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1.
The hybrid reinforcement effect of surface‐treated UHMWPE fiber and SiO 2 on the mechanical properties of PMMA matrix composites was investigated. When UHMWPE fiber is introduced, the tensile strength of UHMWPE fiber‐reinforced composites sharply increases. The flexural modulus was enhanced with an increase in filler loading. Flexural modulus of the treated UHMWPE/SiO 2/PMMA composites was higher than that of the UHMWPE/PMMA and UHMWPE/SiO 2/PMMA composites. The outcome of the better interfacial bonding between the filler and the matrix is reflected in the improvement of the mechanical properties of the treated UHMWPE/SiO 2/PMMA composites. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
2.
Mechanical properties of hybrid PMMA composites reinforced with UHMWPE fiber and nano‐titanium dioxide (2, 4, 6, and 8 wt%) was investigated. In this work, the effect of UHMWPE fiber surface treatment on tensile, flexural, and impact properties of PMMA composites was studied. The fiber loadings were varied from 0% to 20%. The addition of UHMWPE fiber had caused a decline in the tensile strength of the PMMA composite. Results revealed that the presence of titanium dioxide on the surface treated UHMWPE fiber has further enhanced the efficiency of stress transfer from the matrix to the fiber thus improved the interfacial adhesion between the UHMWPE fiber and PMMA matrix. 相似文献
3.
Nylon 66 microcomposites with various weight percentage of titanium dioxide (TiO 2) were prepared by a twin screw extruder and investigated for mechanical and tribological properties. Mechanical properties of the composite such as tensile strength/modulus, flexural strength/modulus, impact, and compressive strength first showed an increase up to 6 wt% TiO 2 followed by a decrease at higher filler loading. The value of heat deflection temperature increased with the increase in wt% of TiO 2. Sliding wear tests were performed on pin‐on‐disk equipment under different loads, sliding velocity, and sliding distance combinations. It was found that micro‐TiO 2‐Nylon 66 composite exhibited reduced wear and coefficient of friction up to 6 wt% TiO 2. Micro‐TiO 2 at 2 wt% was most effective in improving the tribological properties of plain nylon 66. The worn surfaces were examined by scanning electron microscopy to understand the wear mechanism. The optimal combination from 2 wt% to 6 wt% micro‐TiO 2‐Nylon 66 can be used depending upon the application requiring improvement in tribological or mechanical properties, respectively. 相似文献
4.
The experimental investigation on combustion behavior and mechanical properties of flame-retardant thermoplastic polyurethane were performed in the article. By the masterbatch-melt blending technique, the TiO2 particles were well dispersed in TPU/APP composites. The microscopic morphology structure was observed by TEM and SEM. TEM images of TPU–TiO2 masterbatch material showed that the grain sizes of TiO2 particles were 200–400 nm. The SEM result indicated that the TiO2 particles could enhance compatibility and dispersion of APP in TPU. The mechanical properties of TPU composites were characterized by dynamic mechanical analysis (DMA) and tensile tests, respectively. The DMA results indicated that TiO2 particles could improve the viscoelastic property of the TPU/APP composites. The tensile strength achieved a significant improvement with addition of TiO2 particles. APP/TiO2-5 obtains a better value of 344% than APP-1 (277%). Also, the flame-retardant property and thermal stability of the TPU composites were characterized using cone calorimeter test (CCT) and thermogravimetric analysis (TGA), respectively. The CCT results revealed that TiO2 particles could enhance the flame-retardant property of APP in TPU. The peak heat release rate of APP/TiO2-4 containing 0.5% TiO2 decreased to 157.27 kW m?2 from 225.5 kW m?2 of APP-1 sample without any TiO2. The TiO2 particles could promote the formation of carbon layers which restrict the diffusion of fuels into combustion zone and access of oxygen to the underlying materials. The TGA results indicated that TiO2 can improve the thermal stability of TPU/APP composites. 相似文献
5.
In this study, helium/oxygen/nitrogen (He/O 2/N 2)‐plasma was used to etch/modify the surface of ultra‐high‐molecular‐weight polyethylene (UHMWPE) fiber. After coated with polyurethane (PU), the plasma treated UHMWPE fabrics were laminated. It was found that the values of peeling strength between the laminated UHMWPE fabrics treated with He/O 2/N 2‐plasma were significantly higher (3–4 times) than that between pristine fabrics. The hydrophilic property and the value of the surface roughness of the UHMWPE fibers increased significantly after treated with He/O 2/N 2‐plasma. The mechanism of the oxidation/degradation of the polymers on the surface of the UHMWPE fiber during He/O 2/N 2‐plasma treatment was suggested. In addition, it was found that the higher content of functional groups (carbonyl, aldehyde, and carboxylic acid) on fiber surface and the higher value of surface roughness of the UHMWPE fiber treated with He/O 2/N 2‐plasma could significantly improve the adhesion‐strength of the laminated UHMWPE fabric. Especially, the micro‐aperture on the surface of UHMWPE fiber caused by the strenuous etching of He/O 2/N 2‐plasma treatment was also an important factor on improving the adhesion‐strength between the laminated UHMWPE fabrics. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
6.
The mechanical behaviour of fluorosilicone rubber–filled PI composites with and without clay was investigated. The clay filled fluorosilicone rubber composite had the highest interlaminar shear strength value of all the combinations because its higher bond strength may have hindered a large fibre/matrix debonding. The maximum tensile strength was observed for 20 vol% fluorosilicone rubber/PI/5vol%clay composite. The interlaminar shear strength of clay filled fluorosilicone rubber/PI composite was greater than that of fluorosilicone rubber/PI composite, which shows that the adhesion factor of the combination of the PI and fluorosilicone rubber was greater. 相似文献
7.
To prevent the loss of fiber strength, ultrahigh‐molecular‐weight polyethylene (UHMWPE) fibers were treated with an ultraviolet radiation technique combined with a corona‐discharge treatment. The physical and chemical changes in the fiber surface were examined with scanning electron microscopy and Fourier transform infrared/attenuated total reflectance. The gel contents of the fibers were measured by a standard device. The mechanical properties of the treated fibers and the interfacial adhesion properties of UHMWPE‐fiber‐reinforced vinyl ester resin composites were investigated with tensile testing. After 20 min or so of ultraviolet radiation based on 6‐kW corona treatment, the T‐peel strength of the treated UHMWPE‐fiber composite was one to two times greater than that of the as‐received UHMWPE‐fiber composite, whereas the tensile strength of the treated UHMWPE fibers was still up to 3.5 GPa. The integrated mechanical properties of the treated UHMWPE fibers were also optimum. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 463–472, 2004 相似文献
8.
Aniline was polymerized in the presence of poly(vinyl chloride) (PVC) powders in hydrochloric acid to in situ prepare poly(vinyl chloride)/polyaniline (PVC/PANI) composite particles. UV‐vis spectra and FT‐IR spectra indicate PANI in PVC/PANI composite particles possessed a higher oxidation state with decreased aniline content in reactants. Both conductivity and impact strength of the dodecylbenzenesulfonic acid (DBSA) doped PANI composites (PVC/PANI‐DBSA), which were compression molded from the in situ prepared PVC/PANI particles, increase with the pressing temperature and decrease with the increase of DBSA doped PANI (PANI‐DBSA) loading. An excellent electric conductivity of 5.06 × 10 ?2 S/cm and impact strength of 0.518 KJ/m 2 could be achieved for the in situ synthesized and subsequently compression molded composite. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
9.
In this study, the self-healing ability of the E-glass fibers/epoxy composites based on microvascular channels under flexural and tensile loading was investigated by a three-part healant. The fabrication of the microvascular channels was conducted through embedding the solid preforms and removing them. The epoxy resin and premix anhydride hardener-CuBr 2 (2-Methylimidazole) as the healing agents were used to study the self-healing ability of the composites at different healing times (4, 7 and 11 days) and various volume fractions for recovering the tensile (2.5, 4 and 8 vol%) and flexural (2, 3.2 and 3.7 vol%) strength. The optimum recovered tensile strength belonged to the composite containing the 4 vol% healant. The obtained healing efficiencies of this composite after 4, 7 and 11 days were 57, 68 and 69%, respectively. In the flexural test, the composite with the 3.2 vol% healant had the maximum healing efficiencies of 3, 46 and 44%, as compared with other composites. By using the field emission scanning electron microscopy and energy dispersed spectroscopy analysis, the healing ability of the composite was confirmed by this healing system. 相似文献
10.
Jute fabrics-reinforced polypropylene (PP) composites (50% fiber) were prepared by compression molding. Composites were fabricated with non-irradiated jute fabrics/non-irradiated PP (C-0), non-irradiated jute fabrics/irradiated PP (C-1), irradiated jute fabrics/non-irradiated PP (C-2) and irradiated jute fabrics/irradiated PP (C-3). It was found that C-3 composite performed the best mechanical properties over other composites. Total radiation dose varied from 250–1000 krad and composites made of using 500 krad showed the best results. The optimized values (C-3 composites) for tensile strength (TS), bending strength (BS) and impact strength (IS) were found to be 63 MPa, 73 MPa and 2.93 kJ/m 2, respectively. 相似文献
11.
Ultra‐high‐molecular‐weight polyethylene (UHMWPE) fibers have been modified by plasma treatment to increase adhesion in high‐density polyethylene (HDPE) matrices. Results showed that surface roughness predominates for modified UHMWPE fibers, indicating that the plasma treatment favors the interaction with HDPE. Unmodified HDPE composite samples gave a lower interlaminar shear strength than did the samples that were incorporated with UHMWPE. The addition of unmodified UHMWPE fibers to the neat HDPE significantly increases interlaminar shear strengths of composites, up to 20 vol%. The oxygen concentration increased from 16.16 %to 21.99%, and the ratio of oxygen to carbon atoms increased significantly from 0.194 to 0.284 after oxygen plasma treatment for 5 minutes with a power of 300 W. 相似文献
12.
A mesoporous iron–titanium mixed-oxides@activated carbon(AC) fiber membrane was fabricated by an electrospinning method and applied to the treatment of phenol waste water. The physical and chemical properties of the composite fiber membrane were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, UV–Vis light diffuse reflectance spectroscopy (DRS), Raman spectroscopy, respectively. The results indicate that the composite nanofiber membrane is composed of α-Fe 2O 3, anatase TiO 2 and activated carbon phases with a specific surface area of 231 m 2 g –1 and narrow pore size distribution of 3–6 nm. DRS reveals that the composite membrane has high photons absorption from both ultraviolet light and visible light irradiation owing to the combination of Fe 2O 3, TiO 2 and carbon. The prepared nano Fe 2O 3–TiO 2@AC fiber membrane can act as an efficient reusable photocatalyst and adsorbent for 100% remo val of phenol pollutant. This hybrid technique is hopeful to be widely used in the treatment of various organic waste waters. 相似文献
13.
TiO 2/PVA composite nanofiber mat was prepared via an electrospinning technology. SH‐TiO 2‐SiO 2 hybrid particles and PVA solution were injected through a coaxial syringe, yielding a composite nanofiber mat. The as‐prepared SH‐TiO 2‐SiO 2/PVA composite nanofiber mat was immersed in Cd 2+ cation solution and S 2? anion solution in turn. Thus, yellow TiO 2@CdS/PVA composite nanofiber mats were prepared. By adjusting the number of times a mat was immersed in the Cd 2+ and S 2? solutions, different amounts of CdS particles attaching to the mats were obtained. Both SH‐TiO 2‐SiO 2/PVA and TiO 2@CdS/PVA composite nanofiber mats were employed to catalyze the photodegradation of a model dye, methylene blue. The photodegradation performance could be greatly enhanced by the introduction of CdS particles anchoring onto TiO 2 particles. The photodegradation efficiency reached 99.2% within 180 min. Also, the nanofiber mat could be recycled and reused at least 10 times. The photodegradation efficiency of TiO 2@CdS/PVA composite nanofiber mats remained 68.8% for 10 cycles. 相似文献
14.
Chemically crosslinked polyimide organic–inorganic composite nanofiltration membranes suitable for application in harsh organic solvents were successfully prepared by phase inversion of dope solutions. TiO 2 nanoparticles were dispersed in these dope solutions, comprising polyimide (PI) in N, N-dimethylformamide/1,4-dioxane. The impact of TiO 2 on the resulting PI membranes was investigated using SEM, TGA, water contact angle, dope viscosity measurements and mechanical strength. The presence of TiO 2 nanoparticles within the membrane matrix was proved by the detection of a peak characteristic of TiO 2 in the WAXS pattern. SEM pictures of the cross-section of the PI/TiO 2 membranes showed dramatically changed morphology compared to reference membranes with no TiO 2 addition. Macrovoids present in reference membranes were suppressed by increasing loading of TiO 2 nanoparticles, and eventually disappeared completely at a TiO 2 loading above 3 wt.%. Decreasing water contact angle and an increase in ethanol flux indicated that hydrophilicity increased as nanoparticle loading increased. The effect of TiO 2 on the functional performance of the membranes was evaluated by measuring flux and rejection using cross-flow filtration. Perhaps surprisingly, the presence of TiO 2 improved the compaction resistance of the membranes, whereas rejection and steady flux were almost unaltered. 相似文献
15.
In this study, a silicic acid and tetra isopropyl ortho titanate ceramic precursor and a metallocene polyethylene‐octene elastomer (POE) or acrylic acid grafted metallocene polyethylene‐octene elastomer (POE‐g‐AA) were used in the preparation of hybrids (POE/SiO 2? TiO 2 and POE‐g‐AA/SiO 2? TiO 2) using an in situ sol‐gel process, with a view to identifying a hybrid with improved thermal and mechanical properties. Hybrids were characterized using Fourier transform infrared spectroscopy, 29Si solid‐state nuclear magnetic resonance (NMR), X‐ray diffraction, differential scanning calorimetry, thermogravimetry analysis, dynamic mechanical thermal analysis, and Instron mechanical testing. Properties of the POE‐g‐AA/SiO 2? TiO 2 hybrid were superior to those of the POE/SiO 2? TiO 2 hybrid. This was because the carboxylic acid groups of acrylic acid acted as coordination sites for the silica‐titania phase to allow the formation of stronger chemical bonds. 29Si solid‐state NMR showed that Si atoms coordinated around SiO 4 units were predominantly Q 3 and Q 4. The 10 wt % SiO 2? TiO 2 hybrids gave the maximum values of tensile strength and glass transition temperature in both POE/SiO 2? TiO 2 and POE‐g‐AA/SiO 2? TiO 2. It is proposed that above this wt %, excess SiO 2? TiO 2 particles caused separation between the organic and inorganic phases. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1690–1701, 2005 相似文献
16.
Herein we report an easy and efficient approach to prepare lightweight porous polyimide (PI)/reduced graphene oxide (RGO) composite films. First, porous poly (amic acid) (PAA)/graphene oxide (GO) composite films were prepared via non‐solvent induced phase separation (NIPS) process. Afterwards PAA was converted into PI through thermal imidization and simultaneously GO dispersed in PAA matrix was in situ thermally reduced to RGO. The GO undergoing the same thermal treatment process as thermal imidization was characterized with thermogravimetric analysis, Raman spectra, X‐ray photoelectron spectroscopy and X‐ray diffraction to demonstrate that GO was in situ reduced during thermal imidization process. The resultant porous PI/RGO composite film (500‐µm thickness), which was prepared from pristine PAA/GO composite with 8 wt% GO, exhibited effective electrical conductivity of 0.015 S m ?1 and excellent specific shielding efficiency value of 693 dB cm 2 g ?1. In addition, the thermal stability of the porous PI/RGO composite films was also dramatically enhanced. Compared with that of porous PI film, the 5% weight loss temperature of the composite film mentioned above was improved from 525°C to 538°C. Moreover, tensile test showed that the composite film mentioned above possessed a tensile strength of 6.97 MPa and Young's modulus of 545 MPa, respectively. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
17.
The degradation of nitro aromatics like trinitrotoluene (TNT) released in the waste water from explosive process plants is
the serious problem due to toxic and explosive nature of TNT. The poor response of TNT to biodegradation enhanced the gravity
of the problem. We have demonstrated that high specific surface area TiO 2–SiO 2 nano-composite aerogel is promising photo catalyst in successful treating of TNT contaminated aqueous solution. The TiO 2–SiO 2 composite aerogel with nominal content of 20 and 50% TiO 2, used as catalyst, were prepared by co-precursor sol–gel method using titanium isopropaxide and tetramethylorthosilicate
as source of titania and silica, respectively. The XRD studies confirmed formation of anatase phase of crystalline TiO 2 with nano sized crystallites. The TiO 2–SiO 2 aerogel showed specific surface area of 1,107 and 485 m 2/g for the aerogels containing 20 and 50% TiO 2, respectively. The 100 ppm TNT solution was treated, in 700 ml capacity reaction vessel, using H 2O 2 oxidizer and TiO 2–SiO 2 aerogel catalyst in presence of UV light (8 W UV lamp). Using TiO 2–SiO 2 (50/50) aerogel with surface area of 485 m 2/g, we succeeded to reduce the TOC to 1 ppm within 3.5 h where as using TiO 2/SiO 2 (20/80) aerogel with surface area of 1,107 m 2/g, the TOC was reduced to about only 7 ppm in the same time. It revealed that the combination of high TiO 2 content and high specific surface area is an important factor to achieve effective and faster degradation of TNT for complete
mineralization. 相似文献
18.
Using rubber to toughen polylactide (PLA) is always accompanied by the sharp reduction in stiffness. Herein, PLA/poly (methyl methacrylate) grafted natural rubber (NR-PMMA) thermoplastic vulcanizates (TPVs) with balanced stiffness-toughness were fabricated. With the addition of 40 wt % NR-PMMA, the impact strength and tensile toughness of PLA/NR-PMMA TPV significantly improved to about 102.7 kJ/m 2 and 66.1 MJ/m 3, respectively, compared with those of 2.7 kJ/m 2 and 2.4 MJ/m 3 for the pure PLA. Meanwhile, the yielding stress was maintained at 34.5 MPa. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of in-situ interfacial compatibilization between PLA and rubber phases. Both tensile and impact toughening mechanism were studied and deduced as considerable energy dissipation provided by the continuous rubber phase. Instrumented notched impact tests demonstrated that the energy dissipating in crack propagation process contributed to the main part of impact toughness. In addition, a novel toughening model based on bicontinuous structure was incorporated, which showed good applicability in predicting the impact strength of PLA/NR-PMMA TPVs. 相似文献
19.
Bi‐ and Y‐codoped TiO 2 photocatalysts were synthesized through a sol‐gel method, and they were applied in the photocatalytic reduction of CO 2 to formic acid under visible light irradiation. The results revealed that, after doping Bi and Y, the surface area of TiO 2 was increased from 5.4 to 93.1 m 2/g when the mole fractions of doping Bi and Y were 1.0% and 0.5%, respectively, and the lattice structures of the photocatalysts changed and the oxygen vacancies on the surface of the photocatalysts formed, which would act as the electron capture centers and slow down the recombination of photo‐induced electron and hole. The photocurrent spectra also proved that the photocatalysts had better electronic transmission capacities. The HCOOH yield in CO 2 photocatalytic reduction was 747.82 μmol/g cat by using 1% Bi‐0.5% Y‐TiO 2 as a photocatalyst. The HCOOH yield was 1.17 times higher than that by using 1% Bi‐TiO 2, and 2.23 times higher than that by using pure TiO 2. Furthermore, the 1% Bi‐0.5% Y‐TiO 2 showed the highest apparent quantum efficiency (AQE) of 4.45%. 相似文献
20.
The polyaniline/TiO 2/graphene oxide (PANI/TiO 2/GO) composite, as a novel supercapacitor material, is synthesized by in situ hydrolyzation of tetrabutyl titanate and polymerization of aniline monomer in the presence of graphene oxide. The morphology, composition and structure of the composites as-obtained are characterized by SEM, TEM, XRD and TGA. The electrochemical property and impedance of the composites are studied by cyclic voltammetry and Nyquist plot, respectively. The results show that the introduction of the GO and TiO 2 enhanced the electrode conductivity and stability, and then improved the supercapacitive behavior of PANI/TiO 2/GO composite. Significantly, the electrochemical measurement results show that the PANI/TiO 2/GO composite has a high specific capacitance (1020 F g −1 at 2 mV s −1, 430 F g −1 at 1 A g −1) and long cycle life (over 1000 times). 相似文献
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