Co-reporter:Hui-Juan Zhang;Fang Guo
Journal of Applied Polymer Science 2012 Volume 124( Issue 1) pp:235-241
Publication Date(Web):
DOI:10.1002/app.33594
Abstract
Modification of composites was a general method to improve their tribological behaviors. On the way to explore composites with enhanced tribological behaviors, we have successfully prepared hybrid PTFE/Nomex fabric/phenolic composite filled with multiwalled carbon nanotubes (MWCNTs) or MWCNTs modified by polystyrene (PS) with a grafting to method. The results of pin-on-disc type wear tests indicated tribological behaviors were improved both for hybrid PTFE/Nomex fabric/phenolic composite filled with MWCNTs and MWCNTs-PS, especially for that of filled with MWCNTs-PS. And the probable reason was also discussed based on the characterization results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Jin Yang, Zhaozhu Zhang, Xuehu Men, Xianghui Xu, Xiaotao Zhu
Journal of Colloid and Interface Science 2010 Volume 346(Issue 1) pp:241-247
Publication Date(Web):1 June 2010
DOI:10.1016/j.jcis.2010.02.040
Poly(acrylic acid)-block-polystyrene (PAA-b-PS) functionalized multiwall carbon nanotubes (MWNTs) were prepared by nitroxide-mediated “living” free-radical polymerization. The product functionalized MWNTs (MWNT-PAA-b-PS) contained 20% by weight PAA-b-PS based on the infrared spectroscopy analysis and thermal gravimetric analysis. Such MWNT-PAA-b-PS nanoparticles can be used in spray coating method to fabricate superhydrophobic MWNT films, and water-droplet mobility on the superhydrophobic film can be reversibly converted from rollable to pinned through adjusting the appearance of PAA chains on the topmost surface of the film. Switching mechanism has been discussed in detail. We also directly observed the air–solid–liquid interface from the above of a water droplet by a microscope to confirm the superhydrophobic states, and proved that the transition between the wettability states appeared on the same surface with reversible conversion of water-droplet mobility.Superhydrophobic poly(acrylic acid)-block-polystyrene functionalized carbon nanotube films were fabricated, and reversible switching of water-droplet mobility from rollable to pinned on the same surface was realized.
Co-reporter:Zhuangzhu Luo, Zhaozhu Zhang, Wenjing Wang, Weimin Liu, Qunji Xue
Materials Chemistry and Physics 2010 Volume 119(1–2) pp:40-47
Publication Date(Web):15 January 2010
DOI:10.1016/j.matchemphys.2009.07.039
A simple and conventional coating-curing process to fabricate superhydrophobic coating surface with both the micro-nano-scale binary structure (MNBS) roughness, and the lowest surface energy hydrophobic groups (−CF3) on engineering materials of stainless steel or other metals was developed by control of curing conditions. Results show that higher temperature and longer cooling time resulted in longer crystallizing process, and the forming PTFE aggregates could slowly produce the crystallization and create the willow-leaf-like or wheat-haulm-leaf-like polymer micro/nano-fiber on the atop surface. The curing temperature dramatically influences the micro/nano-fiber texture of the PTFE/PPS superhydrophobic coating surface, leading to the excellent superhydrophobicity at higher temperature. An increase of the curing temperature is beneficial to fluorine gradient-distribution, PPS thermal-oxidative cross-linking and oxidative reaction, resulting in the enhancement of adhesive strength and mechanical properties of the PTFE/PPS superhydrophobic coatings. A bionic superhydrophobic surface with porous gel-like network and PTFE micro/nano-fiber textures could be created by natural cooling in air, whereas PTFE nano-sphere/-papillates textures could be fabricated by hardening in H2O.
Co-reporter:Xue Hu Men;Zhao Zhu Zhang;Jin Yang;Kun Wang;Wei Jiang
Journal of Applied Polymer Science 2010 Volume 118( Issue 5) pp:2881-2889
Publication Date(Web):
DOI:10.1002/app.32491
Abstract
Three kinds of modified multiwalled carbon nanotubes (MWNTs) with different length were obtained by grafting carboxylic groups on long MWNTs or copolymer groups on short and long MWNTs. The modified MWNTs were examined by infrared spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy (FESEM). Afterward, the modified MWNTs were introduced into poly (furfuryl alcohol) (PFA), and the tribological behaviors of the resultant PFA composite coatings were investigated using a ring-on-block wear tester under dry friction condition. The dispersion of MWNTs in PFA composites and the worn surfaces were investigated by FESEM. The results indicated that the MWNTs dispersion and the tribological behaviors of PFA composite coatings could be obviously improved by modification with the copolymer. More significantly, under similarly uniform dispersion of MWNTs, the tribological properties of PFA composite coatings with short nanotubes presented better results when compared with those with long nanotubes because of the influence of nanotube length on the degree of modification of the MWNTs surfaces. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Fang Guo, Zhaozhu Zhang, Huijuan Zhang, Kun Wang, Wei Jiang
Tribology International 2010 Volume 43(Issue 8) pp:1466-1471
Publication Date(Web):August 2010
DOI:10.1016/j.triboint.2010.02.004
The tribological behavior of the spun Kevlar fabric composites filled with polyfluo wax (PFW) and LaF3 were evaluated using a pin-on-disc friction and wear tester under variable applied load and rotating speed. The worn surface and transfer film of the composites were then examined with SEM. The results indicated that the oxidation of PFW after curing and viscous flow characteristic of PFW in friction process were beneficial to the formation of the compact, uniform and smooth transfer film, corresponding to the excellent wear resistance of the composite filled with 15 wt% PFW. The corresponding wear mechanisms were also discussed.
Co-reporter:Xianghui Xu, Zhaozhu Zhang and Jin Yang
Langmuir 2010 Volume 26(Issue 5) pp:3654-3658
Publication Date(Web):December 11, 2009
DOI:10.1021/la9031128
We have reported an easy means in this paper to imitate the “lotus leaf” by constructing a superhydrophobic surface through a process combining both electroless galvanic deposition and self-assembly of n-octadecanethiol. Superhydrophobicity with a static water contact angle of about 169 ± 2° and a sliding angle of 0 ± 2° was achieved. Both the surface chemical compositions and morphological structures were analyzed. We have obtained a feather-like surface structure, and the thickness of the Ag film is about 10−30 μm. The stability of the superhydrophobic surface was tested under the following three conditions: (1) pH value from 1 to 13; (2) after freezing treatment at −20 °C; (3) at ambient temperature. It shows a notable stability in that the contact angle of the sample still remained higher than 150° in different conditions. It can be concluded that our approach can provide an alternative way to fabricate stable superhydrophobic materials.
Co-reporter:Xianghui Xu, ZhaoZhu Zhang, Jin Yang
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2010 Volume 355(1–3) pp:163-166
Publication Date(Web):20 February 2010
DOI:10.1016/j.colsurfa.2009.12.012
A superhydrophobic poly(methyl methacrylate) (PMMA)/silver thiolate composite has been fabricated by a simple spraying method. Compared with the intrinsically hydrophilic pure PMMA, the as-prepared PMMA composite coating displayed a superhydrophobic property. And the UV–vis spectra displayed a notable absorption of light in the ultraviolet range (UVA light), which made the composite potential material for ultraviolet absorption applications.
Co-reporter:Jin Yang, Zhaozhu Zhang, Xuehu Men, Xianghui Xu
Applied Surface Science 2009 Volume 255(Issue 22) pp:9244-9247
Publication Date(Web):30 August 2009
DOI:10.1016/j.apsusc.2009.07.010
Abstract
Stable, transparent and superhydrophobic carbon nanotube (CNT) nanocomposite films were fabricated by one-step spray casting process using the polystyrene functionalized CNTs, which were prepared by “living” free-radical polymerization and analyzed by means of infrared spectroscopy and thermal gravimetric analysis. The CNT film has a high water contact angle of 160° and a sliding angle of less than 3°. The surface topography of the fabricated film was characterized by field emission scanning electron microscopy. The transparency of the CNT film was investigated by UV–vis spectroscopy. The result shows that the CNT film has light transmittance of about 78% in the visible light region.
Co-reporter:Hui-juan Zhang, Zhao-zhu Zhang, Fang Guo, Kun Wang, Wei Jiang
Materials Chemistry and Physics 2009 Volume 116(Issue 1) pp:183-190
Publication Date(Web):15 July 2009
DOI:10.1016/j.matchemphys.2009.03.008
Multi-walled carbon nanotubes (MWCNTs) are important nano-fillers in polymer composites. In this paper, enhanced wear properties of nanocomposites were achieved through introducing functionalized multi-walled carbon nanotubes into hybrid PTFE/cotton fabric composite. Results of characterizations, including Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM), revealed that MWCNTs were successfully functionalized and the modification led to an improvement in the dispersion of MWCNTs. The reasons for the enhanced tribological properties of hybrid PTFE/cotton fabric composite were also discussed based on the results of characterizations.
Co-reporter:Fang Guo;Zhaozhu Zhang;Huijuan Zhang;Weimin Liu
Journal of Applied Polymer Science 2009 Volume 111( Issue 5) pp:2419-2425
Publication Date(Web):
DOI:10.1002/app.29239
Abstract
The friction and wear characteristics of ZnO- or montmorillonite-nanoparticle-filled Kevlar fabric composites with different filler proportions when sliding against stainless steel pins under dry friction conditions were studied, with unfilled Kevlar fabric composites used as references. The worn surface and transfer film of Kevlar fabric composites were then examined with a scanning electron microscope. It was found that ZnO and montmorillonite as fillers could improve the tribological behavior of the Kevlar fabric composites with various applied loads, and the best antiwear property was obtained with the composites containing 5 wt % ZnO or montmorillonite. This indicated that these nanoparticles could prevent the destruction of Kevlar fabric composites during the friction process. The transfer film established by these nanoparticles during the sliding wear of the composites against their metallic counterpart made contributions to reducing the friction coefficient and wear rate of the Kevlar fabric composites measured in the test. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Hui-Juan Zhang;Fang Guo
Journal of Applied Polymer Science 2009 Volume 114( Issue 6) pp:3980-3986
Publication Date(Web):
DOI:10.1002/app.30994
Abstract
Hybrid PTFE/Kevlar fabric was surface-modified by air plasma to improve the adhesion to phenolic resin. The tribological properties of fabric composite with or without plasma-treated hybrid PTFE/Kevlar fabric were investigated in detail. Friction and wear tests showed that friction-reducing and antiwear ability of hybrid PTFE/Kevlar fabric composite were remarkably improved after plasma treatment. Scanning electron microscopy and X-ray photoelectron spectroscopy results indicated that the fiber surfaces were etched and the contents of oxygen and nitrogen increased after plasma treatment, which was favorable for improved fiber/resin bonding strength. The enhancement contributed to the improved tribological properties of hybrid PTFE/Kevlar fabric composite after plasma treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Co-reporter:Hui-juan Zhang, Zhao-zhu Zhang, Fang Guo, Wei Jiang, Wei-min Liu
Tribology International 2009 Volume 42(Issue 7) pp:1061-1066
Publication Date(Web):July 2009
DOI:10.1016/j.triboint.2009.03.002
Co-reporter:Fang Guo, Zhao-Zhu Zhang, Wei-Min Liu, Feng-Hua Su, Hui-Juan Zhang
Tribology International 2009 Volume 42(Issue 2) pp:243-249
Publication Date(Web):February 2009
DOI:10.1016/j.triboint.2008.06.004
Pure and plasma-treated Kevlar fabrics were used to prepare Kevlar fabric/phenolic composites by consecutive dipping of the fabric in phenolic adhesive resin. The friction and wear performance of the resulting composites has been evaluated in a pin-on-disk wear tester at various dry-sliding conditions. The surface changes occurring on Kevlar fibers treated with air–plasma were analyzed by using X-ray photoelectron spectroscope (XPS), Fourier transform infrared spectroscope (FT-IR) and scanning electron microscope (SEM). Moreover, the impact of air–plasma treatment time and power on the friction and wear behavior of Kevlar fabric/phenolic composites composed of the air–plasma-treated Kevlar fabrics was systematically studied. It was found that plasma treatment can significantly improve the tribological performance of the prepared Kevlar fabric/phenolic composites; the best performance was after a plasma treatment at 50 W for 15 min. The plasma treatment generates oxygenic and nitrogenous groups on the surface of the fabric, coupled with an increase of the surface roughness, strengthening the bond between the Kevlar fabric and phenolic adhesive resin and hence improving the tribological properties of the Kevlar fabric/phenolic composites.
Co-reporter:Hui-Juan Zhang;Fang Guo;Wei-Min Liu
Polymer Engineering & Science 2009 Volume 49( Issue 1) pp:115-122
Publication Date(Web):
DOI:10.1002/pen.21228
Abstract
A chemical grafting method was applied to modify TiO2 nanoparticles through covalently introducing glycidoxypropyltrimethoxy silicane (KH560) followed by polyoxymethylene onto the particles to overcome the disadvantages generated by the agglomeration of nanoparticles. TiO2 nanoparticles unmodified and modified were introduced into hybrid polytetrafluoroethylene (PTFE)/cotton fabric composites. Friction and wear test demonstrated that TiO2 nanoparticles unmodified and modified can significantly increase the wear resistance of hybrid PTFE/cotton fabric composites but cannot reduce the friction coefficient. Fabric composites filled with grafted TiO2 nanoparticles exhibited a lower wear rate due to the disintegration of agglomeration and the improvement of interfacial adhesion between filler/matrix. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers
Co-reporter:Zhuangzhu Luo, Zhaozhu Zhang, Wenjing Wang, Weimin Liu
Surface and Coatings Technology 2009 203(10–11) pp: 1516-1522
Publication Date(Web):
DOI:10.1016/j.surfcoat.2008.11.032
Co-reporter:XiangHui Xu, ZhaoZhu Zhang, Weimin Liu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2009 Volume 341(1–3) pp:21-26
Publication Date(Web):5 June 2009
DOI:10.1016/j.colsurfa.2009.03.028
A superhydrophobic perfluorooctanoic acid modified TiO2/polystyrene nanocomposites coating was fabricated by a facile spraying process. As modified by perfluorooctanoic acid, the TiO2/polystyrene nanocomposites changed from hydrophilic (86°) to hydrophobic (166°). The wettability can be adjusted by controlling the drying temperature and the content of modified TiO2 nanoparticles. When the weight ratio of perfluorooctanoic acid modified TiO2 to polystyrene was 1:1, the maximum of contact angle was obtained at 180 °C. As the content of perfluorooctanoic acid modified TiO2 increased, the maximum of contact angle was achieved at 100 °C.
Co-reporter:Fang Guo, Zhao-Zhu Zhang, Hui-juan Zhang, Wei-min Liu
Composites Part A: Applied Science and Manufacturing 2009 Volume 40(Issue 8) pp:1305-1310
Publication Date(Web):August 2009
DOI:10.1016/j.compositesa.2009.06.001
Friction and wear behavior of one-step or two-step air plasma treated and untreated PBO fabric composites has been evaluated in a pin-on-disc friction and wear tester. Tensile property of impregnated fabric and bond property between fabric and metallic substrate have also been studied. A comparison has been made between untreated and plasma treated fibers by using XPS, FTIR, FESEM and SEM. The results indicated that, air plasma treatment could increase the friction coefficient but decrease the wear rate of the PBO fabric composites. The most suitable condition of plasma treatment was 50 W and 15 min. After two-step plasma treatment, the tensile strength of the PBO fabric was decreased by 40%. While the antiwear property and bonding strength of the PBO fabric composites could be improved by 40–67% and 64%, respectively, which was due to the improvement of the bond property among the fiber, the adhesive and substrate.
Co-reporter:Z. Z. Luo;Z. Z. Zhang;L. T. Hu;W. M. Liu;Z. G. Guo;H. J. Zhang ;W. J. Wang
Advanced Materials 2008 Volume 20( Issue 5) pp:970-974
Publication Date(Web):
DOI:10.1002/adma.200701229
Co-reporter:Xue-Hu Men, Zhao-Zhu Zhang, Hao-Jie Song, Kun Wang, Wei Jiang
Applied Surface Science 2008 Volume 254(Issue 9) pp:2563-2568
Publication Date(Web):28 February 2008
DOI:10.1016/j.apsusc.2007.08.084
Abstract
Superhydrophobic films of poly(furfuryl alcohol)/multi-walled carbon nanotubes (PFA/MWNTs) composites have been obtained by using fluorocarbon-modified MWNTs (MWNT-OOCC7F15), PFA, and PTFE with a simple preparation method. The prepared films showed both high contact angle and small sliding angle for water droplets. The chemical compositions and microstructures of the resultant film surfaces were also investigated by means of infrared spectroscopy, X-ray photoelectron spectroscopy, and field emission scanning electron microscope, respectively. Both the formed multiscale roughness structures and the lower surface energy play an important role in creating the superhydrophobic surfaces of PFA/MWNTs composites.
Co-reporter:Fang Guo;Wei-min Liu;Feng-hua Su;Hui-juan Zhang
Journal of Applied Polymer Science 2008 Volume 110( Issue 3) pp:1771-1777
Publication Date(Web):
DOI:10.1002/app.28124
Abstract
The friction and wear behavior of Kevlar fabric composites reinforced by PTFE or graphite powders was investigated using a Xuanwu-III friction and wear tester at dry sliding condition, with the unfilled Kevlar fabric composite as a reference. The worn surfaces were analyzed by means of scanning electron microscope, and X-ray photoelectron spectroscopy. It was found that PTFE or graphite as fillers could significantly improve the tribological behavior of the Kevlar fabric composites, and the Kevlar fabric composites filled with 20% PTFE exhibited the best antiwear and antifriction ability among all evaluated cases. The transfer films established with two lubricants in sliding wear of composites against metallic counterparts made contributions to reducing friction coefficient and wear rate of Kevlar fabric composites. In particular, FeF2 generated in the sliding of Kevlar fabric composites filled with PTFE against counterpart pin improved the bonding strength between the transfer film and counterpart surface, which accounted for the lowest friction coefficient and wear rate of the Kevlar fabric composites filled with PTFE measured in the testing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
Co-reporter:Hao-Jie Song, Zhao-Zhu Zhang
Tribology International 2008 Volume 41(Issue 5) pp:396-403
Publication Date(Web):May 2008
DOI:10.1016/j.triboint.2007.09.004
In order to overcome the disadvantages generated by the loosened nanoparticle agglomerates dispersed in polymer composite coatings, nano-TiO2 particles are modified using trifluoracetic acid. The friction and wear properties of the phenolic coatings filled with different surface treated nano-TiO2, sliding against AISI-C-52100 steel ring under dry sliding, were investigated on a MHK-500 wear tester. Owing to the effective improvement of their dispersibility in the phenolic coating, compared with the cases of untreated nano-TiO2, the employment of modified nano-TiO2 provided the phenolic coating with much better tribological performance. Worn surfaces of the untreated nano-TiO2 or modified nano-TiO2 filled phenolic coating and transfer films formed on the surface of the counterpart ring sliding against the composite coating were respectively investigated by SEM and optical microscope (OM), from which it is assumed that the optimal content of TiO2 or TF-TiO2 is able to enhance the adhesion of the transfer films to the surface of counterpart ring. As a result, the wear resistance of the phenolic composite coating filled with modified nano-TiO2 was significantly enhanced, especially at extreme wear conditions, i.e. high contact pressures.
Co-reporter:Hao-Jie Song, Zhao-Zhu Zhang, Xue-Hu Men
Composites Part A: Applied Science and Manufacturing 2008 Volume 39(Issue 2) pp:188-194
Publication Date(Web):February 2008
DOI:10.1016/j.compositesa.2007.11.003
The tribological behaviors of polyurethane (PU) composite coatings filled with nano-SiO2 were investigated using a ring-on-block wear tester under different friction conditions, and the worn surfaces of nano-SiO2 filled PU coating and transfer films formed on the surface of the counterpart ring were investigated by scanning electron microscopy (SEM) and optical microscope (OM), respectively. The results show that the tribological behaviors of SiO2 filled PU coating are very sensitive to the formation of transferred films. The wear life of the SiO2 filled PU coating under water lubrication is the lowest and under liquid paraffin lubrication is the highest. The OM analyses indicated that a lubricating film can be more easily formed on the frictional surfaces under liquid paraffin lubrication; thus the lubrication condition at the rubbing surfaces can be greatly improved, leading to the decrease of the friction and wear of nano-SiO2 filled PU coating. However, water hinders the formation of transferred films and might penetrate and corrode the filler–matrix interface, which lead to the worst anti-wear property of nano-SiO2 filled PU coating.
Co-reporter:Hao-Jie Song, Zhao-Zhu Zhang, Xue-Hu Men
European Polymer Journal 2007 Volume 43(Issue 10) pp:4092-4102
Publication Date(Web):October 2007
DOI:10.1016/j.eurpolymj.2007.07.003
The toluene-2,4-diisocyanate (TDI) treatment was used to bind isocyanate functional groups (OCN–) on the surface of multi-walled carbon nanotubes (MWCNTs), after which the TDI modified MWCNTs and unmodified MWCNTs were added to the polyurethane (PU) to produce composite coatings with improved wear properties. When the modified MWCNTs were added to the PU binder, the grafting TDI can take part in the curing of the PU binder so that chemical bonding was established between the MWCNTs and the matrix. Friction and wear tests indicated that modified MWCNT reinforced PU composite coating has the highest coefficient of friction and the highest wear resistance of the examined composite coating. Furthermore, the effects of sliding speed and applied load on the friction and wear behavior of the PU coating filled with MWCNTs or MWCNTs-TDI were also studied. The results showed that the coefficient of friction decreased with increasing sliding speed and applied load, and the anti-wear behavior of the PU coating filled with MWCNTs-TDI was the best under 320 N at a speed of 3.0 m s−1.
