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 micr...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%.展开更多
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 chan...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.展开更多
The fracture toughness of carbon fiber reinforced epoxy composite(CFRP)was investigated through mode I and mode II shaped fracture system in this paper.A novel polyimide with trifluoromethyl groups and grafted nanosil...The fracture toughness of carbon fiber reinforced epoxy composite(CFRP)was investigated through mode I and mode II shaped fracture system in this paper.A novel polyimide with trifluoromethyl groups and grafted nanosilica were used to modify epoxy resin.Effect of modified resin and unmodified resin on fracture toughness of CFRP was compared and discussed.Lay-up angles and thicknesses effects on fracture toughness of composites were also investigated.The fracture toughness of CFRP was obtained through double cantilever beam(DCB)and end notched flexure(ENF)tests.The results showed that the composites prepared by modified resin exhibited high fracture toughness compared with unmodified composites.The fracture toughness value of mode I increased from 1.83 kJ/m2 to 4.55 kJ/m2.The fracture toughness value of mode II increased from 2.30 kJ/m2 to 6.47 kJ/m2.展开更多
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-hybr...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.展开更多
Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challeng...Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challenge due to the mutual exclusivity between the dynamic and mechanical properties of materials.Here,we developed a high-strength recyclable epoxy resin(HREP)based on dynamic dithioacetal covalent adaptive network using diglycidyl ether bisphenol A(DGEBA),pentaerythritol tetra(3-mercapto-propionate)(PETMP),and vanillin epoxy resin(VEPR).At high temperatures,the exchange reaction of thermally activated dithioacetals accelerated the rearrangement of the network,giving it significant reprocessing ability.Moreover,HREP exhibited excellent solvent resistance due to the increased cross-linking density.Using this high-strength recyclable epoxy resin as the matrix and carbon fiber modified with hyperbranched ionic liquids(HBP-AMIM+PF6-)as the reinforcing agent,high performance CFRPs were successfully prepared.The tensile strength,interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of the optimized formulation(HREP20/CF-HBPPF6)were 1016.1,70.8 and 76.0 MPa,respectively.In addition,the CFRPs demonstrated excellent solvent and acid/alkali-resistance.The CFRPs could completely degrade within 24 h in DMSO at 140℃,and the recycled CF still maintained the same tensile strength and ILSS as the original after multiple degradation cycles.展开更多
The achievement of both robust fire-safety and mechanical properties is of vital requirement for carbon fiber （CF） composites. To this end, a facile interracial strategy for fabricating flame-retardant carbon fibers...The achievement of both robust fire-safety and mechanical properties is of vital requirement for carbon fiber （CF） composites. To this end, a facile interracial strategy for fabricating flame-retardant carbon fibers decorated by bio-based polyelectrolyte complexes （PEC） consisting of chitosan （CH） and ammonium polyphosphate （APP） was developed, and its corresponding fire-retarded epoxy resin composites （EP/（PEC@CF）） without any other additional flame retardants were prepared. The decorated CFs were characterized by SEM- EDX, XPS and XRD, indicating that the flame-retardant PEC coating was successfully constructed on the surface of CF. Thanks to the nitrogen- and phosphorous-containing PEC, the resulting composites exhibited excellent flame retardancy as the limiting oxygen index （LOI） increased from 31.0% of EP/CF to 40.5% and UL-94 V-0 rating was achieved with only 8.1 wt% PEC. EP/（PEC8.1@CF） also performed well in cone calorimetry with the decrease of peak-heat release rate （PHRR） and smoke production rate （SPR） by 50.0% and 30.4%, respectively, and the value of fire growth rate （FIGRA） was also reduced to 3.41 kW·m-2- s-1 from 4.84 kW· m-2· s-1, suggesting a considerably enhanced fire safety. Furthermore, SEM images of the burning residues revealed that the PEC coating exhibited the dominant flame-retardant activity in condensed phase via the formation of compact phosphorus-rich char. In addition, the impact strength of the composite was improved, together with no obvious deterioration of flexural properties and glass transition temperature. Taking advantage of the features, the PEC-decorated carbon fibers and the relevant composites fabricated by the cost-effective and facile strategy would bring more chances for widespread applications.展开更多
With the continues improving of people＇s living standards, more and more people work out in all kinds of sports fields beyond the busy work. On the other hand, the development of the modem competitive sports also req...With the continues improving of people＇s living standards, more and more people work out in all kinds of sports fields beyond the busy work. On the other hand, the development of the modem competitive sports also requires that the sports experts should not only strive for the scientific training, but should also pay much attention on the improvement and development of the sports equipment at the same time, which makes the sports equipment market have achieved unprecedented prosperity. This paper introduces the application of the fiber reinforced composite materials in the field of sports equipment, which is described mainly from the advantages of the fiber reinforced composite materials used in sports equipment areas, and from the aspects of the principles of material selection, the product varieties, the application examples and the status.展开更多
Thermoset based composites are used increasingly in industry for light weight applications, mainly for aircraft, windmills and for automobiles. Fiber reinforced thermoset polymers show a number of advantages over conv...Thermoset based composites are used increasingly in industry for light weight applications, mainly for aircraft, windmills and for automobiles. Fiber reinforced thermoset polymers show a number of advantages over conventional materials, like metals, especially their better performance regarding their strength-to-weight ratio. However, composite recycling is a big issue, as there are almost no established recycling methods. The authors investigate the recyclability of polycyanurate homo- and copolymers with different recycling agents under different conditions. Also the influence of the recycling process on the most important reinforcement fibers, i.e. carbon-, glass-, aramid-, and natural-fiber is investigated. The authors find that: the recycling speed is not only dependent on the temperature, but also is significantly influenced by the particular recycling agents and the polycyanurate formulation. Hence, the stability against the recycling media can be adjusted over a broad range by adjusting the polymer composition. Furthermore, the authors find that the inorganic reinforcement fibers (carbon and glass) are almost unaffected by neither recycling agent at either temperature. Aramid-fibers degrade, depending on the particular recycling agent, from slightly up to extremely strong. This leaves one with the possibility to find a combination of matrix resin and recycling agent, which does not affect the aramid-fiber significantly. In the case of natural fibers, the dependence on the particular recycling media is very strong: some media do not affect the fiber significantly;others reduce the mechanical properties (tensile strength and elongation at break) significantly, and still others even improve both mechanical properties strongly. From the Recyclate, the authors synthesize and subsequently characterize a number of new polyurethane thermosets (foamed and solid samples) with different contents of recyclate, exhibiting Tg in the range of 60°C to 128°C.展开更多
文摘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%.
基金Supported by Commission of Science Technology and Industry for National Defense of China(No.JPPT-115-477).
文摘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.
基金National Natural Science Foundation of China(No.11802192)Natural Science Foundation of Jiangsu Province,China(No.BK20180244)Nantong Science and Technology Project,China(No.JC2019012)。
文摘The fracture toughness of carbon fiber reinforced epoxy composite(CFRP)was investigated through mode I and mode II shaped fracture system in this paper.A novel polyimide with trifluoromethyl groups and grafted nanosilica were used to modify epoxy resin.Effect of modified resin and unmodified resin on fracture toughness of CFRP was compared and discussed.Lay-up angles and thicknesses effects on fracture toughness of composites were also investigated.The fracture toughness of CFRP was obtained through double cantilever beam(DCB)and end notched flexure(ENF)tests.The results showed that the composites prepared by modified resin exhibited high fracture toughness compared with unmodified composites.The fracture toughness value of mode I increased from 1.83 kJ/m2 to 4.55 kJ/m2.The fracture toughness value of mode II increased from 2.30 kJ/m2 to 6.47 kJ/m2.
文摘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.
基金financially supported by the National Natural Science Foundation of China(Nos.U23A2069 and 51403242)the Natural Science Foundation of Hubei Province(No.2024AFB800)+5 种基金the Fundamental Research Funds for the Central Universities,South-Central Minzu University(Nos.CZY23017 and CZD24001)the Innovation Group of National Ethnic Affairs Commission of China(No.MZR20006)the Fund for Academic Innovation Teams of South-Central Minzu University(No.XTZ24012)Scientific Research Platforms of South-Central Minzu University(No.PTZ24013)the Open Fund for Key Lab of Guangdong High Property and Functional Macromolecular Materials,China(No.20240007)State Key Laboratory of New Textile Materials and Advanced Processing Technologies(No.FZ20230012)。
文摘Recycling of carbon fiber reinforced composites is important for sustainable development and the circular economy.Despite the use of dynamic chemistry,developing high-strength recyclable CFRPs remains a major challenge due to the mutual exclusivity between the dynamic and mechanical properties of materials.Here,we developed a high-strength recyclable epoxy resin(HREP)based on dynamic dithioacetal covalent adaptive network using diglycidyl ether bisphenol A(DGEBA),pentaerythritol tetra(3-mercapto-propionate)(PETMP),and vanillin epoxy resin(VEPR).At high temperatures,the exchange reaction of thermally activated dithioacetals accelerated the rearrangement of the network,giving it significant reprocessing ability.Moreover,HREP exhibited excellent solvent resistance due to the increased cross-linking density.Using this high-strength recyclable epoxy resin as the matrix and carbon fiber modified with hyperbranched ionic liquids(HBP-AMIM+PF6-)as the reinforcing agent,high performance CFRPs were successfully prepared.The tensile strength,interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of the optimized formulation(HREP20/CF-HBPPF6)were 1016.1,70.8 and 76.0 MPa,respectively.In addition,the CFRPs demonstrated excellent solvent and acid/alkali-resistance.The CFRPs could completely degrade within 24 h in DMSO at 140℃,and the recycled CF still maintained the same tensile strength and ILSS as the original after multiple degradation cycles.
基金Financial supports by the National Natural Science Foundation of China (Nos. 51773137 and 51721091)the Sichuan Province Youth Science and Technology Innovation Team (No. 2017TD0006)
文摘The achievement of both robust fire-safety and mechanical properties is of vital requirement for carbon fiber （CF） composites. To this end, a facile interracial strategy for fabricating flame-retardant carbon fibers decorated by bio-based polyelectrolyte complexes （PEC） consisting of chitosan （CH） and ammonium polyphosphate （APP） was developed, and its corresponding fire-retarded epoxy resin composites （EP/（PEC@CF）） without any other additional flame retardants were prepared. The decorated CFs were characterized by SEM- EDX, XPS and XRD, indicating that the flame-retardant PEC coating was successfully constructed on the surface of CF. Thanks to the nitrogen- and phosphorous-containing PEC, the resulting composites exhibited excellent flame retardancy as the limiting oxygen index （LOI） increased from 31.0% of EP/CF to 40.5% and UL-94 V-0 rating was achieved with only 8.1 wt% PEC. EP/（PEC8.1@CF） also performed well in cone calorimetry with the decrease of peak-heat release rate （PHRR） and smoke production rate （SPR） by 50.0% and 30.4%, respectively, and the value of fire growth rate （FIGRA） was also reduced to 3.41 kW·m-2- s-1 from 4.84 kW· m-2· s-1, suggesting a considerably enhanced fire safety. Furthermore, SEM images of the burning residues revealed that the PEC coating exhibited the dominant flame-retardant activity in condensed phase via the formation of compact phosphorus-rich char. In addition, the impact strength of the composite was improved, together with no obvious deterioration of flexural properties and glass transition temperature. Taking advantage of the features, the PEC-decorated carbon fibers and the relevant composites fabricated by the cost-effective and facile strategy would bring more chances for widespread applications.
文摘With the continues improving of people＇s living standards, more and more people work out in all kinds of sports fields beyond the busy work. On the other hand, the development of the modem competitive sports also requires that the sports experts should not only strive for the scientific training, but should also pay much attention on the improvement and development of the sports equipment at the same time, which makes the sports equipment market have achieved unprecedented prosperity. This paper introduces the application of the fiber reinforced composite materials in the field of sports equipment, which is described mainly from the advantages of the fiber reinforced composite materials used in sports equipment areas, and from the aspects of the principles of material selection, the product varieties, the application examples and the status.
文摘Thermoset based composites are used increasingly in industry for light weight applications, mainly for aircraft, windmills and for automobiles. Fiber reinforced thermoset polymers show a number of advantages over conventional materials, like metals, especially their better performance regarding their strength-to-weight ratio. However, composite recycling is a big issue, as there are almost no established recycling methods. The authors investigate the recyclability of polycyanurate homo- and copolymers with different recycling agents under different conditions. Also the influence of the recycling process on the most important reinforcement fibers, i.e. carbon-, glass-, aramid-, and natural-fiber is investigated. The authors find that: the recycling speed is not only dependent on the temperature, but also is significantly influenced by the particular recycling agents and the polycyanurate formulation. Hence, the stability against the recycling media can be adjusted over a broad range by adjusting the polymer composition. Furthermore, the authors find that the inorganic reinforcement fibers (carbon and glass) are almost unaffected by neither recycling agent at either temperature. Aramid-fibers degrade, depending on the particular recycling agent, from slightly up to extremely strong. This leaves one with the possibility to find a combination of matrix resin and recycling agent, which does not affect the aramid-fiber significantly. In the case of natural fibers, the dependence on the particular recycling media is very strong: some media do not affect the fiber significantly;others reduce the mechanical properties (tensile strength and elongation at break) significantly, and still others even improve both mechanical properties strongly. From the Recyclate, the authors synthesize and subsequently characterize a number of new polyurethane thermosets (foamed and solid samples) with different contents of recyclate, exhibiting Tg in the range of 60°C to 128°C.
