A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A（DGEBA） and flexibleα,ω-bisamino（n-alkylene）phenyl terminated poly...A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A（DGEBA） and flexibleα,ω-bisamino（n-alkylene）phenyl terminated poly（ethylene glycol）.The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers（ATPE） on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were studied.The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young’s modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.On the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA systems.The activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol;,respectively.The as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and toughness.Thus they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.展开更多
The toughening of the diglycidyl ether of bisphenol A epoxy resin with isocyanateterminated polyethers （ITPE） was investigated. The progress of the reaction and the structural changes during modification process wer...The toughening of the diglycidyl ether of bisphenol A epoxy resin with isocyanateterminated polyethers （ITPE） was investigated. The progress of the reaction and the structural changes during modification process were studied using FTIR spectroscopy. The studies support the proposition that TDI （tolylene diisocyanate） acts as a coupling agent between the epoxy and polyethers, forming a urethane linkage with the former and the latter, respectively. Me THPA-cured ER/ITPs blends were characterized using dynamic mechanical analysis （DMA） and thermogravimetric analysis （TGA）. It is indicated the glass transition temperature （T） of systems was lower than the T of pure epoxy resin and overfull ITPE separated from the modified epoxy resin and formed another phase at an ITPE-content of more than 10wt%. The thermal stability was decreased by the introduction of ITPE. The impact strength and the flexural strength of the cured modifiedepoxy increased with increasing the ITPE content and a maximum plateau value of about 24.03 kJ/m^2 and 130.56 MPa was measured in 10wt% ITPE. From scanning electron microscopy （SEM） studies of the fractrue surfaces of ER/ITPE systems, the nature of the micromechanisms responsible for the increases in toughness of the systems was identified.展开更多
The synthesis of eight new arsamacrocyclic Polyethers was described. The structures of these compounds were characterized by elemental analysis, IR, H-1-NMR and MS.
Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potass...Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.展开更多
将氢氧化钠作为沉淀剂,以无水氯化镁为原料,采用双向沉淀法制备超细氢氧化镁(MH),在制备过程中引入硅聚醚使氢氧化镁表面有机化。考察了硅聚醚的添加方式、硅聚醚的添加量、反应温度和搅拌速度等因素对氢氧化镁浆料的过滤性能的影响。...将氢氧化钠作为沉淀剂,以无水氯化镁为原料,采用双向沉淀法制备超细氢氧化镁(MH),在制备过程中引入硅聚醚使氢氧化镁表面有机化。考察了硅聚醚的添加方式、硅聚醚的添加量、反应温度和搅拌速度等因素对氢氧化镁浆料的过滤性能的影响。利用接触角测定仪、纳米粒度及Zeta电位分析仪、傅里叶红外光谱仪、同步热分析仪等对氢氧化镁粉体的接触角、粒径、表面结构和热稳定性进行了表征。研究结果表明:在硅聚醚的添加方式为在氢氧化钠溶液中添加硅聚醚[Mg(OH)_(2)-Ⅱ],每100 g MH中硅聚醚的添加量为3 g,反应温度为60℃,搅拌速度为800 r/min的条件下,氢氧化镁浆料的过滤性能最好,过滤速度最快为4.79×10^(-4)m/s;在最佳条件下制备的氢氧化镁的接触角比未改性氢氧化镁提高了6倍多;FT-IR分析证明了硅聚醚成功地吸附在氢氧化镁的表面;热分析表明了改性氢氧化镁的热稳定性明显提高。展开更多
基金supported by the National 863 Plan(No.2006AA03A209)New Century Excellent Talent Plan (No.NECT-05-0660) from Ministry of EducationDefense Basic Research Item(No.D1420061057)
文摘A high performance thermosetting epoxy resin crosslinkable at room temperature was obtained via directly moulding diglycidyl ether of bisphenol A（DGEBA） and flexibleα,ω-bisamino（n-alkylene）phenyl terminated poly（ethylene glycol）.The influences of the n-alkylene inserted in aminophenyl of flexible amino-terminated polythers（ATPE） on the mechanical properties,fractographs and curing kinetics of the ATPE-DGEBA cured products were studied.The results show that the insertion of n-alkylene group into the aminophenyl group of the ATPE,on one hand,can significantly increase the strain relaxation rate and decrease glass transition temperature of the ATPE-DGEBA cured products,resulting in slight decrease of the Young’s modulus and tensile strength,and significant increase of the toughness and elongation of the ATPE-DGEBA cured products.On the other hand,it can remarkably enhance the reactivity of amine with epoxy,much accelerating the curing rate of the ATPE-DGEBA systems.The activation energy of DGEBA cured by BAPTPE,BAMPTPE and BAEPTPE was 53.1,28.5 and 25.4 kJ·mol;,respectively.The as-obtained ATPE-DGEBA cured products are homogeneous, transparent,and show excellent mechanical properties including tensile strength and toughness.Thus they are promising to have important applications in structure adhesives,casting bulk materials,functional coatings,cryogenic engineering, damping and sound absorbing materials.
基金the Natural Science Foundation of Hubei Province (No.2006ABA321)
文摘The toughening of the diglycidyl ether of bisphenol A epoxy resin with isocyanateterminated polyethers （ITPE） was investigated. The progress of the reaction and the structural changes during modification process were studied using FTIR spectroscopy. The studies support the proposition that TDI （tolylene diisocyanate） acts as a coupling agent between the epoxy and polyethers, forming a urethane linkage with the former and the latter, respectively. Me THPA-cured ER/ITPs blends were characterized using dynamic mechanical analysis （DMA） and thermogravimetric analysis （TGA）. It is indicated the glass transition temperature （T） of systems was lower than the T of pure epoxy resin and overfull ITPE separated from the modified epoxy resin and formed another phase at an ITPE-content of more than 10wt%. The thermal stability was decreased by the introduction of ITPE. The impact strength and the flexural strength of the cured modifiedepoxy increased with increasing the ITPE content and a maximum plateau value of about 24.03 kJ/m^2 and 130.56 MPa was measured in 10wt% ITPE. From scanning electron microscopy （SEM） studies of the fractrue surfaces of ER/ITPE systems, the nature of the micromechanisms responsible for the increases in toughness of the systems was identified.
文摘The synthesis of eight new arsamacrocyclic Polyethers was described. The structures of these compounds were characterized by elemental analysis, IR, H-1-NMR and MS.
文摘Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.
文摘将氢氧化钠作为沉淀剂,以无水氯化镁为原料,采用双向沉淀法制备超细氢氧化镁(MH),在制备过程中引入硅聚醚使氢氧化镁表面有机化。考察了硅聚醚的添加方式、硅聚醚的添加量、反应温度和搅拌速度等因素对氢氧化镁浆料的过滤性能的影响。利用接触角测定仪、纳米粒度及Zeta电位分析仪、傅里叶红外光谱仪、同步热分析仪等对氢氧化镁粉体的接触角、粒径、表面结构和热稳定性进行了表征。研究结果表明:在硅聚醚的添加方式为在氢氧化钠溶液中添加硅聚醚[Mg(OH)_(2)-Ⅱ],每100 g MH中硅聚醚的添加量为3 g,反应温度为60℃,搅拌速度为800 r/min的条件下,氢氧化镁浆料的过滤性能最好,过滤速度最快为4.79×10^(-4)m/s;在最佳条件下制备的氢氧化镁的接触角比未改性氢氧化镁提高了6倍多;FT-IR分析证明了硅聚醚成功地吸附在氢氧化镁的表面;热分析表明了改性氢氧化镁的热稳定性明显提高。
