Catalysis effect of triphenyl bismuth （TPB） on kinetics of hydroxyl terminated polybutadiene-toluene diisocyanate （HTPB-TDI） curing reaction was studied by non-isothermal differential scanning calorimetry （DSC）....Catalysis effect of triphenyl bismuth （TPB） on kinetics of hydroxyl terminated polybutadiene-toluene diisocyanate （HTPB-TDI） curing reaction was studied by non-isothermal differential scanning calorimetry （DSC）. The characteristic temperature of curing system was measured for calculating kinetic parameters and establishing curing reaction kinetic equations. The results show that activation energy （Ea） of uncatalyzed HTPB-TDI curing system is 51.29 kJmol-1, and TPB decreases Ea to 46.43 kJ＇mol-1. Catalyst lowers reaction temperature and shortens curing time through decreasing ac- tivation energy of curing reaction and accelerating reaction rate. TPB can increase the reaction rate at 27 ℃ to the value of uncatalyzed system at 80 ℃. The catalytic activity reaches the maximum when concentration is 0.5 %.展开更多
A kind of catalyst, ammonium molybdate was developed in this paper to promote the curing reaction of bisphthalonitrile resins with aromatic amine as curing agent, and the catalytic effect was studied by differential s...A kind of catalyst, ammonium molybdate was developed in this paper to promote the curing reaction of bisphthalonitrile resins with aromatic amine as curing agent, and the catalytic effect was studied by differential scanning calorimetry （DSC）, rheometric measurements and thermogravimetric analysis （TGA）. The results indicated that the catalyst could improve the curing rate and increase the curing degree, which could be regulated by the content of the catalyst used in the reaction.展开更多
A series of phthalonitrile blending resins were prepared from 4-aminophenoxyphthalonitrile(APN) and 4,4'-bis(3,4- dicyanophenoxy)biphenyl(BPH) by directly powder-mixing and copolymerization.Differential scanning c...A series of phthalonitrile blending resins were prepared from 4-aminophenoxyphthalonitrile(APN) and 4,4'-bis(3,4- dicyanophenoxy)biphenyl(BPH) by directly powder-mixing and copolymerization.Differential scanning calorimeter(DSC) and dynamic rheology were used to study the curing reaction behaviors of APN/BPH blends,and the results indicated that the introduction of APN accelerated the curing rate of BPH,and the existence of BPH decreased the curing temperature of APN/BPH systems.The thermal stability of postcured APN/BPH resins was investigated by thermogravimetric analysis(TGA),and the TGA results indicated that the crosslinked polymers of APN/BPH systems possessed good thermal stability.展开更多
In this study on the curing dynamics of phenol-formaldehyde novolac resins(PFNR) and hexamethylene tetramine(HMTA), two typical commercial PFNR were selected as examples and the curing reactions of the resins with HMT...In this study on the curing dynamics of phenol-formaldehyde novolac resins(PFNR) and hexamethylene tetramine(HMTA), two typical commercial PFNR were selected as examples and the curing reactions of the resins with HMTA were studied by differential scanning calorimetry(DSC). Based on the data calculated by the Kissinger equation and the Crane equation, a thermocuring dynamic model was established, from which the process conditions, activation energy, reaction kinetics equation and a f irst-order reaction of the curing reactions were derived.展开更多
In order to understand the strength developing law of the epoxy asphalt mixture,a curing reaction model of the epoxy asphalt binder was proposed based upon the thermokinetic analysis.Given some assumptions,the model w...In order to understand the strength developing law of the epoxy asphalt mixture,a curing reaction model of the epoxy asphalt binder was proposed based upon the thermokinetic analysis.Given some assumptions,the model was developed by applying the Kissinger law as well as Arrhenius equation,and the differential scanning calorimetry was performed for estimating the model parameters.To monitor the strength development of the epoxy asphalt mixture,a strength test program was employed and then results were compared to those produced from the proposed model.The comparative evaluation shows that a good consistency exists between the outputs from test program and the proposed model,indicating that the proposed model can be used effectively for simulating the curing reaction process for the epoxy asphalt binder and predicting the strength development for the epoxy asphalt mixture.展开更多
Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations)...Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model.展开更多
The rheological behavior of bismaleimide resin for resin transfer molding(RTM) was studied with DSC analysis and viscosity experiments A rheological model based on the dual Arrhenius equation was established and used ...The rheological behavior of bismaleimide resin for resin transfer molding(RTM) was studied with DSC analysis and viscosity experiments A rheological model based on the dual Arrhenius equation was established and used to simulate the rheological behavior of the resin The model predictions determined from the dual Arrhenius equation were in good agreement with experimental data The processing window of the resin system can be well determined based on the developed model The rheological model is importan...展开更多
The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechani...The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.展开更多
We introduce a reaction model for use in coarse-grained simulations to study the chemical reactions in polymer systems at mesoscopic level.In this model,we employ an idea of reaction probability in control of the whol...We introduce a reaction model for use in coarse-grained simulations to study the chemical reactions in polymer systems at mesoscopic level.In this model,we employ an idea of reaction probability in control of the whole process of chemical reactions.This model has been successfully applied to the studies of surface initiated polymerization process and the network structure formation of typical epoxy resin systems.It can be further modified to study different kinds of chemical reactions at mesoscopic scale.展开更多
文摘Catalysis effect of triphenyl bismuth （TPB） on kinetics of hydroxyl terminated polybutadiene-toluene diisocyanate （HTPB-TDI） curing reaction was studied by non-isothermal differential scanning calorimetry （DSC）. The characteristic temperature of curing system was measured for calculating kinetic parameters and establishing curing reaction kinetic equations. The results show that activation energy （Ea） of uncatalyzed HTPB-TDI curing system is 51.29 kJmol-1, and TPB decreases Ea to 46.43 kJ＇mol-1. Catalyst lowers reaction temperature and shortens curing time through decreasing ac- tivation energy of curing reaction and accelerating reaction rate. TPB can increase the reaction rate at 27 ℃ to the value of uncatalyzed system at 80 ℃. The catalytic activity reaches the maximum when concentration is 0.5 %.
文摘A kind of catalyst, ammonium molybdate was developed in this paper to promote the curing reaction of bisphthalonitrile resins with aromatic amine as curing agent, and the catalytic effect was studied by differential scanning calorimetry （DSC）, rheometric measurements and thermogravimetric analysis （TGA）. The results indicated that the catalyst could improve the curing rate and increase the curing degree, which could be regulated by the content of the catalyst used in the reaction.
文摘A series of phthalonitrile blending resins were prepared from 4-aminophenoxyphthalonitrile(APN) and 4,4'-bis(3,4- dicyanophenoxy)biphenyl(BPH) by directly powder-mixing and copolymerization.Differential scanning calorimeter(DSC) and dynamic rheology were used to study the curing reaction behaviors of APN/BPH blends,and the results indicated that the introduction of APN accelerated the curing rate of BPH,and the existence of BPH decreased the curing temperature of APN/BPH systems.The thermal stability of postcured APN/BPH resins was investigated by thermogravimetric analysis(TGA),and the TGA results indicated that the crosslinked polymers of APN/BPH systems possessed good thermal stability.
基金financially supported by the Fundamental Research Funds for the Central Universities of China(SWU.113003 and XDJK 2015C097)
文摘In this study on the curing dynamics of phenol-formaldehyde novolac resins(PFNR) and hexamethylene tetramine(HMTA), two typical commercial PFNR were selected as examples and the curing reactions of the resins with HMTA were studied by differential scanning calorimetry(DSC). Based on the data calculated by the Kissinger equation and the Crane equation, a thermocuring dynamic model was established, from which the process conditions, activation energy, reaction kinetics equation and a f irst-order reaction of the curing reactions were derived.
基金Funded by the Project of National Science and Technology Ministry of China(No.2009BAG15B03)
文摘In order to understand the strength developing law of the epoxy asphalt mixture,a curing reaction model of the epoxy asphalt binder was proposed based upon the thermokinetic analysis.Given some assumptions,the model was developed by applying the Kissinger law as well as Arrhenius equation,and the differential scanning calorimetry was performed for estimating the model parameters.To monitor the strength development of the epoxy asphalt mixture,a strength test program was employed and then results were compared to those produced from the proposed model.The comparative evaluation shows that a good consistency exists between the outputs from test program and the proposed model,indicating that the proposed model can be used effectively for simulating the curing reaction process for the epoxy asphalt binder and predicting the strength development for the epoxy asphalt mixture.
文摘Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model.
基金National Natural Science F oundation of China(5 983 3 110 ) National Defence Foundation(0 0 j0 0 .5 .3 .hk0 14 4)
文摘The rheological behavior of bismaleimide resin for resin transfer molding(RTM) was studied with DSC analysis and viscosity experiments A rheological model based on the dual Arrhenius equation was established and used to simulate the rheological behavior of the resin The model predictions determined from the dual Arrhenius equation were in good agreement with experimental data The processing window of the resin system can be well determined based on the developed model The rheological model is importan...
基金This study is partially supported by the National Natural Science Foundation of China.
文摘The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl ether of bisphenol A) (DGEBA) and poly(ethylene oxide) (PEG) and crosslinked by phthalic anhydride (PA) was studied using dynamic mechanical method. Single glass transition temperatures intermediate between the two pure components were observed for all blend levels. The secondary relaxation mechanism should relate to not only diester linkage, but also hydroxyether structural unit in the system. Fourier transform infrared spectroscopy (FTIR) is applied to study the curing reaction and intermolecular specific interaction of the system. The results indicate the PEO participates the crosslinking reaction, accelerates the curing reaction and make the reaction more perfect. The shifts of the hydroxyl band and carbonyl band demonstrate the presence of the intermolecular interaction in the cured blend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyether units and the ether bond in PEO macromolecules is stronger.
基金the support of the National Natural Science Foundation of China(Grant Nos.21025416,20974040,50930001)China Postdoctoral Science Foundation(Grant No.20110491295).
文摘We introduce a reaction model for use in coarse-grained simulations to study the chemical reactions in polymer systems at mesoscopic level.In this model,we employ an idea of reaction probability in control of the whole process of chemical reactions.This model has been successfully applied to the studies of surface initiated polymerization process and the network structure formation of typical epoxy resin systems.It can be further modified to study different kinds of chemical reactions at mesoscopic scale.
