3-(triethoxysilyl)propyl]disulfide (TESPD), and bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT) on the filler-rubber interaction, crosslink density and crosslink structure of the silica-filled solution styrene butadiene rubber (SSBR) vulcanizates were studied. High dispersion silica, 7000GR, was used as the filler, and the loading range was varied from 0 to 60 phr. Crosslink density was measured by the swelling method. Experimental results showed that Kraus plot can be applicable to the silica-filled SSBR vulcanizates to separate filler-rubber interaction from the measured swelling data. Filler-rubber interaction increased by increasing sulfur rank in the silane as TEOS < Silica without silanes < TESPD < TESPT. Sulfurless silane, i.e. TEOS, only worked as a covering agent for hydrophobating silica surface. Silica without silane show high filler-rubber interaction than TEOS system because chain-end functionalized SSBR was used in this study. Unfilled system showed similar amounts of poly, di, and mono-sulfidic crosslinks. On the contrary to this, all of the silica-filled vulcanizates showed high mono-sulfide contents due to longer cure time. [ABSTRACT FROM AUTHOR]

By adding magnetic powders into matrix material, it has been proved to be a creative approach to improve tribological properties of brake materials. In this paper, a novel magnetic brake material with Nd–Fe–B and nano-Fe3O4was developed, and the influential mechanism of these two magnetic powders and their content on the friction and wear performance was deeply discussed. Firstly, some experiments were carried out to investigate the tribological performance and influential mechanisms of four groups of brake pad samples with different magnetic powders. Furthermore, based on these results, further experiments for investigating the influence that Nd–Fe–B contents have on the tribological properties were conducted. According to the theoretical analysis about experiments, it was concluded that nano-Fe3O4is beneficial to promote the formation of friction film and has certain lubricant effects. However, Nd–Fe–B has double effects on the formation of friction film. It will have positive effects when its content is less than a certain value. Otherwise, it will destroy the structure of friction film. Conclusively, it is believed that this study will be significantly valuable and meaningful for developing new brake materials and improving safety reliability of mechanical brakes. [ABSTRACT FROM AUTHOR]

ZnO was firstly coated on the surface of aluminum borate whiskers (ABOw) by sol–gel. Then, ZnO-coated ABOw was added into soybean slurry to make a preform with low volume fraction and the preform was sintered at high temperatures to obtain a sufficient strength. ABOw reinforced aluminum composite (ABOw/Al) was fabricated by squeeze casting. Interfacial microstructures, tensile properties, and fracture mechanisms of the ABOw/Al composite were investigated. The results show that the coating of ABOw and the addition of soybean sacrificial filler can effectively decrease the volume fraction of whiskers in the composite. The ultimate tensile strength of composite has not changed much with the decrease of whiskers volume fraction in the composite. However, the elongation to fracture of the composite evidently increases and it can reach 11.1% at room temperature. [ABSTRACT FROM AUTHOR]

The most important practical application of graphene nanoplatelets (GNPs) would be as nanofillers for polymer nanocomposites. However, the modification of GNPs is needed to improve the interfacial adhesion between GNPs and a polymer matrix. Therefore, in this study, the alkylation of GNPs by dodecylamine was carried out via chemical reactions between the amine groups of the alkyl amine and the carboxyl and epoxy groups of the oxidized GNPs’ surfaces. The dodecylation of the GNPs was confirmed by FTIR and TGA. The TGA data showed that the dodecyl-GNPs comprised alkyl groups 2.4%. Polypropylene nanocomposites with the dodecyl-GNPs were prepared in a platy shape by melt-blending followed by compression molding. The mechanical and thermal properties of the nanocomposites were measured by UTM, izod impact tester, DSC and DMA. Compared to the neat PP sample, the flexural modulus, flexural strength and impact strength of the PP nanocomposite with the dodecyl-GNPs 0.5 phr were increased by 38, 4 and 34% respectively. The fracture surfaces’ images of the nanocomposites taken by SEM showed that the dodecylation of the GNPs improved the interfacial adhesion between the GNPs and the PP matrix. [ABSTRACT FROM AUTHOR]

Butyl rubber (IIR)/hydrophobically modified graphene oxide (GO) (HG) nanocomposites were prepared via shear-induced compounding. Hydrophilic GO was synthesized through the chemical oxidation of graphite (GP) and modified hydrophobically by octadecylamine which has a hydrophobic long alkyl chain. The obtained HG was characterized by Fourier transform infrared and wide-angle X-ray diffraction (WAXD) patterns. It was well dispersed in toluene for more than 30 days under stationary condition. The IIR/HG nanocomposites were prepared by the shear mixing process and followed by thermal vulcanization process through compression molding. Their properties were studied using oscillating disk rheometer, universal testing machine, differential scanning calorimetry, thermogravimetric analysis, WAXD patterns, and scanning electron microscope analysis. The hydrophobic HG was dispersed at the nanoscale within IIR matrix, and the resulting nanocomposites had significantly reduced curing time. The overall tensile properties were enhanced. [ABSTRACT FROM PUBLISHER]

The fiber metal laminates (FML), consisting of carbon fiber reinforced polymer prepregs and magnesium alloys sheets, were introduced, and the Mode I (peel) and Mode II (shear) interlaminar fracture toughness of the FMLs were investigated. The results show that the Mode I interlaminar toughness (0.23 kJ/m2) of the FMLs is much lower than the Mode II interlaminar toughness (5.81 kJ/m2), due to the fact that the effects of mechanical interlock to hinder crack propagates is smaller under Mode I loading conditions than under Mode II. The FMLs mainly show adhesive failure and interfacial failure under Mode I loading conditions, while for Mode II loading, it exhibits a degree of epoxy cohesive failure except the adhesive failure and interfacial failure. [ABSTRACT FROM PUBLISHER]

This paper aims to presents the investigations made on the effect of impact response of chopped glass fiber–epoxy nanocomposite laminates subjected to low velocity impact using instrumented falling weight impact tests. The laminates were prepared using six layers of chopped strand mat with density of 610 gsm with epoxy resin and nanoclay content varied from 1, 3, and 5 wt%, by hand lay-up method. The nanoclay was dispersed into the epoxy by high shear mixing process in order to obtained uniform distribution of individual nanoclay. Laminates were impacted at constant mass with different impact energies. During these low velocity impact tests, the maximum load, absorbed energy, and deflection at peak load were recorded. It was observed that by dispersion of nanoclay as reinforcement, there was significant improvement in load carrying capacity and energy absorption. When a small amount of nanoclay (1 wt%) was added into the epoxy, the maximum load was enhanced by 20%. The presence of stiffer nanoclay significantly reduced the surface cracks propagation and controlled delamination area. Scanning electron microscopy was performed to characterize the damage progression. [ABSTRACT FROM PUBLISHER]

Cellulosic substances in polymer matrices are immiscible and non-dispersive because of mismatch between their surface properties. In order to fabricate a natural fiber-reinforced plastic, hydrophilic cellulosic substances should be modified to hydrophobicity to make it miscible and dispersible to polymer matrices. Herein, this work shows potential application of vapor-phase-assisted surface treatment as a new modification approach for cellulosic substances. Cellulosic substances were modified to improve the compatibility in the polymer matrix. The modified cellulose substrates were characterized by Fourier transform infrared spectrometer spectroscopy, thermogravimetric analysis, and scanning electron microscope, and the resulting shows the grafting polymer on cellulosic substances indeed. To more enhance compatibility in polymer matrix, grafting of the methacryloyl groups on cellulose substance was prepared through gaseous methacrylic anhydride on cellulose surface, and then higher modified cellulose substance was carried out with vapor-phase graft polymerization of methyl methacrylate finally. The vapor-phase-assisted surface treatments could highly modify the cellulose surface compared to conventional method in liquid process. [ABSTRACT FROM PUBLISHER]

In this study, nano α-alumina particles were synthesized by a sol–gel method using aqueous solutions of aluminum isopropoxide and 0.5 M aluminum nitrate. 1/3-benzene disoulfonic acid disodium salt (SDBS) and fluoride were used as surfactant stabilizing agent and additive, respectively. Results indicated that the finest size for nonagglomerated nanoalumina particles (15–20 nm) was achieved at 950 °C. The next part was about preparing PP nanocomposite containing nano α-Al2O3particles. Mechanical tests, such as tensile, flexural, and impact tests showed that mechanical properties of the composite were enhanced by addition of nano α-Al2O3particles and dispersant to the polymer. However, higher concentration of nano α-Al2O3loading resulted in reduction of those mechanical properties, which could be due to agglomeration of nano α-Al2O3particles. Transmission and scanning electron microscopic observations of the nanocomposites also showed that fracture surface became more roughened by increasing the content of filler loading from 1 to 4% wt. [ABSTRACT FROM PUBLISHER]

The dry sliding wear characteristics of glass-epoxy (G-E), graphite-filled G-E and functionally graded graphite-filled G-E composites were investigated using pin-on-disc test rig. The specific wear rate was determined as a function of applied load, sliding velocity and sliding distance. The results revealed that the specific wear rate increases in all the tested composites with increasing wear parameter. But, the admirable wear resistance was obtained with functionally graded graphite-filled G-E composite. The scanning electron microscope studies of worn-out surfaces support the involved wear mechanisms and are well indicated in the worn-out surface features such as matrix wear, fibre exposure, fibre breakage, fibre and matrix deboning, microcracking, debris formation, fibre cracking and removal of fibres. [ABSTRACT FROM PUBLISHER]

The present work concentrates on the effect of epoxy surface treatment and twisting on mechanical and interfacial properties of unidirectional (UD) fiber reinforced thermoplastic composites. The purpose of study is to find out whether the mechanical and interfacial properties of composites can be improved by surface treatment and twisting or not. In all specimens, PA 66 was commingled with aramid (AR) yarn. AR was used as reinforcement and PA 66 was used as resin yarn. The different weight percent of epoxy, such as 3, 6, and 9wt % and twisting such as 0, 20, 40, 60, 80, and 100 tpm, were applied on the commingled yarns. After fabrication of UD composites with commingled yarns, the mechanical properties of laminates were investigated by conducting tensile and three-point bending test. Consequently, the optimum twisting number and wt% of epoxy surface treatment was found. By increasing twisting until an optimum level, the tensile strength of fiber bundle as well as tensile and bending strength of UD composite increased. The interfacial properties of composites with various twisting levels did not change. [ABSTRACT FROM PUBLISHER]

A continuous atmospheric plasma (AP) polymerisation method was developed, using an acrylonitrile precursor, to enhance the adhesion of carbon fibres to an elastomeric resorcinol formaldehyde latex (RFL) matrix. Different processing speeds, corresponding to different residence times in the afterglow zone of the plasma jet, and precursor dosing rates were explored to optimise the treatment. X-ray photoelectron spectroscopy showed that carbon fibres were successfully functionalised in this process. The higher hydrophilicity and better adhesion to RFL was mainly attributed to the introduction of polar amide and hydroxyl groups introduced onto carbon fibre surfaces. Single fibre tensile tests confirmed that AP treatment did not affect the bulk mechanical properties of carbon fibres. The adhesion behaviour between carbon fibres and RFL was characterised by single fibre fragmentation tests. The interfacial shear strength, as measure of practical adhesion, increased by 30% for the fibres exposed longest to the plasma. The plasma-treated carbon fibres were aged in ambient atmosphere for up to three months to determine the effect of storage on the adhesion between the fibres and RFL. After ageing, an 11% reduction of interfacial shear strength was observed. [ABSTRACT FROM PUBLISHER]

In this study, biocomposites were prepared by using an unsaturated polyester and Luong bamboo fibers (BFs). Fibers separated from bamboo body by mechanical method had size distribution mainly between 0.24 and 0.40 mm diameter and 1–2.5 cm length. Some factors having effect on properties of materials, such as fiber content, type, and concentration of coupling agents were also studied. As a result, composite materials showed good properties at 90 phr of BFs that were modified by 0.7% vinyl-functional silane coupling agent. [ABSTRACT FROM PUBLISHER]

Moderate carbon nanotubes (CNTs–Al) bond strength plays a key role in determining the mechanical and physical properties of the composite. Here, the effect of hot extrusion and heat treatment on the CNTs–Al reaction and their bond state were investigated in SiCw + CNTs/6061Al hybrid composites prepared by squeeze casting. The results show that the reaction activation energy between CNTs and molten 6061Al is slightly higher than that between CNTs and 2024Al. Reaction between CNTs and Al may also happen at temperature below solidus temperature of 6061Al. After the hot-extruded composite was heat-treated at 580 °C for 1 h, the composite shows enhanced tensile strength due to the improvement of interfacial bond strength between CNTs and Al. Fracture surface observation reveals that the improvement of the tensile strength is related to the enhancement of CNTs–Al bond strength. This demonstrates that controllable interfacial reaction may be adopted to introduce moderate interaction layer between CNTs and Al, and thus raise their bond strength. [ABSTRACT FROM PUBLISHER]

In this study, the adhesion between ethylene methyl acrylic (AEM) rubber and polyester fabric treated with double dip system was evaluated and the fatigue resistance of AEM rubber–polyester fabric composites was evaluated. When determined the latex of resorcinol-formaldehyde-latex solution having high compatibility with AEM rubber, chloroprene rubber latex where the cross-linking reaction was possible with amine cross-linking agent showed the highest bond strength in the adhesion of the AEM rubber–polyester fabric composites. The adhesion of AEM compound applying both RF-resin and hexamethoxymethylmelamine which are the adhesion promoters showed the increase of approximately 41.7% compared to the compound without applying them. The compound applying adhesion promoters and carbon black (10 phr)/silica (20 phr) showed the increased adhesion of approximately 21.7% than the compound applying adhesion promoter and carbon black (30 phr). The bond strength of the AEM rubber–polyester fabric composite was excellent when the least amount of cross-linking agent and accelerator were applied to the AEM compound. As the results of fatigue test, the compound with plasticizer and adhesion promoters showed lower accumulated crack length than the compound with adhesion promoters only, and the compound with adhesion promoter and carbon black/silica filler blend showed the lowest crack number and accumulated crack length than the above two compounds, so it can be judged that its fatigue resistance is superior. [ABSTRACT FROM PUBLISHER]

In this research, the adhesion between ethylene methyl acrylic (AEM) rubber and polyester fabric treated with isocyanate and the fatigue properties of the AEM rubber–polyester fabric composites were examined. Experiments were conducted according to the concentrations of isocyanate adhesive solution in order to determine the optimum concentration of the adhesive agent and the results showed that adhesion was the most superior when 14% solution was applied and this was also confirmed by Scanning electron microscope morphology. Moreover, the impregnated polyester fabric was treated at 120, 170, 200, and 230 °C and peel test was conducted in order to determine the optimum curing condition. The results showed that adhesion was the most superior when the polyester fabric was cured for 2 min at 230 °C. It was judged that this resulted from the network structure of isocyanate and the formation of carbodiimide structure at the curing temperature of 230 °C. Comparing to the fatigue properties of the rubber–fabric composites from single dip system and the double dip system, the crack number and the accumulated crack length, the crack propagation was lower when the double dip system was applied. This resulted from the flexibility of the interphase of the polyester fabric–AEM rubber composites by the application of resorcinol-formaldehyde-latex (RFL). [ABSTRACT FROM PUBLISHER]

The polyaniline (PANI) is a widely studied conducting polymer due to its application in several devices such as biosensor, gas sensor etc. Known methods to produce PANI composites may be essentially reduced to two distinct groups: synthetic methods based on aniline polymerization in the presence of or inside a matrix polymer, and blending methods to mix a previously prepared PANI with a matrix polymer. Poly (aniline-co-butyl 3-aminobenzoate) (ANI-co-BAB) and poly (aniline-co-ethyl 3-aminobenzoate) (ANI-co-EAB) are prepared as conducting copolymers in nanoscale by chemical oxidation method under ultrasonic irradiation. The different molar ratio of aniline to butyl 3-aminobenzoate and ethyl 3-aminobenzoate are used in the preparation of copolymers. Conductive nanocomposites based on ANI-co-BAB or ANI-co-EAB with poly (styrene-alt-maleic acid) (PSMAC), and polystyrene are prepared by solution blending method. The obtained conductive composites formed films with good homogeneity and flexibility. The conductivity of the obtained nanocomposites is measured with a four-probe method. The electrical conductivity of the composites (ANI-co-EAB)/PSMAC/PS and (ANI-co-BAB)/PSMAC/PS are 24 × 10−5 S cm−1and 31 × 10−5 S cm, respectively. Our results show that the (ANI-co-BAB)/PSMAC/PS composite has more conductivity than (ANI-co-EAB)/PSMAC/PS composite. The copolymers and composites in nanoscale are characterized by FT-IR and1H NMR spectral data. The surface morphology was studied using SEM analysis. Also, their grain size is measured using XRD studies. [ABSTRACT FROM PUBLISHER]

Strong reinforcing effects are observed when multiwall carbon nanotubes are incorporated in a styrene–butadiene copolymer. The good level of dispersion of carbon nanotubes in the host matrix that allows to take advantage of their high aspect ratio as well as their orienting capability under uniaxial extension, appear to be the main parameters for mechanical reinforcement. Atomic force microscopy carried out in the unstretched and stretched states has been shown to bring important insights for the understanding of the mechanical properties of the composites. [ABSTRACT FROM PUBLISHER]

High density polyethylene (HDPE)/poly (ethylene terephthalate) (PET) (90/10 wt.%) blends and HDPE/PET/multi-walled carbon nanotubes (MWCNTs) nanocomposites were prepared by melt mixing process, and the influence of MWCNTs on the mechanical and rheological properties of the nanocomposites was investigated. MWCNTs were added up to 5 wt.% in the HDPE/PET matrix. Transmission electron microscopy images reveal that the MWCNTs were homogeneously dispersed in the HDPE/PET matrix. Improvement of mechanical properties was observed by the addition of MWCNTs compared with HDPE/PET blends. Prominent increases in the complex viscosity and storage modulus of the nanocomposites were found with increasing MWCNT content. [ABSTRACT FROM PUBLISHER]

Hot-stage microscopy was used to characterise crystal growth at the interface between sisal fibre bundles and a polylactic acid (PLA) matrix in order to better understand the mechanical properties of sisal fibre–PLA composites. Cooling rates and crystallisation temperatures and times were varied to influence crystalline morphology at the interface. Single sisal fibre bundles were evaluated in their as received state or treated with 6 wt.% caustic soda solution for 48 h at room temperature. A microbond shear test was used to characterise the shear strength of the interface as a function of fibre surface treatment. These tests were performed on sisal fibre bundles carefully embedded in flat films of PLA supported on card mounts. Fibre bundles in a PLA matrix were cooled from 180 °C at rates from 2 to 9 °C/min and then crystallised isothermally. For as received fibre bundles uneven growth of PLA spherulites occurred at all cooling rates and crystallisation temperatures. For caustic soda treated fibres, uneven spherulitic growth was observed at crystallisation temperatures at and above 125 °C. In contrast, transcrystalline growth was observed for samples cooled to 120 °C at cooling rates from 2 to 6 °C/min and then allowed to crystallise. The microbond shear strengths of untreated and caustic soda treated fibre bundles were evaluated using Weibull statistics and the caustic soda treated fibres exhibited higher interfacial shear strengths in comparison to untreated fibres, reflecting the development of a transcrystalline layer at the fibre to matrix interface. [ABSTRACT FROM PUBLISHER]

The effect of organically modified montmorillonite (OMMT) and silane coupling agent on the abrasion resistance of SiO2-filled butadiene rubber (BR) vulcanizates has been investigated. Various amounts of OMMT are added into SiO2-filled BR vulcanizates. A silane coupling agent, bis-(3-triethoxysilyl propyl) tetrasulfide (Si69), is used to modify OMMT during the masterbatch preparation for evaluating the influence of surface treatment on the abrasion resistance. Incorporation of OMMT into BR results in deterioration of the abrasion resistance as compared to unfilled BR vulcanizate due to poor dispersion of OMMT and insufficient interfacial adhesion between OMMT and BR matrix. The use of Si69 improves dispersion of OMMT particles and rubber/OMMT adhesion, resulting in abrasion resistance enhancement of BR/OMMT vulcanizates. By using similar compounding conditions as those for BR/OMMT vulcanizate, nanodispersion of OMMT in BR/SiO2/OMMT vulcanizate has been achieved as judged by the high viscosity of the SiO2-filled BR compound. This improved dispersion leads to better abrasion resistance of the BR/SiO2/OMMT than that of the BR/SiO2composite. Utilization of Si69 slightly affects the DIN volume loss of BR/SiO2/OMMT vulcanizates and the abrasion pattern. [ABSTRACT FROM PUBLISHER]

Coir/silk fiber-reinforced polypropylene (PP) based unidirectional composites (40 wt.%) were manufactured by compression molding. Coir/silk fibers and PP sheets were treated with ultraviolet radiation at different intensities and then composites were fabricated. It was found that mechanical properties of irradiated silk/irradiated PP composites were found to increase significantly compared to the untreated ones and even higher than that of irradiated coir/irradiated PP composites. Soil degradation tests indicated that irradiated coir/irradiated PP composites significantly lost much of its mechanical properties, but irradiated silk/irradiated PP composites retained their strength of its original integrity. Scanning electron microscopy and water uptake of both types of composites were also investigated. [ABSTRACT FROM PUBLISHER]