Water pollution caused by Hg(II)and Ag(I)poses deleterious effects to environmental safety.Adsorption is one of the promising methods to decontaminate aqueous metal ions.Herein,polyhydroxyl-capped poly(amidoamine)(PAM...Water pollution caused by Hg(II)and Ag(I)poses deleterious effects to environmental safety.Adsorption is one of the promising methods to decontaminate aqueous metal ions.Herein,polyhydroxyl-capped poly(amidoamine)(PAMAM)dendrimer/silica composites(G1-OH and G2-OH)were prepared for decontaminating aqueous Hg(II)and Ag(I).The maximum adsorption capacity of G1-OH and G2-OH for Hg(II)are 0.45 and 0.76 mmol/g,while that for Ag(I)are 0.66 and 0.81 mmol/g.The optimum solution pH for the adsorption of Hg(II)and Ag(I)are both 6.The adsorption for Hg(II)and Ag(I)can reach equilibrium at150 and 120 min,respectively.Pseudo-second-order model can be used to describe the adsorption kinetic process and the rate-controlling step is film diffusion process.Adsorption isotherm indicates the adsorption can be promoted by increasing concentration and temperature,and the adsorption process could be described by Langmuir model with chemical mechanism.G1-OH and G2-OH exhibit excellent adsorption selectivity and they can 100%adsorb Hg(II)or Ag(I)with the coexisting of Fe(III),Co(II),Cu(II)or Ni(II).Adsorption mechanism confirms C-N,OH and CONH groups play critical role for the adsorption of the two ions.The work may provide efficient adsorbents for the decontamination of aqueous Hg(II)and Ag(I)with practical value.展开更多
An azyl group of ethylene diamine was protected by N-tert-butoxycarbonyl.The remaining azyl group then successively reacted with methyl acrylate, ethylene diamine and methyl acrylate again to afford the compound Boc-N...An azyl group of ethylene diamine was protected by N-tert-butoxycarbonyl.The remaining azyl group then successively reacted with methyl acrylate, ethylene diamine and methyl acrylate again to afford the compound Boc-NH 2-(B-COOCH 3) 4 3 (AB-4).The ester groups and the Boc-end group of 3 were transferred to carboxylate 4 and azyl group 5 via hydrolyzation and deprotection respectively.The fan-shape dendron molecules with 16 exterior groups 6 were obtained by condensation of 4 and 5 in the presence of DCC.The dumbbell-like dendrimer molecules 7 could expediently prepared by coupling the dendrons with two functional groups of hexanedioyl chloride.The paper describes the synthesis procedures,reports the characterization results of FTIR、 1H-NMR、 13C-NMR and MALDI-TOF.Comparing with the PAMAM dendrimers from the divergent method, the synthesized compounds possess accurate structures and few defections.展开更多
The curing process of dendritic polymer PAMAM with bis-phenol A epoxy resin was investigated using isothermal differential scanning calorimetry（DSC）,the mechanism of this reaction was autocatalytic.The data of two r...The curing process of dendritic polymer PAMAM with bis-phenol A epoxy resin was investigated using isothermal differential scanning calorimetry（DSC）,the mechanism of this reaction was autocatalytic.The data of two reaction rate constants k1,k2 and reaction orders m,n were obtained from Kamal equation.The overall reaction order m+n was between 2.07 and 2.29,the apparent activation energies of E1 and E2 were 59.79 kJ/mol and 56.51 kJ/mol, respectively.The reaction entered into a diffusion controlled stage at the conversion of 50%,experimental data and theoretic curve had deviation at this time.The reaction conversion,at which the deviation occurred,decreased with lowering curing temperature.展开更多
H 2PtCl 6 was coordinated with the carboxyl-terminated G4.5PAMAM dendrimer molecules (PAMAMC) in aqueous solution,followed by reduction using NaBH 4 as reducer,and formed Pt-PAMAMC hybrid nano-particles.The stable mul...H 2PtCl 6 was coordinated with the carboxyl-terminated G4.5PAMAM dendrimer molecules (PAMAMC) in aqueous solution,followed by reduction using NaBH 4 as reducer,and formed Pt-PAMAMC hybrid nano-particles.The stable multilayer films were obtained by fabricating diazo resin(DR) with these hybrid nanoparticles (Pt-PAMAMC) and PAMAMC,respectively.The films were subsequently irradiated under UV-light.It was found that the films from Pt-PAMAMC as polyanions exhibit stable frictional responses under the applied load,and the lubricative property of the films from Pt-PAMAMC hybrid nanoparticles is obviously superior to that of the films from dendrimer without platinum inside.展开更多
Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photolumi...Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photoluminescence was purple. The room temperature photoluminescence quantum yield (RT-PQY) was 0.015. The diameter of CdS QDs increased with the increase of n / nPAMAM, also the color of photoluminescence was tunable and could be changed from purple to blue.展开更多
基金supported by National Natural Science Foundation of China(No.22278201)Youth Innovation Team Development Plan of Universities in Shandong Province,Fundamental Research Projects of Science&Technology Innovation and Development Plan in Yantai City(No.2022JCYJ030)+1 种基金the Science Fund of Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(No.AMGM2023F09)the Innovation Project for graduate students of Ludong University(IPGS2024-056)。
文摘Water pollution caused by Hg(II)and Ag(I)poses deleterious effects to environmental safety.Adsorption is one of the promising methods to decontaminate aqueous metal ions.Herein,polyhydroxyl-capped poly(amidoamine)(PAMAM)dendrimer/silica composites(G1-OH and G2-OH)were prepared for decontaminating aqueous Hg(II)and Ag(I).The maximum adsorption capacity of G1-OH and G2-OH for Hg(II)are 0.45 and 0.76 mmol/g,while that for Ag(I)are 0.66 and 0.81 mmol/g.The optimum solution pH for the adsorption of Hg(II)and Ag(I)are both 6.The adsorption for Hg(II)and Ag(I)can reach equilibrium at150 and 120 min,respectively.Pseudo-second-order model can be used to describe the adsorption kinetic process and the rate-controlling step is film diffusion process.Adsorption isotherm indicates the adsorption can be promoted by increasing concentration and temperature,and the adsorption process could be described by Langmuir model with chemical mechanism.G1-OH and G2-OH exhibit excellent adsorption selectivity and they can 100%adsorb Hg(II)or Ag(I)with the coexisting of Fe(III),Co(II),Cu(II)or Ni(II).Adsorption mechanism confirms C-N,OH and CONH groups play critical role for the adsorption of the two ions.The work may provide efficient adsorbents for the decontamination of aqueous Hg(II)and Ag(I)with practical value.
文摘An azyl group of ethylene diamine was protected by N-tert-butoxycarbonyl.The remaining azyl group then successively reacted with methyl acrylate, ethylene diamine and methyl acrylate again to afford the compound Boc-NH 2-(B-COOCH 3) 4 3 (AB-4).The ester groups and the Boc-end group of 3 were transferred to carboxylate 4 and azyl group 5 via hydrolyzation and deprotection respectively.The fan-shape dendron molecules with 16 exterior groups 6 were obtained by condensation of 4 and 5 in the presence of DCC.The dumbbell-like dendrimer molecules 7 could expediently prepared by coupling the dendrons with two functional groups of hexanedioyl chloride.The paper describes the synthesis procedures,reports the characterization results of FTIR、 1H-NMR、 13C-NMR and MALDI-TOF.Comparing with the PAMAM dendrimers from the divergent method, the synthesized compounds possess accurate structures and few defections.
文摘The curing process of dendritic polymer PAMAM with bis-phenol A epoxy resin was investigated using isothermal differential scanning calorimetry（DSC）,the mechanism of this reaction was autocatalytic.The data of two reaction rate constants k1,k2 and reaction orders m,n were obtained from Kamal equation.The overall reaction order m+n was between 2.07 and 2.29,the apparent activation energies of E1 and E2 were 59.79 kJ/mol and 56.51 kJ/mol, respectively.The reaction entered into a diffusion controlled stage at the conversion of 50%,experimental data and theoretic curve had deviation at this time.The reaction conversion,at which the deviation occurred,decreased with lowering curing temperature.
文摘H 2PtCl 6 was coordinated with the carboxyl-terminated G4.5PAMAM dendrimer molecules (PAMAMC) in aqueous solution,followed by reduction using NaBH 4 as reducer,and formed Pt-PAMAMC hybrid nano-particles.The stable multilayer films were obtained by fabricating diazo resin(DR) with these hybrid nanoparticles (Pt-PAMAMC) and PAMAMC,respectively.The films were subsequently irradiated under UV-light.It was found that the films from Pt-PAMAMC as polyanions exhibit stable frictional responses under the applied load,and the lubricative property of the films from Pt-PAMAMC hybrid nanoparticles is obviously superior to that of the films from dendrimer without platinum inside.
文摘Well-dispersed CdS quantum dots (QDs) with narrow size-distribution were prepared using generation 4.5 ester-terminated PAMAM dendrimers as inner-templates. The average diameter of CdS QDs was 1.5 nm and the photoluminescence was purple. The room temperature photoluminescence quantum yield (RT-PQY) was 0.015. The diameter of CdS QDs increased with the increase of n / nPAMAM, also the color of photoluminescence was tunable and could be changed from purple to blue.
