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1.
This paper investigates the effect of sub‐micron size cenosphere filler and filler loading on mechanical and dry sliding wear property of polyester composites. Composites are fabricated by filling with 10 and 20 wt% of 800 and 200‐nm size of cenosphere filler particles. Neat polyester composite is also prepared for comparison analysis. Dry sliding wear test is conducted for these composites over a range of sliding distance with different sliding velocities and applied loads on a pin‐on‐disc wear test machine. Taguchi methodology and analysis of variance (ANOVA) is used to analyze the friction and wear characteristics of the composites. The artificial neural network (ANN) approach is implemented to the friction and wear data for corroboration. In this work, mechanical properties of composites such as hardness, tensile strength, tensile modulus, flexural strength, and compressive strength revealed that mechanical properties and wear resistance of the composites increase with a decrease in the particle size. The measured Young's moduli are comparable to standard theoretical prediction models. The morphology of worn composite specimens has been examined by scanning electron microscopy to understand the dominant wear mechanisms. Finally, optimal factor settings are determined using a genetic algorithm (GA). Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

2.
In this paper, different morphologies ZnO (disk‐like, rod‐like, and nanoparticles) were introduced into phenolic composite coatings to comparatively investigate the tribological properties. The structural and morphological characterization was conducted with Raman spectroscopy, X‐ray diffraction, and scanning electron microscopy. The tribological performances of composite coatings were evaluated using ring‐on‐block tester under dry condition at room temperature. Experimental results indicated that composite coatings filled with 1 wt% ZnO micro‐disks possessed the optimal tribological performances. It was attributed to the strong interfacial interaction between ZnO micro‐disks and phenolic matrix induced by their specific polar structure. Moreover, different loads and sliding speeds were employed to further evaluate the tribological performances of ZnO micro‐disks/phenolic composite coatings. The outcome revealed that ZnO micro‐disks were potential anti‐wear fillers under harsh condition.  相似文献   

3.
The unmodified and hexamethylene diisocyanate (HDI) modified TiO2 nanotubes, were used for fabricating TiO2 nanotubes (TiNTs)/polyurethane (PU) composite coating. The effects of applied load and sliding speed on the tribological behavior of the composite coating were investigated using a block-on-ring wear tester. Compared to the TiO2 nanotubes filled PU composite coating, the HDI modified TiO2 nanotubes (TiNTs-HDI) filled one had the lower friction coefficient and higher wear life under various applied loads and sliding speed. Scanning electron microscope (SEM) investigation showed that the TiNTs-HDI filled PU coating had smooth worn surface under given applied load and sliding speed, and a continuous and uniform transfer film formed on the surface of the counterpart ring, which helped to reduce the wear of the coating. The improvement in the tribological properties of TiNTs-HDI/PU composite coating might due to an improvement in interfacial adhesion between TiNTs and PU after HDI treatment. The strong interfacial coupling of the composite coating made TiNTs-HDI not easy to detach from the PU matrix, and prevented the rubbing-off of PU composite coating, accordingly improved the friction and wear properties of the composite coating.  相似文献   

4.
One‐layer and two‐layer nano‐TiO2 thin films were prepared on the surface of common glass by sol–gel processing. Water contact angle, surface morphology, tribological properties of the films before and after ultraviolet (UV) irradiation were investigated using DSA100 drop shape analyzer, scanning probe microscopy (SPM), SEM and universal micro‐materials tester (second generation) (UMT‐2MT) friction and wear tester, respectively. The stored films markedly resumed their hydrophilicity after UV irradiation. But UV irradiation worsened tribological properties of the films. After the film was irradiated by UV, the friction coefficient between the film and GCr15 steel ball increased about 10–50% and its wear life shortened about 20–90%. Abrasive wear, brittle break and adherence wear are the failure mechanisms of nano‐TiO2 thin films. It was believed that UV irradiation increased surface energy of the film and then aggravated adherence wear of the film at initial stage of friction process leading to severe brittle fracture and abrasive wear. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

5.
In this study, we investigated the influence of epoxy resin treatment on the mechanical and tribological properties of hemp fiber (HF)-reinforced plant-derived polyamide 1010 (PA1010) biomass composites. HFs were surface-treated using four types of surface treatment methods: (a) alkaline treatment using sodium chlorite (NaClO2) solution, (b) surface treatment using epoxy resin (EP) solution after NaClO2 alkaline treatment, (c) surface treatment using an ureidosilane coupling agent after NaClO2 alkaline treatment (NaClO2 + A-1160), and (d) surface treatment using epoxy resin solution after the (c) surface treatment (NaClO2 + A-1160 + EP). The HF/PA1010 biomass composites were extruded using a twin-screw extruder and injection-molded. Their mechanical properties, such as tensile, bending, and dynamic mechanical properties, and tribological properties were evaluated by the ring-on-plate-type sliding wear test. The strength, modulus, specific wear rate, and limiting pv value of HF/PA1010 biomass composites improved with surface treatment using epoxy resin (NaClO2 + A-1160 + EP). In particular, the bending modulus of NaClO2 + A-1160 + EP improved by 48% more than that of NaClO2, and the specific wear rate of NaClO2 + A-1160 + EP was one-third that of NaClO2. This may be attributed to the change in the internal microstructure of the composites, such as the interfacial interaction between HF and PA1010 and fiber dispersion. As a result, the mode of friction and wear mechanism of these biomass composites also changed.  相似文献   

6.
《先进技术聚合物》2018,29(1):347-354
This study investigates the effect of multiwalled carbon nanotubes (MWCNTs) content on rheological, mechanical, and EMI shielding properties in Ka band (26.5‐40 GHz) of poly (ether‐ketone) [PEK] prepared by melt compounding using twin screw extruder. Transmission electron microscopy (TEM) and field emission gun scanning electron microscopy (FEG‐SEM) studies were adopted to identify dispersion of nanotubes in PEK matrix. TEM and SEM images showed uniform dispersion of MWCNTs in PEK/MWCNT composites even at loading of 5 wt%. The rheological studies showed that the material experiences viscous (fluid) to elastic (solid) transition at 1 wt% loading beyond which nanotubes form continuous network throughout the matrix which in turn promotes reinforcement. Additionally, Van‐Gurp Palmen plot (phase angle vs complex modulus) and values of damping factor further confirm that the material undergoes viscous to elastic transition at 1 wt% loading. This reinforcement effect of nanotubes is reflected in enhanced mechanical properties (flexural strength and flexural modulus). Flexural strength and flexural modulus of PEK showed an increment of 17% upon incorporation of 5 wt% of MWCNTs. Total shielding effectiveness (SET) of −38 dB with very high shielding effectiveness due to absorption (SEA ~ −34 dB) was observed at 5 wt% loading of MWCNTs in PEK matrix in the frequency range of 26.5‐40 GHz (Ka band).  相似文献   

7.
This research works with the optimal design of marble dust-filled polymer composites using a multi-criteria decision-making (MCDM) technique. Polylactic acid (PLA) and recycled polyethylene terephthalate (rPET)-based composites containing 0, 5, 10, and 20 wt% of marble dust were developed and evaluated for various physicomechanical and wear properties. The results showed that the incorporation of marble dust improved the modulus and hardness of both PLA and rPET. Moreover, a marginal improvement in flexural strength was noted while the tensile and impact strength of the matrices were deteriorating due to marble dust addition. The outcomes of wear analysis demonstrated an improvement in wear resistance up until 10 wt% filler reinforcement, after which the incidence of dust particles peeling off from the matrix was observed, thereby reducing its efficiency. The best tensile modulus of 3.23 GPa, flexural modulus of 4.39 GPa, and hardness of 83.95 Shore D were obtained for 20 wt% marble dust-filled PLA composites. The lowest density of 1.24 g/cc and the highest tensile strength of 57.94 MPa were recorded for neat PLA, while the highest impact strength of 30.94 kJ/m2 was recorded for neat rPET. The lowest wear of 0.01 g was obtained for the rPET containing 5 wt% marble dust content. The experimental results revealed that for the examined criteria, the order of composite preference is not the same. Therefore, the optimal composite was identified by adopting a preference selection index-based MCDM technique. The findings demonstrated that the 10 wt% marble dust-filled PLA composite appears to be the best solution with favorable physical, mechanical, and wear properties.  相似文献   

8.
The present study investigates the effect of hybrid fillers such as graphene nanoplatelets (GnPs) and Titanium di-oxide (TiO2) in polypropylene (PP) composites on the mechanical properties. The compatibilizing agent of Maleic anhydride grafted polypropylene (MAPP) are used in the polypropylene based composites to increase the interfacial adhesion between matrix and fillers. The experiments are designed according to L16 orthogonal array (OA) based design of experiments (DOE). The parameters selected for this study are GnPs, TiO2 and MAPP with four different levels are used.By using Orthogonal array and Taguchi based experimental design, the performance characteristics of tensile modulus, tensile strength, elongation at break and toughness can be analyzed with more objective through a small set of experiments.Taguchi based analysis are used to find out the optimal parameters to maximize the tensile properties for the GnPs and TiO2 reinforced PP hybrid composites. Further, analysis of variance (ANOVA) is investigated to identify the most significant parameters which influence the mechanical properties.From the analysis it was found that the optimal parameters of 3 ?wt% GnPs, 2 ?wt% TiO2 and 6 ?wt% MAPP for maximum tensile modulus and tensile strength. The most significant parameter for tensile modulus and tensile strength is GnPs followed by TiO2 and MAPP according to ANOVA analysis.  相似文献   

9.
Corn starch (CS) and soy protein isolate (SPI), as inexpensive, abundant, and biodegradable materials, can chemically interact well with each other to produce biofilms. However, to overcome some of their physical and mechanical limitations, it is preferred to use their composite form, employing reinforcing materials. In this study, initially, graphene (G) and graphene oxide (GO) were synthesized by a green method. Then, to enhance the polymer blend final properties, the effects of adding G and GO in the range of 0.5 to 2 wt% on physical and mechanical properties of starch/protein blend were investigated. The results showed that the presence of 0.5‐wt% G and 2‐wt% GO significantly increased the modulus of starch/protein film from 252 to 578 and 449 MPa, respectively. In addition, the thermal stability of CS/SPI/GO (2 wt%) composite film was 50°C to 60°C more than that of the pure starch/protein film. On the other hand, G‐reinforced composite films tended to decline water diffusion compared with the pure polymer film. In addition, the composite film with 2‐wt% GO content had the lowest oxygen permeation rate (3.48 cm3 μm/m2d kpa) among the other composite films.  相似文献   

10.
Mechanical properties of composites made up of ultra‐high‐molecular‐weight polyethylene (UHMWPE) fiber, polyimide (PI), and TiO2 particles were investigated. The hybrid composite of 20 vol% of UHMWPE fiber with TiO2 showed tensile strength greater than UHMWPE fiber/PI composite. A positive hybrid effect in tensile strength is obtained. It is observed that addition of small amount of TiO2 to UHMWPE fiber/PI increased the tensile strength of the composite by 28%. With increase in TiO2 loading to 1 to 3 vol%, the impact strength of the hybrid composite is increased from 55 KJ/m2 to 69 KJ/m2. This maximum value is more than one and a half times greater than the impact strength of neat UHMWPE fiber/PI composite.  相似文献   

11.
《先进技术聚合物》2018,29(5):1487-1496
High‐performance polymer‐based frictional materials have become increasingly important to improve the mechanical output properties of ultrasonic motors. This study discussed the friction and wear behavior of 2 dominating frictional materials of polymer composites for ultrasonic motors, polyimide (PI), and polytetrafluoroethylene (PTFE) filled by aramid fibers (AF) and molybdenum disulfide (MoS2). To explore the wear mechanisms, the tribo‐pair contact stress was theoretically characterized, and the interface temperature rise was numerically predicted. The predictions showed that the flash temperature on asperity tips could reach the glass transition temperature of the polymer materials. The experimental results indicated that the contact stress and sliding speed have a small effect on the friction of the PI composite but influence considerably the friction of the PTFE composite. A higher contact stress brings about a higher specific wear rate, but a higher sliding speed reduces the wear rate. Compared with AF/MoS2/PTFE, the AF/MoS2/PI has much better tribological performance under high loads and speeds.  相似文献   

12.
Thermo‐mechanically durable industrial polymer nanocomposites have great demand as structural components. In this work, highly competent filler design is processed via nano‐modified of micronic SiO2/Al2O3 particulate ceramics and studied its influence on the rheology, glass transition temperature, composite microstructure, thermal conductivity, mechanical strength, micro hardness, and tribology properties. Composites were fabricated with different proportions of nano‐modified micro‐composite fillers in epoxy matrix at as much possible filler loadings. Results revealed that nano‐modified SiO2/Al2O3 micro‐composite fillers enhanced inter‐particle network and offer benefits like homogeneous microstructures and increased thermal conductivity. Epoxy composites attained thermal conductivity of 0.8 W/mK at 46% filler loading. Mechanical strength and bulk hardness were reached to higher values on the incorporation of nano‐modified fillers. Tribology study revealed an increased specific wear rate and decreased friction coefficient in such fillers. The study is significant in a way that the design of nano‐modified mixed‐matrix micro‐composite fillers are effective where a high loading is much easier, which is critical for achieving desired thermal and mechanical properties for any engineering applications. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

13.
The mechanical properties of SiO2 filler particles on carbon fibers have been under discussion for several decades; the diverse models, and the properties of the components relevant to retention, are critically reviewed in the first part of this study. In addition, to gain an insight into some possible combined effect of the carbon fiber/poly(methyl methacrylate) (CF/PMMA), interfacial adhesion strength and the tensile properties and dielectric strength of the hybrid composites were studied. Simple modified rules of mixtures are used to estimate the fiber efficiency factors for the strength and modulus of the hybrid composites. Except, with the increasing fraction of CFs in PMMA, the weld line area's elongation percent is decreased. Whereas for case of SiO2, the 10 wt% is the threshold for micro injection molded weld line tensile strength and dielectric strength turning from decrease trend to increase. Same as CF, elongation of micro weld line samples is in general lower than neat PMMA as well, due to the addition of SiO2 particles.  相似文献   

14.
《先进技术聚合物》2018,29(1):61-68
Bio‐based nanocomposites of poly (butylene adipate‐co‐terephthalate) (PBAT)/silver oxide (Ag2O) were prepared by the composite film casting method using chloroform as the solvent. The prepared Ag2O at different ratios (1, 3, 5, 7, and 10 wt%) is incorporated in the PBAT. The PBAT nanocomposite films were subjected to structural, thermal, mechanical, barrier, and antimicrobial properties. The electron micrographs indicated uniform distribution of Ag2O in the PBAT matrix. However, the images indicated agglomeration of Ag2O particles at 10 wt% loading. The thermal stability of the nanocomposite films increased with Ag2O content. The tensile strength and elongation of the composite films were found to be higher than those of PBAT and increased with Ag2O content up to 7 wt%. The PBAT‐based nanocomposite films showed the lower oxygen and water vapor permeability when compared to the PBAT film. Antimicrobial studies were performed against two food pathogenic bacteria, namely, Klebsiella pneumonia and Staphylococcus aureus.  相似文献   

15.
Mechanical properties and tribological behavior of epoxy resin (EP) and EP nanocomposites containing different shape nanofillers, such as spherical silica (SiO2), layered organo‐modified montmorillonite (oMMT) and oMMT‐SiO2 composites, were investigated. The SiO2‐oMMT composites were prepared by in situ deposition method and coupling agent modification, and transmission electron microscopy (TEM) analysis shows that spherical SiO2 is self‐assembled on the surface of oMMT, which forms a novel layered‐spherical nanostructure. The mechanical properties test results show that oMMT obviously improves the strength of EP and SiO2 enhances its toughness, but oMMT‐SiO2 exhibits a synergistic effect on toughening and reinforcing EP simultaneously. A pin‐on‐disc rig was used to test friction and wear loss of pure EP and EP nanocomposites. The tribological test results prove that these nanofillers with different shapes play different roles for improving the wear resistance of EP nanocomposites. Morphologies of the worn surfaces were studied further by scanning electron microscopy (SEM) observations, and it was clarified that the EP and EP nanocomposites undergo similar wear mechanisms. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

16.
The main goal of this study was to determine the performance of particleboards made from date palm branches (DPB, Phoenix dactylifera), as a low-value raw material and expanded vermiculite (VER), as a natural inorganic filler. DPB is underutilized abundant byproduct in southern parts of Iran. For the purpose of evaluation, compositions of DPB and VER at different mixture rates were compared for some properties. Variable parameters were: number of particleboard layers (single- and three-layer), VER size (micro and nano meter), and VER content (0, 10 and 20 wt%). Other parameters such as resin content (10%), hardener content (2%), pressing time (6 min), board density (0.75 g/cm3), press pressure (35 kg/m2) and press temperature (175 °C) were held constant. Physical properties (thickness swelling (TS), water absorption (WA), and sound absorption coefficient (SAC)), and mechanical properties (modulus of rupture (MOR), modulus of elasticity (MOE), and internal bond strength (IB)) of the boards were determined. Based on the findings of this study, all mechanical properties of the boards slightly decreased when the VER content was increased from 0 to 20 wt%. Analysis of data revealed that the mechanical properties were significantly different among the board types. In general, WA and TS increased with the increase of WER content. The presence of nano VER in the particleboards resulted in higher WA and TS. The SACs of composite boards filled with VER increased as the frequency increased. Nano VER and single-layer boards showed higher SACs in frequency range of 800–1250 Hz. Finally, it can be stated that DPB has potential as replacement fibrous material for particleboard manufacturing and indoor applications.  相似文献   

17.
Linear low density polyethylene (LLDPE) is the one of the most popular polymer used for rotational moulding applications such as storage tanks. But, its inferior mechanical properties and thermal stability restrict the longer service. Hence, this study experimentally demonstrates the effect of Halloysite Nanotube (HNTs) concentration on LLDPE composites for enhancing the mechanical and thermal stability. HNTs were uniformly dispersed with LLDPE matrix through ultra-sonication, followed by compression moulding used to prepare the nano composites plates. The prepared composites are shown 19.2% improved tensile strength for 2 wt% HNTs, whereas 28.9% hike in flexural strength observed for 4 wt% HNTs composite, compare to neat LLDPE. Which shows that higher concentrations of HNTs is favourable in improving the flexural strength rather than tensile properties. In addition to that, higher concentrations of HNTs are also helping in improving the storage modulus of the LLDPE composites. The increase in mechanical properties mainly attributed due to effective load carriers (HNTs) in the composite. Besides, HNTs were also contributing for improving the melting point and residual char of the composites, which is indeed for storage tanks durability. The prepared composite was thermally stable at higher temperature up to 230 °C, because of HNTs chemical structure, the inner layer of HNTs constitute with Al2O3 and outermost layer constitute with SiO2, both are thermally stable. Stated enhancement proves the potential effect of HNTs reinforcement in the LLDPE composite for rotational moulding applications.  相似文献   

18.
Poly(methyl methacrylate) (PMMA), poly(vinyl chloride) (PVC), Nylon 6, and Nylon 6,6 have been electrospun successfully. The nanofibers have been characterized by scanning electron microscopy (SEM), confirming the presence of bead free and fiber‐bead free morphologies. Thermogravimetric analysis (TGA) indicated differences between the thermal stability of PMMA nanofibers and PMMA powder. However, no significant differences were observed between the starting physical form (powder or pellet) of PVC, Nylon 6 and Nylon 6,6, and their corresponding electrospun nanofibers. Differential scanning calorimetry (DSC) demonstrated a lower glass transition temperature (Tg) and water absorption for PMMA electrospun nanofibers. Furthermore, electrospun Nylon 6 and Nylon 6,6 had a slight decrease in crystallinity. Tensile testing was performed on the electrospun nanofibers to obtain the Young modulus, peak stress, strain at break, and energy to break, revealing that the non‐woven mats obtained had modest mechanical properties that need to be enhanced. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

19.
To improve the mechanical and tribological performance, two kinds of wollastonite fillers (fine or coarse) and short carbon fibers (5–15 vol %) were, respectively, incorporated into an epoxy resin. Fine wollastonite fillers remarkably enhanced the flexural modulus, strength, and toughness of the resin at some filler contents (i.e., 10 vol %) simultaneously, while coarse wollastonite fillers and short carbon fibers impaired most of mechanical properties except the modulus. The small particle size, low aspect ratio as well as the good adhesion to the epoxy matrix of the fine wollastonite particles are believed to be responsible for the improved strength and toughness. Tribological tests were performed under sliding and low amplitude oscillating wear conditions. All fillers enhanced the wear resistance and reduced the sliding coefficient of friction but to a different extent. Under sliding wear conditions, fine wollastonite particle‐filled epoxy displayed the highest wear resistance because of the formation of an effective transfer film and the low abrasiveness of the fillers. Under low amplitude oscillating wear conditions, both wollastonite fillers showed much higher wear resistance than short carbon fibers regardless of the filler content. The better adhesion between the wollastonite fillers and the epoxy matrix is responsible for the higher wear resistance under oscillating conditions. The wear tracks were inspected by microscopy to analyze the corresponding wear mechanisms. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 854–863, 2006  相似文献   

20.
A series novel composites based on poly(L‐lactide) (PLLA) oligomer modified mesoporous silica (MCM41) homogeneous dispersed into poly(L‐lactide‐co‐trimethylene carbonate‐co‐glycolide) (PLTG) terpolymer has been successfully prepared. The structure of PLTG terpolymer was characterized by 1H NMR. The structure and properties of modified and unmodified MCM41 were attested by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), X‐ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscope (SEM), and transmission electron microscope (TEM), which demonstrated that the MCM41 was successfully grafted by the PLLA oligomer. The effect of different concentration of modified MCM41 in PLTG matrix on thermal properties, mechanical properties, and hydrophilicity was investigated by TGA, differential scanning calorimetry (DSC), mechanical testing, contact angle measurement, and SEM. The results of mechanical tests showed that 5 wt% of modified MCM41 nanoparticles gave rise to optimal reinforcing effect. The tensile strength, Young's modulus, and elongation at break of the PLTG/PLLA‐MCM41 (5%) composites were 33.2 Mpa, 1.58 Gpa, and 268.7%, respectively, which were all higher than the PLTG/MCM41 (5%) composites and pristine PLTG matrix, which were due to good interfacial adhesion between the PLTG matrix and MCM41 nanoparticles. TGA and DSC have shown that 5% modified MCM41 in the PLTG increased the temperature of composite degradation and Tg. Water contact angle measurement showed the hydrophilicity of the composites increases with the increase of modified MCM41 content. The live/dead assay showed that the modified MCM41 existing on the PLTG matrix presents very excellent cytocompatibility. Therefore, the novel composite material represents promising way for bone tissue engineering application.  相似文献   

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