A series of low-temperature phase transitions of sodium aluminate solutions were studied by differential scanning calorimetry (DSC) and Raman spectroscopy. The results indicate that NaOH concentration is a primary imp...A series of low-temperature phase transitions of sodium aluminate solutions were studied by differential scanning calorimetry (DSC) and Raman spectroscopy. The results indicate that NaOH concentration is a primary impact factor for the binary eutectic point and ice melting temperature of sodium aluminate solutions with low NaOH concentration. In addition, the phase transition process of sodium aluminate solutions with low NaOH concentration from 123.15 to 283.15 K is divided into four steps: non-crystal to crystal, ternary eutectic reaction, binary eutectic reaction and ice melt. The projection phase diagram of NaOH-Al(OH)3-H2O system at low temperature was plotted, in which the ternary eutectic temperature for sodium aluminate solutions is 183.15 K.展开更多
The low-temperature spray drying technology was developed to process instant berry powder with high efficiency and higher anthocyanin retention.The maltodextrin,whey protein and inulin were selected as additives for i...The low-temperature spray drying technology was developed to process instant berry powder with high efficiency and higher anthocyanin retention.The maltodextrin,whey protein and inulin were selected as additives for instant properties formation in berry powder.The effects of inlet air temperature(40℃–80℃),vacuum degree(0.02–0.06 MPa)and additive amount on the physicochemical properties of berry powder were analyzed through solubility,anthocyanin retention and powder yield,based on moisture content and microstructure.The findings indicated that adding maltodextrin to berry enhanced the powder yield and instant solubility.Whey protein,as an additive,provided effective protection for the anthocyanins of berry powder,and the addition less than 10 g·100^(-1) g improved the powder yield.Inulin,as an additive,reduced moisture content of berry powder,which was conducive to the higher anthocyanin retention and solubility.Technique for order preference by similarity to ideal solution(TOPSIS)analysis was conducted to optimize the spray drying parameters for anthocyanin protection and solubility.The addition of 100%maltodextrin enhanced anthocyanin protection and solubility,while maintaining the desired moisture content and powder yield.This approach was used to evaluate the comprehensive quality of berry powder.This research can provide technical guidance for producing berry powder under low-temperature spray drying.展开更多
A novel Mo-doped CuO catalyst is developed and used for low-temperature NH_(3)-SCR reaction.Compared with the undoped CuO sample,the Mo doped CuO catalyst shows an increased SCR performance with above 80%NO_(x) conver...A novel Mo-doped CuO catalyst is developed and used for low-temperature NH_(3)-SCR reaction.Compared with the undoped CuO sample,the Mo doped CuO catalyst shows an increased SCR performance with above 80%NO_(x) conversion at 175℃.The XRD and Raman results have confirmed the incorporation of Mo metal ions into CuO lattice to form Mo-O-Cu species which may be related to the enhanced SCR activity.The XPS and UV-vis results reveal the creation of electron interaction between Cu and Mo in this Mo-O-Cu system which provides an increased amount of Lewis and Brønsted acid sites,thereby promoting the adsorption capacity of NH_(3) and NO_(x) as verified by NH_(3)-TPD and NO_(x)-TPD characterization.Besides,it also promotes the formation of oxygen vacancies,leading to the increasing of chemisorbed oxygen species,which improves the NO oxidation to NO_(2) activity.Furthermore,in situ DRIFTS technology was also used to study the reaction mechanism of this Mo doped CuO catalyst.The formed NO_(2) could react with NHx(x=3,2)species to enhance the low-temperature NH_(3)-SCR activity via the"fast-SCR"reaction pathway.The nitrate and nitrite ad-species may react with NH_(3) and NH4^(+)ad-species through the L-H pathway.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
A novel poly(ether ether ketone) derived from 2 (6 oxide 6H dibenz〈c, e〉〈1, 2〉oxa phospho rin 6 yl) 1,4 dihydroxyphenylene, 4, 4′ diflourodiphenylketone and bisphenol A was synthesized by solution polycondensatio...A novel poly(ether ether ketone) derived from 2 (6 oxide 6H dibenz〈c, e〉〈1, 2〉oxa phospho rin 6 yl) 1,4 dihydroxyphenylene, 4, 4′ diflourodiphenylketone and bisphenol A was synthesized by solution polycondensation. The influences of reaction time, and concentration of reactants on the polymerization were investigated . A copolymer with inherent viscosity of 1 44 was obtained. As characterized by FT IR, 1 H NMR and 31 P NMR the product was a terpolymer, consisted of bisphenol A and difluorodiphenylketone. The DSC analysis show its T g was 171 ℃. The copolymer was soluble in many polar solvents.展开更多
A monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175～180℃ for 10 h,and confirmed by FTIR,MS and elemental analysis.A s...A monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175～180℃ for 10 h,and confirmed by FTIR,MS and elemental analysis.A soluble polychloro substituted poly(aryletherketoneketone) (C-PEKK) was prepared by low temperature solution electrophilic Friedel-Crafts reaction of TCTPC and diphenyl ether (DPE) in 1,2-dichloroethane in the presence of AlCl 3 and N-methyl-2-pyrrolidinone(NMP).Effects of the molar ratio of monomers and the amounts of AlCl 3 and NMP on the polycondensation were investigated.Some propersites of the polymer was characterized by FT-IR,DSC,TGA and WAXD,etc.The results shown that the glass transition temperature(270℃) of the polymer is higher than that of pure PEEK and PEKK,and the polymer was noncrystalline.The polymer was soluble in common organic solvents such as DMF,DMSO,NMP,CHCl 3 and THF at room temperature and showed excellent thermal stability at temperature over 500℃ in air,high char yields of 61% in nitrogen and 54% in air at 700℃.展开更多
A novel unsymmetrical dianhydride containing 4\|(4\|hydroxylphenyl)\|2,3\|phthalazin\|1\|one was synthesized in order to improve the solubility of aromatic polyimides according to the principle of designing new monome...A novel unsymmetrical dianhydride containing 4\|(4\|hydroxylphenyl)\|2,3\|phthalazin\|1\|one was synthesized in order to improve the solubility of aromatic polyimides according to the principle of designing new monomers.This article reported a series of polyimide random copolymers derived from 4,4′ diamino diphenyl sulfone (DAPS),4,4′ oxyl dianiline (ODA) and the new dianhydride\|2 (3,4 dicarboxyl phenyl) 4 (3′,4′ dicarboxyl phenyl oxyl) phenyl 2,3 phthalazine 1 one dianhydride (DAH4) by“one step”solution polycondensation in m cresol with catalystic amount of isoquinoline at 200℃.Some properties of the copolymers were investigated by DSC,TG and mechanical analysis.The result shows that the η inh of copolymers is between 0 64 to 0 71 dL/g in m cresol at 25℃,and the T g of the copolymers are higher than that of pure poliymides containing 4,4′ oxyl dianiline (polymer 5).The relationship between T g and mole percent of DAPS is not obvious.Degradation temperature for 5% weight loss ( T d5 ) of the copolymers occurs all above 470℃ in air.The mechanical properties of the copolymers are lower owing to introducing sulfone groups into polymer’s backbone.In sharp contrast,the copolymers have good solubility and can be easily soluble in 1,1,2,2 tetrachloroethane(TCE), N,N dimethylacetamide(DMAc), N methyl 2 pyrrolidinone (NMP), m cresol and pyridine.Furthermore,the copolymers have better solubility in dimethyl sulfoxide (DMSO) and chloroform than the polyimide derived from DAH4 and ODA.展开更多
基金Project(51374251)supported by the National Natural Science Foundation of China
文摘A series of low-temperature phase transitions of sodium aluminate solutions were studied by differential scanning calorimetry (DSC) and Raman spectroscopy. The results indicate that NaOH concentration is a primary impact factor for the binary eutectic point and ice melting temperature of sodium aluminate solutions with low NaOH concentration. In addition, the phase transition process of sodium aluminate solutions with low NaOH concentration from 123.15 to 283.15 K is divided into four steps: non-crystal to crystal, ternary eutectic reaction, binary eutectic reaction and ice melt. The projection phase diagram of NaOH-Al(OH)3-H2O system at low temperature was plotted, in which the ternary eutectic temperature for sodium aluminate solutions is 183.15 K.
基金Supported by the National Natural Science Foundation of China(32072352)。
文摘The low-temperature spray drying technology was developed to process instant berry powder with high efficiency and higher anthocyanin retention.The maltodextrin,whey protein and inulin were selected as additives for instant properties formation in berry powder.The effects of inlet air temperature(40℃–80℃),vacuum degree(0.02–0.06 MPa)and additive amount on the physicochemical properties of berry powder were analyzed through solubility,anthocyanin retention and powder yield,based on moisture content and microstructure.The findings indicated that adding maltodextrin to berry enhanced the powder yield and instant solubility.Whey protein,as an additive,provided effective protection for the anthocyanins of berry powder,and the addition less than 10 g·100^(-1) g improved the powder yield.Inulin,as an additive,reduced moisture content of berry powder,which was conducive to the higher anthocyanin retention and solubility.Technique for order preference by similarity to ideal solution(TOPSIS)analysis was conducted to optimize the spray drying parameters for anthocyanin protection and solubility.The addition of 100%maltodextrin enhanced anthocyanin protection and solubility,while maintaining the desired moisture content and powder yield.This approach was used to evaluate the comprehensive quality of berry powder.This research can provide technical guidance for producing berry powder under low-temperature spray drying.
基金supported by the National Natural Science Foundation of China(Nos.21806017,21876019)the Fundamental Research Funds for the Central Universities(No.DUT20RC(4)003)National Key Research and Development Program of China(No.2019YFC1903903).
文摘A novel Mo-doped CuO catalyst is developed and used for low-temperature NH_(3)-SCR reaction.Compared with the undoped CuO sample,the Mo doped CuO catalyst shows an increased SCR performance with above 80%NO_(x) conversion at 175℃.The XRD and Raman results have confirmed the incorporation of Mo metal ions into CuO lattice to form Mo-O-Cu species which may be related to the enhanced SCR activity.The XPS and UV-vis results reveal the creation of electron interaction between Cu and Mo in this Mo-O-Cu system which provides an increased amount of Lewis and Brønsted acid sites,thereby promoting the adsorption capacity of NH_(3) and NO_(x) as verified by NH_(3)-TPD and NO_(x)-TPD characterization.Besides,it also promotes the formation of oxygen vacancies,leading to the increasing of chemisorbed oxygen species,which improves the NO oxidation to NO_(2) activity.Furthermore,in situ DRIFTS technology was also used to study the reaction mechanism of this Mo doped CuO catalyst.The formed NO_(2) could react with NHx(x=3,2)species to enhance the low-temperature NH_(3)-SCR activity via the"fast-SCR"reaction pathway.The nitrate and nitrite ad-species may react with NH_(3) and NH4^(+)ad-species through the L-H pathway.
文摘A novel poly(ether ether ketone) derived from 2 (6 oxide 6H dibenz〈c, e〉〈1, 2〉oxa phospho rin 6 yl) 1,4 dihydroxyphenylene, 4, 4′ diflourodiphenylketone and bisphenol A was synthesized by solution polycondensation. The influences of reaction time, and concentration of reactants on the polymerization were investigated . A copolymer with inherent viscosity of 1 44 was obtained. As characterized by FT IR, 1 H NMR and 31 P NMR the product was a terpolymer, consisted of bisphenol A and difluorodiphenylketone. The DSC analysis show its T g was 171 ℃. The copolymer was soluble in many polar solvents.
文摘A monomer of tetrachloroterephthaloyl chloride (TCTPC) was prepared by the chlorination of terephthaloyl chloride catalyzed by ferric chloride at 175～180℃ for 10 h,and confirmed by FTIR,MS and elemental analysis.A soluble polychloro substituted poly(aryletherketoneketone) (C-PEKK) was prepared by low temperature solution electrophilic Friedel-Crafts reaction of TCTPC and diphenyl ether (DPE) in 1,2-dichloroethane in the presence of AlCl 3 and N-methyl-2-pyrrolidinone(NMP).Effects of the molar ratio of monomers and the amounts of AlCl 3 and NMP on the polycondensation were investigated.Some propersites of the polymer was characterized by FT-IR,DSC,TGA and WAXD,etc.The results shown that the glass transition temperature(270℃) of the polymer is higher than that of pure PEEK and PEKK,and the polymer was noncrystalline.The polymer was soluble in common organic solvents such as DMF,DMSO,NMP,CHCl 3 and THF at room temperature and showed excellent thermal stability at temperature over 500℃ in air,high char yields of 61% in nitrogen and 54% in air at 700℃.
文摘A novel unsymmetrical dianhydride containing 4\|(4\|hydroxylphenyl)\|2,3\|phthalazin\|1\|one was synthesized in order to improve the solubility of aromatic polyimides according to the principle of designing new monomers.This article reported a series of polyimide random copolymers derived from 4,4′ diamino diphenyl sulfone (DAPS),4,4′ oxyl dianiline (ODA) and the new dianhydride\|2 (3,4 dicarboxyl phenyl) 4 (3′,4′ dicarboxyl phenyl oxyl) phenyl 2,3 phthalazine 1 one dianhydride (DAH4) by“one step”solution polycondensation in m cresol with catalystic amount of isoquinoline at 200℃.Some properties of the copolymers were investigated by DSC,TG and mechanical analysis.The result shows that the η inh of copolymers is between 0 64 to 0 71 dL/g in m cresol at 25℃,and the T g of the copolymers are higher than that of pure poliymides containing 4,4′ oxyl dianiline (polymer 5).The relationship between T g and mole percent of DAPS is not obvious.Degradation temperature for 5% weight loss ( T d5 ) of the copolymers occurs all above 470℃ in air.The mechanical properties of the copolymers are lower owing to introducing sulfone groups into polymer’s backbone.In sharp contrast,the copolymers have good solubility and can be easily soluble in 1,1,2,2 tetrachloroethane(TCE), N,N dimethylacetamide(DMAc), N methyl 2 pyrrolidinone (NMP), m cresol and pyridine.Furthermore,the copolymers have better solubility in dimethyl sulfoxide (DMSO) and chloroform than the polyimide derived from DAH4 and ODA.
