Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,ad...Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.展开更多
In order to obtain a novel polyamide having excellent heat-resistant properties which could be anticipated as a thermal modifier for aliphatic polyamide,a series of new semi-aromatic polyamides (BO6,BO8,BO10) containi...In order to obtain a novel polyamide having excellent heat-resistant properties which could be anticipated as a thermal modifier for aliphatic polyamide,a series of new semi-aromatic polyamides (BO6,BO8,BO10) containing benzoxazole unit were synthesized based on 5-amino-2-(p-aminophenyl) benzoxazole (ABO) and aliphatic acids (adipic,suberic and sebacic acid) by means of Yamazaki phosphorylation method.The effect of reaction temperature on the inherent viscosity of the polymers was studied,and the structures of products were characterized by FTIR,1 H-NMR,and the heat resistance of the polymers was studied by DSC and TG.The results showed that the reaction temperature gives the polymers the highest viscosity at around 90 ℃,130 ℃ and 130 ℃ for BO6,BO8 and BO10,respectively.The heat resistance of the new semi-aromatic polyamides is much higher than that of the common aliphatic polyamides.In addition,the products show good solvent resistance and crystallization properties.展开更多
Aromatic copolyamides were synthesized by the Yamazaki phosphorylation method starting from bis(4- carboxyphenyl) phenyl phosphine oxide,terephthalic acid and 4,4 -diaminodiphenyl methane.The copolymers with inherent ...Aromatic copolyamides were synthesized by the Yamazaki phosphorylation method starting from bis(4- carboxyphenyl) phenyl phosphine oxide,terephthalic acid and 4,4 -diaminodiphenyl methane.The copolymers with inherent viscosities of 0.52-0.99 dL/g were obtained.The structures of the copolyamides were characterized by elemental analysis, FTIR and NMR.The glass transition temperatures were measured by DSC and DMA,respectively,and the results showed that the T_gs of the polymers were higher than 287℃.Thermal de...展开更多
Super pure 2,5-dichloroterephthaloyl dichloride (DDC) was prepared by chlorination andcontrolled by Gas Chromatography(GC) method. As a third monomer, DDC waspolycondensated into chlorinated PPTA together with terepht...Super pure 2,5-dichloroterephthaloyl dichloride (DDC) was prepared by chlorination andcontrolled by Gas Chromatography(GC) method. As a third monomer, DDC waspolycondensated into chlorinated PPTA together with terephthaloyldichloide (TPDC) andparaphenylene diamine (PPDA). The polycondensation conditions and the relationship betweenthe thermal behavior, viscosity, solubility, phase transition temperature of the modifiedpolyamide and the third monomer content discussed in this paper.展开更多
The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which...The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.展开更多
A convenient tape-casting method was applied to prepare high performance aromatic polyamide(PA)films based on Technora®.During the polycondensation,CaO was introduced to improve the solubility of the PA resin,and...A convenient tape-casting method was applied to prepare high performance aromatic polyamide(PA)films based on Technora®.During the polycondensation,CaO was introduced to improve the solubility of the PA resin,and the generated halides were totally removed from the film via a simple water bath,without leaving any defects in PA films.The factors of processing temperature and immersion time had been systematically investigated,and the experimental results demonstrated that both of them had impressive impacts on aggregation state and comprehensive properties of the PA film.It was suggested that immersion in water for more than 1 min and baking below 300℃ for 10 min were the optimal conditions for the thermal,tensile,tear,and optical properties to be in the best equilibrium.The resultant PA films integrated outstanding film-forming ability and excellent general performance,especially the tensile property and tear resistance.展开更多
A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines, and were characterized by Fourier transform infrared spectrum （FT-IR） and nuclear magnet...A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines, and were characterized by Fourier transform infrared spectrum （FT-IR） and nuclear magnetic resonance （^1H NMR）. The physical properties of the polyamides, such as glass transition temperature, melting temperature, decomposition temperature and mechanical properties were also investigated. The polyamides＇ intrinsic viscosity ranges from 1.8 dL·g^-1 to 2.2 dL·g^-1, and the melting temperature ranges from 140 ℃ to 181 ℃. The glass transition temperatures, observed from dynamic mechanical analysis, fall in the range of 34.8-48.2 ℃. The physical and mechanical properties of the resultant polyamides are similar to those of the PA1212. The heat resistance and mechanical properties of poly （4, 4′-diphenylsulfone dimeramide） （PSD） and poly（4, 4′-di pb enyl dimeramide） （PPDI） are comparable to those of PA 1212.展开更多
Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excelle...Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excellent solubility and good thermal stability.The structure of the polymer was confirmed by FT-IR and 1H NMR spectrum.The calculated degree of branching of our product was 52%.By exploring the influence of several different solvent systems,the yield of the polymer increased in the solvent system of DMAc/LiCl.Two kinds of metal complexes were obtained by chelation of the polyamide with Cu2+ and Ni2+,and the metal contents of the complexes were determined by complexometric titration.The magnetic behaviors of the complexes were examined as a function of magnetic field strength at 5 K,and as a function of temperature (5–300 K) at a magnetic field strength of 2.4 × 106 A/m.The results indicated that the complexes were soft ferromagnetic materials with Curie-Weiss temperature at 102 K and 53 K,respectively.展开更多
以己二胺为原料利用界面反应制备了双氟酰胺单体1,6-N,N′-双(4-氟苯甲酰胺)己烷(BFBH),并与硫化钠、二氯二苯砜通过溶液缩聚制备了一系列新型半芳族聚酰胺共聚改性聚芳硫醚砜(Semi-PASS/A)树脂。通过核磁氢谱(1 H NMR)和红外光谱(FTIR...以己二胺为原料利用界面反应制备了双氟酰胺单体1,6-N,N′-双(4-氟苯甲酰胺)己烷(BFBH),并与硫化钠、二氯二苯砜通过溶液缩聚制备了一系列新型半芳族聚酰胺共聚改性聚芳硫醚砜(Semi-PASS/A)树脂。通过核磁氢谱(1 H NMR)和红外光谱(FTIR)表征了单体及聚合物的化学结构。结果表明,新型单体及聚合物成功制备。Semi-PASS/A树脂的特性黏度范围为0.43~0.55 dL/g,该共聚物具有优异的热性能,其玻璃化转变温度范围为202~215℃,5%热分解温度范围为396~429℃。玻璃化转变温度、热分解温度均随着聚合物中半芳族酰胺含量的增加而下降。平板流变结果表明,Semi-PASS/A的复数黏度相比于聚芳硫醚砜树脂(PASS)下降显著,PASS树脂的25470 Pa·s降低至Semi-PASS/A-10树脂(BFBH的摩尔分数为10%)的36.9 Pa·s。随着半芳族聚酰胺含量的增加,共聚物的复数黏度降低。此外,Semi-PASS/A树脂在高温(310℃)下的时间测试中,其熔体复数黏度随时间增加基本保持稳定,表明半芳族聚酰胺引入PASS树脂结构中不仅降低了聚合物的熔体黏度,同时还有效改善了PASS的熔体稳定性,极大地改善了PASS的熔体加工性能。展开更多
基金Supported by the National Natural Science Foundation of China （20676095）the Program of Introducing Talents of Discipline to Universities （B06006）
文摘Crosslinking treatments for a commercially available aromatic polyamide reverse osmosis membrane were carried out to improve its chlorine resistance.The crosslinking agents including 1,6-hexanediol diglycidyl ether,adipoyl dichloride and hexamethylene diisocyanate ester with long flexible aliphatic chains and high reactivity with N-H groups were used in the experiments.Attenuated total reflective Fourier transform infrared spectra verified the successful preparation of highly crosslinked membranes by crosslinking treatments.It was suggested that the crosslinking agents were connected to membrane surface through the reactions with amine and amide Ⅱ groups,which is confirmed by surface charge measurements.Based on contact angle measurements,crosslinking treatments decreased membrane hydrophilicity by introducing methylene groups to membrane surface.With increasing amount of crosslinking agent molecules connected to membrane surface,the hydrolysis of unconnected functional groups of crosslinking agent produced polar groups and increased membrane hydrophilicity.The highly crosslinked membranes showed higher salt rejections and lower water fluxes as compared with the raw membrane.Since the active sites(N-H groups) vulnerable to free chlorine on membrane surface were eliminated by crosslinking treatments,the chlorine resistances of the highly crosslinked membranes were significantly improved by slighter changes in both water fluxes and salt rejections after chlorination.
基金Sponsored by the Natural Scientific Research Innovation Foundation in Harbin of Institute of Technology(Grant No. 2008. 05)
文摘In order to obtain a novel polyamide having excellent heat-resistant properties which could be anticipated as a thermal modifier for aliphatic polyamide,a series of new semi-aromatic polyamides (BO6,BO8,BO10) containing benzoxazole unit were synthesized based on 5-amino-2-(p-aminophenyl) benzoxazole (ABO) and aliphatic acids (adipic,suberic and sebacic acid) by means of Yamazaki phosphorylation method.The effect of reaction temperature on the inherent viscosity of the polymers was studied,and the structures of products were characterized by FTIR,1 H-NMR,and the heat resistance of the polymers was studied by DSC and TG.The results showed that the reaction temperature gives the polymers the highest viscosity at around 90 ℃,130 ℃ and 130 ℃ for BO6,BO8 and BO10,respectively.The heat resistance of the new semi-aromatic polyamides is much higher than that of the common aliphatic polyamides.In addition,the products show good solvent resistance and crystallization properties.
基金supported by the National Natural Science Foundation of China (No.50203008).
文摘Aromatic copolyamides were synthesized by the Yamazaki phosphorylation method starting from bis(4- carboxyphenyl) phenyl phosphine oxide,terephthalic acid and 4,4 -diaminodiphenyl methane.The copolymers with inherent viscosities of 0.52-0.99 dL/g were obtained.The structures of the copolyamides were characterized by elemental analysis, FTIR and NMR.The glass transition temperatures were measured by DSC and DMA,respectively,and the results showed that the T_gs of the polymers were higher than 287℃.Thermal de...
文摘Super pure 2,5-dichloroterephthaloyl dichloride (DDC) was prepared by chlorination andcontrolled by Gas Chromatography(GC) method. As a third monomer, DDC waspolycondensated into chlorinated PPTA together with terephthaloyldichloide (TPDC) andparaphenylene diamine (PPDA). The polycondensation conditions and the relationship betweenthe thermal behavior, viscosity, solubility, phase transition temperature of the modifiedpolyamide and the third monomer content discussed in this paper.
基金This work was supported by Academia Sinica selected Research Program and National Natural Science Foundation of China
文摘The kinetics of mesophase formation of a lyotropic aromatic polyamide from isotropic state has been studied by means of depolarized light intensity. Avrami type analysis of the data gives an exponent close to 1, which suggests the nucleation followed by one-dimensional growth. No influence of blending flexible chain from nylon 6 to the aromatic polyamide on the kinetics of mesophase formation was observed.
基金supported by the National Natural Science Foundation of China(No.51973225).
文摘A convenient tape-casting method was applied to prepare high performance aromatic polyamide(PA)films based on Technora®.During the polycondensation,CaO was introduced to improve the solubility of the PA resin,and the generated halides were totally removed from the film via a simple water bath,without leaving any defects in PA films.The factors of processing temperature and immersion time had been systematically investigated,and the experimental results demonstrated that both of them had impressive impacts on aggregation state and comprehensive properties of the PA film.It was suggested that immersion in water for more than 1 min and baking below 300℃ for 10 min were the optimal conditions for the thermal,tensile,tear,and optical properties to be in the best equilibrium.The resultant PA films integrated outstanding film-forming ability and excellent general performance,especially the tensile property and tear resistance.
文摘A series of dimer acid-based polyamides were synthesized by melt-polycondensation of dimer acid and various aromatic diamines, and were characterized by Fourier transform infrared spectrum （FT-IR） and nuclear magnetic resonance （^1H NMR）. The physical properties of the polyamides, such as glass transition temperature, melting temperature, decomposition temperature and mechanical properties were also investigated. The polyamides＇ intrinsic viscosity ranges from 1.8 dL·g^-1 to 2.2 dL·g^-1, and the melting temperature ranges from 140 ℃ to 181 ℃. The glass transition temperatures, observed from dynamic mechanical analysis, fall in the range of 34.8-48.2 ℃. The physical and mechanical properties of the resultant polyamides are similar to those of the PA1212. The heat resistance and mechanical properties of poly （4, 4′-diphenylsulfone dimeramide） （PSD） and poly（4, 4′-di pb enyl dimeramide） （PPDI） are comparable to those of PA 1212.
基金supported by the National Natural Science Foundation of China (20674071)the National Basic Research Program of China (973 Program,2005CB623800)
文摘Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excellent solubility and good thermal stability.The structure of the polymer was confirmed by FT-IR and 1H NMR spectrum.The calculated degree of branching of our product was 52%.By exploring the influence of several different solvent systems,the yield of the polymer increased in the solvent system of DMAc/LiCl.Two kinds of metal complexes were obtained by chelation of the polyamide with Cu2+ and Ni2+,and the metal contents of the complexes were determined by complexometric titration.The magnetic behaviors of the complexes were examined as a function of magnetic field strength at 5 K,and as a function of temperature (5–300 K) at a magnetic field strength of 2.4 × 106 A/m.The results indicated that the complexes were soft ferromagnetic materials with Curie-Weiss temperature at 102 K and 53 K,respectively.
