Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The compos...Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.展开更多
Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform. Thi...Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform. This process was quantified by UV-Vis spectra. A possible mechanism was put forward based on the formation of amphiphilic aggregates.展开更多
The aromatic hyperbranched poly（ester amines）（AHPEAs） were successfully synthesized via the mild condensation of N-4-cyanobenzyl diethanolamine hydrogenchloride as an AB2 monomer in concentrated HCI. The polymeriz...The aromatic hyperbranched poly（ester amines）（AHPEAs） were successfully synthesized via the mild condensation of N-4-cyanobenzyl diethanolamine hydrogenchloride as an AB2 monomer in concentrated HCI. The polymerization was monitored by FTIR to suppose the reasonable reaction mechanism. The degree of branching was determined to be 0.55 by 1H NMR with an increased conversion of up to 96%. The glass transition temperature was measured by differential scanning calorimetry to range from -19 to 15℃ The molecular weights and polydispersities were investigated by gel permeation chromatography.展开更多
Crosslinked film of hyperbranched poly（amine-ester） （HPAE） was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde （GA）. Atom force microscope （AFM） and scanning electron microscope （SEM...Crosslinked film of hyperbranched poly（amine-ester） （HPAE） was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde （GA）. Atom force microscope （AFM） and scanning electron microscope （SEM） reveals that they have smooth surfaces, dense and homogenous matrices. It was found that the water static contact angle is smaller than 41.7°, the tensile strength is higher than 8.9 MPa, the elongation at break is higher than 5.1%, the swelling degree is higher than 42% in water, and the Bovine hemoglobin （Hb） adsorption is relatively low. These results indicate that the crosslinked HPAE films might have some potential applications in many areas.展开更多
Five secondary amine terminated poly（ester-amine）s （defined as PEA） with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate （PDDA） and 1,1,1-t...Five secondary amine terminated poly（ester-amine）s （defined as PEA） with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate （PDDA） and 1,1,1-trimethylolpropane triacrylate （TMPTA） at a constant secondary amine/acrylate group ratio of 1.5/1 and at different PDDA/TMPTA molar ratios. Both IR and ^1H-NMR spectra indicated that all acrylate groups were consumed in the reaction, based on which the structural parameters were calculated from the ^1H-NMR spectra. With decreasing PDDA/TMPTA ratio, the content of secondary amine, degree of branching, molecular weight, Tg and Td increased accordingly. These polymers were further used as both crosslinkers and flexibilizers for a linear epoxy resin E51 to form cured films under ambient condition. The gel content, relative hardness and Tg of the resulting films increased as PEA molecules changed from linear to highly branching structures. Due to the flexibility of PEA molecules, all the films possessed excellent mechanical performance.展开更多
Three secondary amine terminated hyperbranched poly（ester-amine）s （defined as HPEA1, HPEA2 and HPEA3） were synthesized from piperazine （A2） and trimethylolpropane triacrylate （TMPTA, B3） at their molar ratios ...Three secondary amine terminated hyperbranched poly（ester-amine）s （defined as HPEA1, HPEA2 and HPEA3） were synthesized from piperazine （A2） and trimethylolpropane triacrylate （TMPTA, B3） at their molar ratios of 2.5：1, 2.25：1 and 2.0：1, respectively. The polymers were analyzed by 1H NMR, GPC, DSC and TGA. The results indicated that the ratio of secondary amine to tertiary amine and the content of secondary amine decreased, while the molecular weight, molecular weight distribution and glass transition temperature （Tg） increased from HPEA1 to HPEA3. Due to their reactive terminal groups and flexible chains, these polymers further reacted with an epoxy resin （E51） to form cured films under ambient conditions. With increasing the ratio between secondary amine groups and epoxy groups from 1：2 to 2：1, the gel content, film hardness and onset decomposing temperature of the cured samples increased. The good film performances should make the polymers as the components of non-solvent coating materials.展开更多
Hyperbranched poly(amine-ester) (HBPAE) was synthesized via pseudo-one-step process between trimethylolpropane as a core molecule and N, N-diethylol-3-amine methylpropionate as the AB2 branched monomer. The prepared p...Hyperbranched poly(amine-ester) (HBPAE) was synthesized via pseudo-one-step process between trimethylolpropane as a core molecule and N, N-diethylol-3-amine methylpropionate as the AB2 branched monomer. The prepared polymer was analyzed by IR, GPC, 1H-NMR and thermal analysis (TGA and DSC). The performance of the polymer in cement was tested by measuring the effect of 1, 3 and 5 wt% of HBPAE solutions on the properties of Ordinary Portland Cement. Water of consistency, setting times, bulk density, apparent porosity, compressive strength and combined water content of the polymer/cement pastes were studied. The results showed that water of consistency and apparent porosity decreased while setting times, compressive strength, combined water and bulk density increased with the polymer addition.展开更多
Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, c...Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, cadaverine, spermidine and spermine cause allergic symptoms. We developed simple method for measurement of polyamine as indicator of food decomposition with a fluorometer by using 4-(1-Pyrene)butyric acid N-hydroxysuccinimide ester (PSE). PSE reacts with primary and secondary amino moieties of polyamines and produces the intramolecular excimer fluorescence. Excimer fluorescence with broad peak at around 470 nm was clearly detected in linear type biogenic amines such as putrescine, cadaverine, spermidine and spermine at 10 mM. However neither histamine nor trimethylamine altered the fluorescence. Decomposed sardine and mackerel by improper storage showed stronger intensity than fresh ones. Comparing with OPA-method, PSE method was useful for screening biogenic amines present in food, esp. fish since the analysis was simple after one-step purification procedure. An inexpensive system which can rapidly detect biogenic amines from food is necessary in a medium and small-sized food business. The technique using excimer has potential to realize the high through-put screening system for evaluation of food freshness and is expected to bring the public interests such as food security and safety of consumer.展开更多
Peptide bond formation has drawn more and more attention due to its importance in medicinal chemistry and drug discovery.Using active esters to construct peptide bonds is an indispensable strategy in this field.We her...Peptide bond formation has drawn more and more attention due to its importance in medicinal chemistry and drug discovery.Using active esters to construct peptide bonds is an indispensable strategy in this field.We herein report a fast and efficient amination reaction to synthesize peptides from catechol diesters.Catechol monoesters are good active esters in peptide synthesis due to the anchimeric assistance effect.In previously reported work,the amination reaction was inactivated if the 2-hydroxyl group in the catechol esters was functionalized.However,we found an unusual acceleration of the amination reactivity when the 2-hydroxyl group was functionalized as an ester group.The reaction can be complete in 2−3 min in some cases.This acceleration was found through experimental studies to not result from the anchimeric assistance effect.We proposed aπ*−π*interaction pathway between the two proximal ester groups.Some computational studies were made to support this assumption.展开更多
Two novel amphiphilic poly(ester amine) dendrimers were synthesized and characterized by 1H NMR, 13 C NMR and IR spectra. Their properties of Langmuir film were investigated at the air/water interface....Two novel amphiphilic poly(ester amine) dendrimers were synthesized and characterized by 1H NMR, 13 C NMR and IR spectra. Their properties of Langmuir film were investigated at the air/water interface. The relationship between the surface pressure and area isotherms of the dendrimers was found to be dependent on the nature of subphases. Interaction between HgCl 2 and the dendrimers was observed, indicating that the amphiphilic dendrimers could act as a sensor for Hg 2+ .展开更多
The air oxidation of acrylic esters with or without AIBN has been discussed in some studies. But the air oxidation in the presence of amine as promoter has not been previously reported. It is well known that amine was...The air oxidation of acrylic esters with or without AIBN has been discussed in some studies. But the air oxidation in the presence of amine as promoter has not been previously reported. It is well known that amine was considered as an an-展开更多
Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their st...Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their structures were characterized by 1H NMR,GPC and DSC analysis.The multi peaks within δ 4.04～4.18 (RCH 2OCOR′) in the 1H NMR spectra were analyzed and the peaks at δ 4.15, δ 4 06～4 07 and δ 4.04 can be assigned to terminal ( T ),linear ( L ) and dendritic units ( D ),respectively.Based on 1H NMR spectra,the degree of branching ( DB) for these polymers were calculated by using both the Fréchet method and the Frey method.With the molar ratio between pizine and TMPTA increased to 1/1,the terminate units decreased,both of the dendritic and linear units increased,while M n and M w/ M n became large and the T g value became high,accordingly.Moreover,cured films were obtained through UV radiation of the polymers.The gel contents for the films decreased with increasing the molar ratio between pizine and TMPTA,which may account for the changes of their mechanical properties.展开更多
基金Sponsored by the Ministerial Level Advanced Research Foundation (120701BQ0126)
文摘Nano-SiO2 was modified using silane coupling agent （KH-550） and hyperbranched poly（amine-ester） respectively, and Poly（vinyl chloride） （PVC）/modified nano-SiO2 composites were made by melt-blending. The composites＇ structures andmechanical properties were characterized by transmission electron microscopy（TEM）, sanning electronic microscopy（SEM） and electronic universal testing machine. The results. show that nano-SiO2 grafted by hyperbranched poly （amine-ester） increases obviously in dispersion in PVC matrix, and mechanical properties of PVC are effectively improved. Moreover, it was found that mechanical properties of PVC/nano-SiO2 composites reach the best when weight percent of nano-SiO2 in PVC matrix is 1%. Compared with crude PVC, the tensile strength of hyperbranched poly （amine-ester） grafted nano-SiO2/ PVC composite increases by 24.68 % and its break elongation, flexural strength and impact strength increase by 15.73%, 4.07% and 1 841.84%, respectively. Moreover, the processing of the composites is improved.
文摘Hydrophilic hyperbranched poly(ester-amine) (HPEA) synthesized from diethanolamine and methyl acrylate was used as phase transfer agent for the first time to transfer methyl orange (MO) from water into chloroform. This process was quantified by UV-Vis spectra. A possible mechanism was put forward based on the formation of amphiphilic aggregates.
基金Supported by the National Natural Science Foundation of China(No.50633010)
文摘The aromatic hyperbranched poly（ester amines）（AHPEAs） were successfully synthesized via the mild condensation of N-4-cyanobenzyl diethanolamine hydrogenchloride as an AB2 monomer in concentrated HCI. The polymerization was monitored by FTIR to suppose the reasonable reaction mechanism. The degree of branching was determined to be 0.55 by 1H NMR with an increased conversion of up to 96%. The glass transition temperature was measured by differential scanning calorimetry to range from -19 to 15℃ The molecular weights and polydispersities were investigated by gel permeation chromatography.
基金This work was supported by the National Natural Science Foundation of China (No. 50103010)the "973" Program (No. 2003. CB615705)
文摘Crosslinked film of hyperbranched poly（amine-ester） （HPAE） was prepared by crosslinking its terminal hydroxyl groups with glutaraldehyde （GA）. Atom force microscope （AFM） and scanning electron microscope （SEM） reveals that they have smooth surfaces, dense and homogenous matrices. It was found that the water static contact angle is smaller than 41.7°, the tensile strength is higher than 8.9 MPa, the elongation at break is higher than 5.1%, the swelling degree is higher than 42% in water, and the Bovine hemoglobin （Hb） adsorption is relatively low. These results indicate that the crosslinked HPAE films might have some potential applications in many areas.
基金The work was financially supported by the National Science Foundation of China(Nos.20204005,50233030).
文摘Five secondary amine terminated poly（ester-amine）s （defined as PEA） with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate （PDDA） and 1,1,1-trimethylolpropane triacrylate （TMPTA） at a constant secondary amine/acrylate group ratio of 1.5/1 and at different PDDA/TMPTA molar ratios. Both IR and ^1H-NMR spectra indicated that all acrylate groups were consumed in the reaction, based on which the structural parameters were calculated from the ^1H-NMR spectra. With decreasing PDDA/TMPTA ratio, the content of secondary amine, degree of branching, molecular weight, Tg and Td increased accordingly. These polymers were further used as both crosslinkers and flexibilizers for a linear epoxy resin E51 to form cured films under ambient condition. The gel content, relative hardness and Tg of the resulting films increased as PEA molecules changed from linear to highly branching structures. Due to the flexibility of PEA molecules, all the films possessed excellent mechanical performance.
文摘Three secondary amine terminated hyperbranched poly（ester-amine）s （defined as HPEA1, HPEA2 and HPEA3） were synthesized from piperazine （A2） and trimethylolpropane triacrylate （TMPTA, B3） at their molar ratios of 2.5：1, 2.25：1 and 2.0：1, respectively. The polymers were analyzed by 1H NMR, GPC, DSC and TGA. The results indicated that the ratio of secondary amine to tertiary amine and the content of secondary amine decreased, while the molecular weight, molecular weight distribution and glass transition temperature （Tg） increased from HPEA1 to HPEA3. Due to their reactive terminal groups and flexible chains, these polymers further reacted with an epoxy resin （E51） to form cured films under ambient conditions. With increasing the ratio between secondary amine groups and epoxy groups from 1：2 to 2：1, the gel content, film hardness and onset decomposing temperature of the cured samples increased. The good film performances should make the polymers as the components of non-solvent coating materials.
文摘Hyperbranched poly(amine-ester) (HBPAE) was synthesized via pseudo-one-step process between trimethylolpropane as a core molecule and N, N-diethylol-3-amine methylpropionate as the AB2 branched monomer. The prepared polymer was analyzed by IR, GPC, 1H-NMR and thermal analysis (TGA and DSC). The performance of the polymer in cement was tested by measuring the effect of 1, 3 and 5 wt% of HBPAE solutions on the properties of Ordinary Portland Cement. Water of consistency, setting times, bulk density, apparent porosity, compressive strength and combined water content of the polymer/cement pastes were studied. The results showed that water of consistency and apparent porosity decreased while setting times, compressive strength, combined water and bulk density increased with the polymer addition.
文摘Biogenic amines are known to have various biological functions such as not only neurotransmitter and cell proliferation but also food poisoning. Bacterially-decomposed amines such as histamine, agmatine, putrescine, cadaverine, spermidine and spermine cause allergic symptoms. We developed simple method for measurement of polyamine as indicator of food decomposition with a fluorometer by using 4-(1-Pyrene)butyric acid N-hydroxysuccinimide ester (PSE). PSE reacts with primary and secondary amino moieties of polyamines and produces the intramolecular excimer fluorescence. Excimer fluorescence with broad peak at around 470 nm was clearly detected in linear type biogenic amines such as putrescine, cadaverine, spermidine and spermine at 10 mM. However neither histamine nor trimethylamine altered the fluorescence. Decomposed sardine and mackerel by improper storage showed stronger intensity than fresh ones. Comparing with OPA-method, PSE method was useful for screening biogenic amines present in food, esp. fish since the analysis was simple after one-step purification procedure. An inexpensive system which can rapidly detect biogenic amines from food is necessary in a medium and small-sized food business. The technique using excimer has potential to realize the high through-put screening system for evaluation of food freshness and is expected to bring the public interests such as food security and safety of consumer.
基金supported by Grant-in-Aid for Scientific Research from the New Energy and Industrial Technology Development Organization(NEDO)project(JPNP14004)and The Naito Foundation.
文摘Peptide bond formation has drawn more and more attention due to its importance in medicinal chemistry and drug discovery.Using active esters to construct peptide bonds is an indispensable strategy in this field.We herein report a fast and efficient amination reaction to synthesize peptides from catechol diesters.Catechol monoesters are good active esters in peptide synthesis due to the anchimeric assistance effect.In previously reported work,the amination reaction was inactivated if the 2-hydroxyl group in the catechol esters was functionalized.However,we found an unusual acceleration of the amination reactivity when the 2-hydroxyl group was functionalized as an ester group.The reaction can be complete in 2−3 min in some cases.This acceleration was found through experimental studies to not result from the anchimeric assistance effect.We proposed aπ*−π*interaction pathway between the two proximal ester groups.Some computational studies were made to support this assumption.
基金theNationalNaturalScienceFoundationofChina (No .5 0 2 3 3 0 3 0 )theBasicResearchFoundationofTsinghuaUniversity (No .2 0 0 2 0 3 0 )
文摘Two novel amphiphilic poly(ester amine) dendrimers were synthesized and characterized by 1H NMR, 13 C NMR and IR spectra. Their properties of Langmuir film were investigated at the air/water interface. The relationship between the surface pressure and area isotherms of the dendrimers was found to be dependent on the nature of subphases. Interaction between HgCl 2 and the dendrimers was observed, indicating that the amphiphilic dendrimers could act as a sensor for Hg 2+ .
文摘The air oxidation of acrylic esters with or without AIBN has been discussed in some studies. But the air oxidation in the presence of amine as promoter has not been previously reported. It is well known that amine was considered as an an-
文摘Aliphatic hyperbranched poly(ester amine)s with terminal acrylate groups were synthesized by Michael addition reaction between pizine and trimethylol propanetriacrylate (TMPTA) under various molar ratios, and their structures were characterized by 1H NMR,GPC and DSC analysis.The multi peaks within δ 4.04～4.18 (RCH 2OCOR′) in the 1H NMR spectra were analyzed and the peaks at δ 4.15, δ 4 06～4 07 and δ 4.04 can be assigned to terminal ( T ),linear ( L ) and dendritic units ( D ),respectively.Based on 1H NMR spectra,the degree of branching ( DB) for these polymers were calculated by using both the Fréchet method and the Frey method.With the molar ratio between pizine and TMPTA increased to 1/1,the terminate units decreased,both of the dendritic and linear units increased,while M n and M w/ M n became large and the T g value became high,accordingly.Moreover,cured films were obtained through UV radiation of the polymers.The gel contents for the films decreased with increasing the molar ratio between pizine and TMPTA,which may account for the changes of their mechanical properties.
