This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent. The technology of microwave curing E44 epoxy resins is inves...This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent. The technology of microwave curing E44 epoxy resins is investigated, the mechanical properties of cured epoxy resin samples in different contents of curing agent by microwave and thermal curing methods are measured respectively, and then some experimental results for which are obtained. At last, this paper analyses why microwave curing can improve mechanical property of epoxy resin.展开更多
In order to distinguish the filling effect and volcanic activity and explore the ways motivating the activity of rich-silicon iron ore tailing（IOT）, inert quartz was brought in as the correction standard, the influe...In order to distinguish the filling effect and volcanic activity and explore the ways motivating the activity of rich-silicon iron ore tailing（IOT）, inert quartz was brought in as the correction standard, the influences of fineness, calcination, thermal curing system and some other factors were investigated by IR, XRD, MIP, and so on microscopic methods. The experimental results show grinding and calcination can only change the amorphous state of SiO2, and IOT do not have volcanic activity in concrete cured under room temperature condition. Thermal curing systems can stimulate the activity of IOT, especially mortar cured by autoclave curing system can consume a large amount of Ca（OH）2 and hard calcium silicate and has a closer structure. When the specific surface area of IOT powder is 800 m^2/kg, and 30% cement is replaced by IOT powder, the mortar strength with IOT powder is even higher than that with cementonly.展开更多
Combined with the advantages of low melting point,high thermal stability and strong acidity,a multipleSO_3H functioned ionic liquid（MIL） was developed successfully as a curing agent to promote the curing reaction of...Combined with the advantages of low melting point,high thermal stability and strong acidity,a multipleSO_3H functioned ionic liquid（MIL） was developed successfully as a curing agent to promote the curing reaction of phthalonitrile-terminated poly（phthalazinone ether nitrile）（PPEN-Ph）.The curing kinetics over differential scanning calorimetry（DSC） showed that both the initial curing temperature Tp0＇ and apparent activation energy Ea＇（based on Kissinger equation） were reduced significantly over MIL（207.9℃ and 101.5 kJ/mol） compared to the common curing agent ZnCl_2（268.5℃ and 201.5 kJ/mol）.Moreover,under identical curing conditions,the resulting thermosetting resin over former（Td5%=526.1℃） showed better thermal stability than that over latter（Td5%=512.1 ℃）.These results indicated that MIL should be a good candidate as a curing agent for phthalonitrile resins.展开更多
A thermally triggered shape memory polymer composite was prepared by blending short carbon fiber（SCF） into a blend of poly（styrene-b-butadiene-b-styrene） triblock copolymer（SBS）/linear low density polyethylene（...A thermally triggered shape memory polymer composite was prepared by blending short carbon fiber（SCF） into a blend of poly（styrene-b-butadiene-b-styrene） triblock copolymer（SBS）/linear low density polyethylene（LLDPE） prior to curing. These composites have excellent processability compared with other thermosets. The dynamic mechanical analysis（DMA） and differential scanning calorimetry（DSC） were investigated to assess the thermomechanical properties of the SCF/SBS/LLDPE composite. Scanning electron microscope（SEM） imaging of the samples was performed to show the distribution of the SCF in the composite. The study specifically focused on the effect of SCF on the shape memory behavior of the SCF/SBS/LLDPE composite. The results indicated that the large amount of SCF significantly improved the mechanical property of the polymer composites while not damaging the shape memory performance. The SCF/SBS/LLDPE composites exhibited excellent shape memory behavior when the SCF content was less than 15.0 wt%. Moreover, the shape fixity ratio and shape recovery time of the SCF/SBS/LLDPE composites increased with the SCF content.展开更多
An efficient double-layer formwork curing method using an“inner supporting formwork+outer insulation formwork”was proposed in this study to address the early cracking of precast concrete components in high altitude ...An efficient double-layer formwork curing method using an“inner supporting formwork+outer insulation formwork”was proposed in this study to address the early cracking of precast concrete components in high altitude regions.Steel and plywood formwork were designed as inner support formwork,while polystyrene(PS)and polyurethane(PU)were used as outer insulation formwork.Indoor experiments and two finite element methods(The complete simulation method focuses on computational accuracy,and the equivalent simulation method emphasizes computational efficiency)were employed to analyze the evolution of the concrete temperature field under different double-layer formwork curing methods throughout the curing period,combined with compressive strength and pore structures testing.The results show that steel+5-mm-thick PU insulation formwork curing method can significantly mitigate the impact of large diurnal temperature variations on the internal temperature of concrete.Unlike traditional steam-curing,this method does not deteriorate the pore structure or compressive strength of the concrete.This study is of great significance in addressing the problem of early cracking of precast concrete components exposed to large diurnal temperature vriations in high altitude regions.展开更多
基金The research was supported by the open fund from the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(SKJ-9805)
文摘This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent. The technology of microwave curing E44 epoxy resins is investigated, the mechanical properties of cured epoxy resin samples in different contents of curing agent by microwave and thermal curing methods are measured respectively, and then some experimental results for which are obtained. At last, this paper analyses why microwave curing can improve mechanical property of epoxy resin.
基金Funded by the National Natural Science Foundation of China(51372185)
文摘In order to distinguish the filling effect and volcanic activity and explore the ways motivating the activity of rich-silicon iron ore tailing（IOT）, inert quartz was brought in as the correction standard, the influences of fineness, calcination, thermal curing system and some other factors were investigated by IR, XRD, MIP, and so on microscopic methods. The experimental results show grinding and calcination can only change the amorphous state of SiO2, and IOT do not have volcanic activity in concrete cured under room temperature condition. Thermal curing systems can stimulate the activity of IOT, especially mortar cured by autoclave curing system can consume a large amount of Ca（OH）2 and hard calcium silicate and has a closer structure. When the specific surface area of IOT powder is 800 m^2/kg, and 30% cement is replaced by IOT powder, the mortar strength with IOT powder is even higher than that with cementonly.
基金supported by National Natural Science Foundation of China(No.51273029)the Fundamental Research Funds for the Central Universities(No.DUT15RC(3)032)+1 种基金General Project of Scientific Research of the Education Department of Liaoning Province(No.L2015116)a collaborative project from Guangdong Provincial Key Laboratory of Mineral Physics and Materials(No.GLMPM-010)
文摘Combined with the advantages of low melting point,high thermal stability and strong acidity,a multipleSO_3H functioned ionic liquid（MIL） was developed successfully as a curing agent to promote the curing reaction of phthalonitrile-terminated poly（phthalazinone ether nitrile）（PPEN-Ph）.The curing kinetics over differential scanning calorimetry（DSC） showed that both the initial curing temperature Tp0＇ and apparent activation energy Ea＇（based on Kissinger equation） were reduced significantly over MIL（207.9℃ and 101.5 kJ/mol） compared to the common curing agent ZnCl_2（268.5℃ and 201.5 kJ/mol）.Moreover,under identical curing conditions,the resulting thermosetting resin over former（Td5%=526.1℃） showed better thermal stability than that over latter（Td5%=512.1 ℃）.These results indicated that MIL should be a good candidate as a curing agent for phthalonitrile resins.
基金financially supported by the National Natural Science Foundation of China(No.51403050)Fundamental Research Funds for the Central Universities of China(Nos.JB150408 and XJS15021)
文摘A thermally triggered shape memory polymer composite was prepared by blending short carbon fiber（SCF） into a blend of poly（styrene-b-butadiene-b-styrene） triblock copolymer（SBS）/linear low density polyethylene（LLDPE） prior to curing. These composites have excellent processability compared with other thermosets. The dynamic mechanical analysis（DMA） and differential scanning calorimetry（DSC） were investigated to assess the thermomechanical properties of the SCF/SBS/LLDPE composite. Scanning electron microscope（SEM） imaging of the samples was performed to show the distribution of the SCF in the composite. The study specifically focused on the effect of SCF on the shape memory behavior of the SCF/SBS/LLDPE composite. The results indicated that the large amount of SCF significantly improved the mechanical property of the polymer composites while not damaging the shape memory performance. The SCF/SBS/LLDPE composites exhibited excellent shape memory behavior when the SCF content was less than 15.0 wt%. Moreover, the shape fixity ratio and shape recovery time of the SCF/SBS/LLDPE composites increased with the SCF content.
基金support from the project of the Science and Technology Innovation Project of the Department of Transport of Yunnan Province(YJKJB[2023]150).
文摘An efficient double-layer formwork curing method using an“inner supporting formwork+outer insulation formwork”was proposed in this study to address the early cracking of precast concrete components in high altitude regions.Steel and plywood formwork were designed as inner support formwork,while polystyrene(PS)and polyurethane(PU)were used as outer insulation formwork.Indoor experiments and two finite element methods(The complete simulation method focuses on computational accuracy,and the equivalent simulation method emphasizes computational efficiency)were employed to analyze the evolution of the concrete temperature field under different double-layer formwork curing methods throughout the curing period,combined with compressive strength and pore structures testing.The results show that steel+5-mm-thick PU insulation formwork curing method can significantly mitigate the impact of large diurnal temperature variations on the internal temperature of concrete.Unlike traditional steam-curing,this method does not deteriorate the pore structure or compressive strength of the concrete.This study is of great significance in addressing the problem of early cracking of precast concrete components exposed to large diurnal temperature vriations in high altitude regions.
