Durability Testing of Composite Aerospace Materials Based on a New Polymer Carbon Fiber-Reinforced Epoxy Resin

In this study,the durability of a new polymer carbonfiber-reinforced epoxy resin used to produce composite material in the aerospacefield is investigated through analysis of the corrosion phenomena occurring at the microscopic scale,and the related infrared spectra and thermal properties.It is found that light and heat can con-tribute to the aging process.In particular,the longitudinal tensile strength displays a non-monotonic trend,i.e.,itfirst increases and then decreases over time.By contrast,the longitudinal compressive and inter-laminar shear strengths do not show significant changes.It is also shown that the inter-laminar shear strength of carbonfiber/epoxy resin composites with inter-laminar hybrid structure is better than that of pure carbonfiber materials.The related resistance to corrosion can be improved by more than 41%.

Enhanced corrosion resistance of epoxy resin coating via addition of CeO_(2) and benzotriazole

The use of fillers to enhance the corrosion protection of epoxy resins has been widely applied.In this work,cerium dioxide(CeO_(2))and benzotriazole(BTA)were introduced into an epoxy resin to enhance the corrosion resistance of Q235 carbon steel.Scanning electron microscopy results indicated that the CeO_(2) grains were rod-like and ellipsoidal in shape,and the distribution pattern of BTA was analyzed by energy dispersive spectroscope.The dynamic potential polarization curve proved the excellent corrosion resistance of the composite epoxy resin with CeO_(2) and BTA co-addition,and electrochemical impedance spectroscopy test analysis indicated the significantly enhanced long-term corrosion protection performance of the composite coating.And the optimal protective performance was provided by the coating containing 0.3%(mass)CeO_(2) and 20%(mass)BTA,which was attributed to the barrier performance of CeO_(2) particles and the chemical barrier effect of BTA.The formation of corrosion products was analyzed using X-ray diffraction.In addition,the corrosion resistance mechanism of the coating was also discussed in detail.

Influence of Non-smooth Surface on Tribological Properties of Glass Fiber-epoxy Resin Composite Sliding against Stainless Steel under Natural Seawater Lubrication

With the development of bionics, the bionic non-smooth surfaces are introduced to the field of tribology. Although non-smooth surface has been studied widely, the studies of non-smooth surface under the natural seawater lubrication are still very fewer, especially experimental research. The influences of smooth and non-smooth surface on the frictional properties of the glass fiber-epoxy resin composite（GF/EPR） coupled with stainless steel 316 L are investigated under natural seawater lubrication in this paper. The tested non-smooth surfaces include the surfaces with semi-spherical pits, the conical pits, the cone-cylinder combined pits, the cylindrical pits and through holes. The friction and wear tests are performed using a ring-on-disc test rig under 60 N load and 1000 r/min rotational speed. The tests results show that GF/EPR with bionic non-smooth surface has quite lower friction coefficient and better wear resistance than GF/EPR with smooth surface without pits. The average friction coefficient of GF/EPR with semi-spherical pits is 0.088, which shows the largest reduction is approximately 63.18% of GF/EPR with smooth surface. In addition, the wear debris on the worn surfaces of GF/EPR are observed by a confocal scanning laser microscope. It is shown that the primary wear mechanism is the abrasive wear. The research results provide some design parameters for non-smooth surface, and the experiment results can serve as a beneficial supplement to non-smooth surface study.

Resorcinol-formaldehyde resin-based porous carbon spheres with high CO_2 capture capacities

Porous carbon spheres are prepared by direct carbonization of potassium salt of resorcinol-formaldehyde resin spheres, and are investigated as COadsorbents. It is found that the prepared carbon materials still maintain the typical spherical shapes after the activation, and have highly developed ultra-microporosity with uniform pore size, indicating that almost the activation takes place in the interior of the polymer spheres. The narrow-distributed ultra-micropores are attributed to the "in-situ homogeneous activation"effect produced by the mono-dispersed potassium ions as a form of -OK groups in the bulk of polymer spheres. The CS-1 sample prepared under a KOH/resins weight ratio of 1 shows a very high COcapture capacity of 4.83 mmol/g and good CO/Nselectivity of7-45. We believe that the presence of a welldeveloped ultra-microporosity is responsible for excellent COsorption performance at room temperature and ambient pressure.

Experimental Study on Influence of Dimples on Lubrication Performance of Glass Fiber-epoxy Resin Composite under Natural Seawater Lubrication

Bionic non-smooth surface is widely applied in metal and ceramics materials. In order to introduce this technology to high pressure seawater pump, the influence of bionic non-smooth surface on the engineering plastics used in pump should be investigated. The comparative tests are carried out with a ring-on-disc configuration under 800, 1000, 1200 and 1400 r/min in order to research the influence of the bionic non-smooth surface on glass fiber-epoxy resin composite（GF/EPR） under natural seawater lubrication. The disc surfaces are textured with five kinds of pits, which are semi-spherical, conical, cone-cylinder combined, cylindrical pits and through holes, respectively. A smooth surface is tested as reference. The results show that the lubrication performance of dimpled GF/EPR sample is much better than that of the smooth sample under all rotational speeds. The semi-spherical pits surface has more obvious friction reduction than the others, which shows that the least reduction is approximately 43.29% of smooth surface under 1200 r/rain. However, the wear level is only marginally influenced by dimples. The surface morphology investigations disclose severe modifications caused by abrasive wear primarily. The results are helpful to vary friction properties of GF/EPR by non-smooth surface, or provide references to the design of non-smooth surfaces under certain condition.

Determination of Water Diffusion Coefficients and Dynamics in Adhesive/Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis（EDX） is used to establish the content change of oxy- gen in the adhesive in adhesive/carbon fther reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analy-sis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of beth energy dispersive X-ray spectroscopy and elemental analysis. The de- termined results with EDX analysis are almost the same as those determined with elemental analysis and the results al- so show that the durability of the adhesive/carbon fther reinforced epoxy resin composite joints subjected to silane cou- pling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treat- ment.

Preparation of Low Cost Activated Carbon from Deactivated Resin Catalyst for Methyl Tert-Butyl Ether Synthesis and Its Application in Dimethyl Sulfide Adsorption with Transition Metal Impregnation

In this paper, a low-cost activated carbon(AC) was prepared from deactivated resin catalyst(DRC) for methyl tert-butyl ether(MTBE) synthesis through carbonization and subsequent steam activation treatment. The activated carbon was characterized in detail. After loading various transition metals, including Cu^(2+), Ag+, Co^(2+), Ni^(2+), Zn^(2+), and Fe^(3+) via the ultrasonic-assisted impregnation method, a series of metal-loaded adsorbents(xM-AC) were obtained and their dimethyl sulfide(DMS) adsorption performance was investigated in a batch system. Among these adsorbents, 15Cu-AC presented a superior DMS adsorption capacity equating to 58.986 mg/g due to the formation of S-M(σ) bonds between Cu^(2+) and sulfur atoms of DMS as confirmed by the Raman spectra and kinetic study.

Comparison between Decolorization Effects of Activated Carbon and Macroporous Resin on Periplaneta americana L. Skimmed Cream

[Objective] The aim of this study was to investigate the decolorization ef- fects of activated carbon and macroporous resin on Periplaneta americana L. skimmed cream and compare the advantages and disadvantages of the two decolorization technologies. [Method] Periplaneta americana L. skimmed cream was decolored with activated carbon and macroporous resin, and freeze-dried to collect solid decolorization products. By investigating the yield, decolorization rate, protein retention rate and decolorization operation process, the advantages and disadvantages of the two decolorization technologies were compared. [Result] Both activated carbon and macroporous resin can be used for decolorization. To be specific, macroporous resin-decolorization is superior in the yield and protein retention rate, while activated carbon-decolorization is superior in decolorization rate and decolorization operation process. [Conclusion] Macroporous resin-decolorization can be used if protein is the main ingredient required in the experiment, while activated carbon-decolorization can be used if protein is not the main ingredient required.

An Efficient and Novel Synthesis of Carbamate Esters from the Coupling of Amines, Halides and Carbon Dioxide in the Presence of Basic Resin

A convenient, efficient, one-pot, novel process has been developed for the synthesis of carbamates from corresponding alkyl halides and amines using basic resin/CO2 system.

Optimizing pyrolysis of resin carbon for anode of lithium ion batteries

Pyrolytic resin carbon anode for lithoum ion batteries was prepared from thermosetting phenolic resin. Pyrolysis of the primary phenolic resin and the dewatered one was studied by thermal gravimetric analysis. Structures and characteristics of the carbon materials were determined by X-ray diffraction, Brunauer-Emmer-Teller surface area analysis and electrochemical measurements. With the increase of pyrolyzing temperature and soaking time, the resin carbon material has larger crystallite sizes of L_c and L_a, lower specific surface area, smaller irreversible capacity and higher initial coulombic efficiency. The pyrolyzing temperature and soaking time are optimized to be 1050℃ and 2h. The resin carbon anode obtained under the optimum conditions shows good electrochemical performances with reversible capacity of 387mA·h/g and initial coulombic efficiency of 69.1%.

Synergistic regulation of current-carrying wear performance of resin matrix carbon brush composites with tungsten copper composite powder

Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flake graphite powders that were evenly loaded with tungsten copper composite powder(RMCBCs-W@Cu)exhibited a low wear rate of 1.63 mm^(3)/h,exhibiting 48.6%reduction in the wear rate relative to RCMBCs without additives(RMCBCs-0).In addition,RMCBCs-W@Cu achieved a low friction coefficient of 0.243 and low electric spark grade.These findings indicate that tungsten copper composite powders provide particle reinforcement and generate a gradation effect for the epoxy resin(i.e.,connecting phase)in RMCBCs,which weakens the wear of RMCBCs caused by fatigue under a cyclic current-carrying wear.

Kinetic Study of Resin-Curing on Carbon Fiber/Epoxy Resin Composites by Microwave Irradiation

Microwave processing has great potential for improving composite manufacturing such as reduction of curing time, energy requirements and operational costs. In this paper, the effects of microwave irradiation for resin-curing of carbon fiber/epoxy resin composite that was composed of discontinuous carbon fibers of 130 μm or 3 mm were investigated. The mechanical properties of carbon fiber/epoxy resin composite cured by microwave irradiation for 20 min at 120°C were similar to ones of the sample prepared by conventional oven for 180 min at 120°C. Microwavecured carbon fiber/epoxy resin composite had higher glass transition temperature than the one prepared by conventional oven. The relation between curing time and flexural modulus indicated that the curing velocity of microwave-irradiated carbon fiber/epoxy resin composite was 9 times faster than the one prepared by conventional oven. Furthermore, activation energies for resincuring reaction on microwave and conventional-cured carbon fiber/epoxy resin composite were estimated. The resin-curing reaction in carbon fiber/epoxy resin composite was promoted by microwave irradiation.

Enhanced Thermal Conductivity of Carbon Nanotube Arrays by Carbonizing Impregnated Phenolic Resins

A carbonization method is reported to improve the thermal conductivity of carbon nanotube (CNT) arrays. After being impregnated with phenolic resins, CNT arrays were carbonized at a temperature up to 1400°C. As a result, pyrolytic carbon was formed and connected non-neighboring CNTs. The pyrolysis improved the room temperature conductivity from below 2 W/m·K up to 11.8 and 14.6 W/m·K with carbonization at 800°C and 1400°C, respectively. Besides the light mass density of 1.1 g/cm3, the C/C composites demonstrated high thermal stability and a higher conductivity up to 21.4 W/m·K when working at 500°C.

Preparation of carbon brushes with thermosetting resin binder

Carbon brushes with a resin binder were prepared according to an industrial process and the effects of the molding pressure, grains size and cure temperature on the properties of brush samples were discussed. The results show that the bulk density, bending strength and Rockwell hardness increase, while resistivity decreases with increasing molding pressure. Cure temperature has much more influence on the properties of brushes than molding pressure and grains size. Isothermal differential scanning calorimetry(DSC) was used to estimate the degree of cure of resin binder and a novel method of using the true density to measure the degree of cure of resin binder was presented and discussed briefly. Based on optimal process parameters carbon brushes were manufactured, durability tests for brushes were carried out on an alternate current motor and scanning electron microscope(SEM) was adopted to observe the morphology of worn surface of brushes. The results show that a luster oxide film can be formed on the surface of brushes and their service life reaches 380 h.

Elements, Structure and Electrochemical Property of Carbon Derived from La^(3+) Adulterating Polystyrene Cation Exchange Resin

The polystyrene cation exchange resin was exchanged by La 3+ and then were carbonized to make resin carbon material. The electrochemical properties of the resin carbon material as the electrode of the lithium ion cell were investigated. The test results show that comparing with the polystyrene cation exchange resin without adulterating, the contents of hydrogen, oxygen and sulfur are changed obviously for the resin carbon material derived from the La 3+ adulterating polystyrene cation exchange resin. The contents of hydrogen and oxygen are increased, and the one of sulfur is decreased. The test results also indicate that it is more easily to form the stratum graphite minicrystal structure with bigger diameter for the La 3+ adulterating resin. According to the electrochemical test results, the electrode derived from La 3+ adulterating polystyrene cation exchange resin has much better electrochemical property, and the capacity of charge and discharge of the electrode is increased about 30 mAh·g -1 in average.

Carbonization of Ni-doped Phenol Resin Under Various Conditions

Ni-doped phenol resin was prepared with 1∶100 mass ratio of Ni（ NO_3）_2·6H_2O to thermosetting phenol resin to optimize the structure and properties of pyrolytic carbon derived from phenol resin and increase its carbon yield. The specimens were cured at 200 ℃ and carbonized under different atmospheres（ carbon-embedded atmosphere and Ar atmosphere） and at different temperatures（ 600,800,1000 and 1200 ℃） for3 h,respectively. The carbon yield was measured. Thermal decomposition characteristics of Ni-doped phenol resin,and the oxidation resistance,phase composition and microstructure of pyrolytic carbon were characterized by differential scanning calorimetry,X-ray diffraction,energy dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. The results show that the carbon yield of Ni-doped phenol resin carbonized at800 or 1 000 ℃ is increased significantly,compared with that without any dopants. The graphitization degree of pyrolytic carbon structure derived from Ni-doped phenol resin increases with the increase of carbonization temperature. The massive multi-wall carbon nanotubes of 50-100 nm in diameter and of micrometre scale in length are generated at 1000 ℃. Compared with the carbonembedded atmosphere,carbon nanotubes can be more easily generated in Ar atmosphere,resulting in higher carbon yield and degree of crystallinity of the pyrolyticcarbon derived from Ni-doped phenol resin. The oxidation resistance of the pyrolytic carbon derived from Ni-doped phenol resin at 1200 ℃ is improved significantly and its highest oxidation temperature is increased by about 84℃,compared with that from Ni free phenol resin.

Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

Research of Lignin Modified Phenol Formaldehyde Resin Bonded Magnesia Carbon Bricks

In order to reduce the cost and to improve the low temperature bonding strength of phenol formaldehyde resin（ PF）,the lignin modified phenol formaldehyde resin（ LPF） was synthesized using calcium lignosulfonate as a partial replacement of phenol,and sodium hydroxide as catalyzer. Then the magnesia carbon bricks were prepared using the LPF as binder. Different process conditions of LPFs such as calcium lignosulfonate additions（ 10%,20%,30%,40% and 50%,in mass,the same hereinafter）,catalyzer additions（ extra added,1%,2%,3%,4% and 5%） and reaction times（ 1,1. 5,2,2. 5 and 3 h） were investigated. Effects of prepared LPFs on properties of magnesia carbon bricks（ baked at 200 ℃ for 24 h） were researched in order to modify the synthesizing conditions of LPFs. Cold physical properties and hot modulus of rupture of magnesia carbon bricks bonded by LPF and by traditional PF after baked at 200 ℃ for 24 h and fired at 1 200 ℃ for 3 h were compared,respectively. The results show that the optimal synthesizing conditions of LPF for preparing magnesia carbon bricks are 30% calcium lignosulfonate,1% catalyzer,and 2 h reaction time. The magnesia carbon bricks bonded by the optimal LPF achieve：（ 1） the bulk densities 2. 84 g · cm- 3and 2. 82g·cm- 3,apparent porosities 9. 6% and 14. 6%,moduli of rupture 17. 8 MPa and 6. 4 MPa,crushing strengths72. 3 MPa and 48. 7 MPa,after baked at 200 ℃ and1 200 ℃,respectively;（ 2） the hot modulus of rupture7. 3 MPa after fired at 1 400 ℃. The above properties are better than those of the magnesia carbon brick bonded by PF.

Pyrolysis of furfural-acetone resin as matrix precursor for new carbon materials

In order to increase the understanding of the pyrolysis mechanism, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetry-mass spectrometric coupling technique (TG-MS) were used to study the pyrolysis behavior of furfural-acetone resin used for new carbon materials. The curing and carbonization mechanisms of furfural-acetone resin were mainly investigated; structural changes and volatile products evolved during pyrolysis were analyzed. The results indicate that, during pyrolysis of furfural-acetone resin adding 7% (mass fraction) phosphorous acid as curing agent, the rupture of C—O bond in the five-membered heterocycle firstly takes place to release oxygen atoms and then does the C—H bond, which enable the molecular chain to cross-link and condense, then lead to the formation of three dimensional networking structure. With the increase of pyrolyzing temperature, the scission of methyl and the opening of furan ring are generated. As a result, the recomposition of molecular chain structure is generated and a hexatomic fused ring containing double bonds is built. The main volatile products during pyrolysis of furfural- acetone resin are H2O, and a small mount of CO, CO2 and CH4. At elevated temperatures, dehydrogenation takes place and hydrogen gas is evolved.