Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the inte...Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.展开更多
Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly ...Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.展开更多
It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranc...It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranched toughener,carboxylic acid-functionalized tannic acid(CATA),was successfully prepared and applicated to the preparation of solvent-free epoxy resins.The mechanical performance,morphology,structural characterization,and thermal characterization of toughened epoxy resin system were studied.The toughened epoxy resin system with only 1.0wt%CATA reached the highest impact strength,111%higher than the neat epoxy resin system.Notably,the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading.Nonphase-separated hybrids with significant toughening effect were obtained.Additionally,the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading.This study provides an eco-friendly,cost-effective,and facile approach for the preparation of high-performance,solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields.展开更多
A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composi...A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition upon the performance such as apparent viscosity,film behaviors,and adhesion capacity to fibers for warp sizing operation.The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method,the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength,breaking elongation,solution time and hygroscopic capacity.It was found that the viscosity,adhesion capability,glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio.Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance.A favorable mole ratio of vinyl acetate or acrylamide was found to be 45∶55.Based on this mole ratio,the adhesion capability and film behaviors of the sizing agent reach their maximal values simultaneously.This demonstrates that the sizing agent should be synthesized under this copolymer composition from the viewpoint of adhesion and film behaviors.展开更多
The adhesion between warp sizing and fiber was systematically studied by using the roving method.Cotton roving and polyester roving were sized with various concentrations between 0.01%and 2.50%of acid-thinned starch,p...The adhesion between warp sizing and fiber was systematically studied by using the roving method.Cotton roving and polyester roving were sized with various concentrations between 0.01%and 2.50%of acid-thinned starch,polyvinyl alcohol and water-soluble polyester sizing,respectively,and tensile property of the sized roving was tested accordingly.The break force of the sized roving was considered as the adhesion force of the sizing to the fiber in the roving method.The experimental results show that the effects of sizing film strength and fiber strength on the adhesive force can be weakened when the concentration 0.5%of size paste is used,instead of 1%in the roving method.The size morphology in the sized roving and on the surface was observed through scanning electron microscopy,in the form of penetration and coverage of the sizing in or on the roving.On the other hand,the Young-Dupréequation was used to calculate the adhesion work.The advantages and disadvantages of roving method and the adhesion work method were compared.The adhesion obtained by both two methods reflects the rule of chemical similarity between warp sizing and fiber.展开更多
A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies s...A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies show that the synthetic method used in this paper was a new way and had never been found in the synthesis of acrylate sizing agent, and that the properties of those new-type size-agent were be improved, which had potential for substituting PVA (polyvinyl alcohol) sizing agent. The technology for solving the problem of nano-scale powder agglomeration and dispersion were also studied. The transmission electron microscope (TEM) observation showed that nano-TiO2had good dispersion and stability in aqueous solution and in sizing agent solution.展开更多
In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments we...In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments were,respectively,conducted in Peking(50 m,101.2 kPa)and Lhasa(3,650 m,63.1 kPa).Surface tensions and inflection-point concentrations were tested based on AEA solutions,whilst developmental characteristics,thicknesses and elastic coefficients of liquid films were tested based on air bubbles of AEA solutions.The study involved three types of AEAs,which were TM-O,226A,and 226S.The experimental results show that initial sizes of TM-O,226A,and 226S are,respectively,increased by 43.5%,17.5%,and 3.8%.With the decrease of ambient pressure,the drainage rate and the drainage index of AEA solution bubbles increase.Interference experiments show that the liquid film thicknesses of all tested AEA solution bubbles are in micron scales.When the atmospheric pressure decreases from 101.2 to 63.1 kPa,the liquid film thicknesses of three types of AEA solutions decrease in various degrees;and film elasticities at critical thicknesses increase.Liquid film of 226S solution bubbles is the most stable,presenting as a minimum thickness variation.It should be noted that elastic coefficient of liquid film only represents the level at critical thickness,thus it can not be applied as the only evaluating indicator of bubble stability.For a type of AEA,factors affecting the stability of its bubbles under low atmospheric pressure include initial bubbles size,liquid film thickness,liquid film elasticity,ambient temperature,etc.展开更多
The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was expl...The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was explained by oxygen spectrum nuclear magnetic resonance(17O-NMR)experiments and capillarity analysis.The results of the LF-NMR experiment show that the nano-sized oil-displacement agent iNanoW1.0 could increase the swept volume by 10%-20%on the basis of conventional water flooding,making water molecules get into the low permeable region with small pores that conventional water flooding could not reach.17O-NMR technique and capillary analysis proved that iNanoW1.0 nanoparticles could weaken the association of hydrogen bonds between water molecules,effectively change the structure of water molecular clusters,and thus increasing the swept volume in the low permeable region.The ability of weakening association of hydrogen bonds between water molecules of iNanoW1.0 nanoparticles increases with its mass fraction and tends to be stable after the mass fraction of 0.1%.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U22A20252 and 52173076)the Beijing Natural Science Foundation(Nos.Z240030 and L248023)the Liaoning Province Key Research and Development Project(No.2024JH2/102400046)。
文摘Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.
文摘Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.
基金from the Special Fund for the Program for Zhejiang Provincial Natural Science Foundation of China(LZ16C160001)National Key Research and Development Program(2017YFD0601105),the National Natural Science Foundation of China(Grant No.21806142)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LY20B070002).
文摘It is essential to design economic and efficient tougheners to prepare high-performance epoxy resin;however,this has remained a huge challenge.Herein,an eco-friendly,low-cost,and facile-fabricated bio-based hyperbranched toughener,carboxylic acid-functionalized tannic acid(CATA),was successfully prepared and applicated to the preparation of solvent-free epoxy resins.The mechanical performance,morphology,structural characterization,and thermal characterization of toughened epoxy resin system were studied.The toughened epoxy resin system with only 1.0wt%CATA reached the highest impact strength,111%higher than the neat epoxy resin system.Notably,the tensile strength and elongation at break of toughened epoxy resin systems increased moderately with increasing CATA loading.Nonphase-separated hybrids with significant toughening effect were obtained.Additionally,the thermal stabilities of toughened epoxy resin systems decreased with increasing CATA loading.This study provides an eco-friendly,cost-effective,and facile approach for the preparation of high-performance,solvent-free epoxy resins with potential for practical applications in sealing integrated circuits and electrical devices fields.
基金The Foundation of Talented Persons in Anhui Province(No.2002Z036)
文摘A series of poly(vinyl acetate-co-acrylamide)copolymers with different mole ratios of vinyl acetate to acrylamide units were synthesized by emulsion polymerization for investigating the influences of copolymer composition upon the performance such as apparent viscosity,film behaviors,and adhesion capacity to fibers for warp sizing operation.The mole ratios of vinyl acetate to acrylamide were varied from 0 to 4.By using an impregnated roving method,the adhesion was evaluated in terms of the maximal strength and work to break of a slightly sized roving.The film behaviors included breaking strength,breaking elongation,solution time and hygroscopic capacity.It was found that the viscosity,adhesion capability,glass transition temperature and film behaviors of the copolymeric sizing agent strongly depended on the mole ratio.Excessively increasing the amounts of vinyl acetate or acrylamide units incorporated into the copolymeric chains damages much of the performance.A favorable mole ratio of vinyl acetate or acrylamide was found to be 45∶55.Based on this mole ratio,the adhesion capability and film behaviors of the sizing agent reach their maximal values simultaneously.This demonstrates that the sizing agent should be synthesized under this copolymer composition from the viewpoint of adhesion and film behaviors.
基金Funded by the National Natural Science Foundation of China(51903178)the Sichuan University Experiment Technique Projects(SCU201129)。
文摘The adhesion between warp sizing and fiber was systematically studied by using the roving method.Cotton roving and polyester roving were sized with various concentrations between 0.01%and 2.50%of acid-thinned starch,polyvinyl alcohol and water-soluble polyester sizing,respectively,and tensile property of the sized roving was tested accordingly.The break force of the sized roving was considered as the adhesion force of the sizing to the fiber in the roving method.The experimental results show that the effects of sizing film strength and fiber strength on the adhesive force can be weakened when the concentration 0.5%of size paste is used,instead of 1%in the roving method.The size morphology in the sized roving and on the surface was observed through scanning electron microscopy,in the form of penetration and coverage of the sizing in or on the roving.On the other hand,the Young-Dupréequation was used to calculate the adhesion work.The advantages and disadvantages of roving method and the adhesion work method were compared.The adhesion obtained by both two methods reflects the rule of chemical similarity between warp sizing and fiber.
基金Science and Technology Bureau of Nangtong in Jiangsu Province,China(No.A5035)Depart ment of Education,Jiangsu Province,China(No.J HZD06-30)
文摘A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc. by orthogonal design method. Results of the studies show that the synthetic method used in this paper was a new way and had never been found in the synthesis of acrylate sizing agent, and that the properties of those new-type size-agent were be improved, which had potential for substituting PVA (polyvinyl alcohol) sizing agent. The technology for solving the problem of nano-scale powder agglomeration and dispersion were also studied. The transmission electron microscope (TEM) observation showed that nano-TiO2had good dispersion and stability in aqueous solution and in sizing agent solution.
基金Funded by the National Natural Science Foundation of China(Nos.52178428,52178427,and 52308454)the Science and Technology Project of Tibet Department of Transportation(No.XZJTKJ[2020]04)。
文摘In order to ascertain the effects of atmospheric pressure on developmental characteristics and the stability of AEA(air-entraining agent)solution bubbles,AEA solution experiments and AEA solution bubble experiments were,respectively,conducted in Peking(50 m,101.2 kPa)and Lhasa(3,650 m,63.1 kPa).Surface tensions and inflection-point concentrations were tested based on AEA solutions,whilst developmental characteristics,thicknesses and elastic coefficients of liquid films were tested based on air bubbles of AEA solutions.The study involved three types of AEAs,which were TM-O,226A,and 226S.The experimental results show that initial sizes of TM-O,226A,and 226S are,respectively,increased by 43.5%,17.5%,and 3.8%.With the decrease of ambient pressure,the drainage rate and the drainage index of AEA solution bubbles increase.Interference experiments show that the liquid film thicknesses of all tested AEA solution bubbles are in micron scales.When the atmospheric pressure decreases from 101.2 to 63.1 kPa,the liquid film thicknesses of three types of AEA solutions decrease in various degrees;and film elasticities at critical thicknesses increase.Liquid film of 226S solution bubbles is the most stable,presenting as a minimum thickness variation.It should be noted that elastic coefficient of liquid film only represents the level at critical thickness,thus it can not be applied as the only evaluating indicator of bubble stability.For a type of AEA,factors affecting the stability of its bubbles under low atmospheric pressure include initial bubbles size,liquid film thickness,liquid film elasticity,ambient temperature,etc.
基金Supported by the PetroChina Scientifc Research and Technological Development Project(2018A-0907).
文摘The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was explained by oxygen spectrum nuclear magnetic resonance(17O-NMR)experiments and capillarity analysis.The results of the LF-NMR experiment show that the nano-sized oil-displacement agent iNanoW1.0 could increase the swept volume by 10%-20%on the basis of conventional water flooding,making water molecules get into the low permeable region with small pores that conventional water flooding could not reach.17O-NMR technique and capillary analysis proved that iNanoW1.0 nanoparticles could weaken the association of hydrogen bonds between water molecules,effectively change the structure of water molecular clusters,and thus increasing the swept volume in the low permeable region.The ability of weakening association of hydrogen bonds between water molecules of iNanoW1.0 nanoparticles increases with its mass fraction and tends to be stable after the mass fraction of 0.1%.
