Six novel hydrolytically degradable polyesters were synthesized from thiodipropionic acid(TDPA)and five diols by melt polycondensation,and characterized by FT-IR,1H NMR,gel permeation chromatography,differential scann...Six novel hydrolytically degradable polyesters were synthesized from thiodipropionic acid(TDPA)and five diols by melt polycondensation,and characterized by FT-IR,1H NMR,gel permeation chromatography,differential scanning calorimetry and thermogravimetry analysis.The polystyrene-equivalent number-average(Mn)and weight-average molecular weight(Mw)of these polyesters ranged from 4900-11100 Da and 7900-20879 Da,respectively,with PDI values of 1.48-1.98.The melting point varied from 62.3-127.9℃,and the 50%mass-loss temperature ranged between 387-417℃.The degradation of these polyesters was studied in terms of relative weight loss in distilled water at different pH.Weight losses of 14%-26%were obtained at pH 7.0,26%-38%at pH 6.0,and 32%-43%at pH 8.3 over a 20-week period.The ecotoxicity study suggested that safety of the synthesized polyesters for the eisenia foetida.These results indicate that these polyesters have a combination of good thermal and degradability behaviors,which can be tailored through selection of the diol monomers used in the synthesis.展开更多
Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified ...Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified as PEOT-x,where x is the mole fraction of furandicarboxylic acid in the samples,were synthesized by direct esterification.The molecular structure of the copolyesters was characterized by FTIR and 1H NMR spectroscopy.Gel permeation chromatography (GPC),differential scanning calorimetry (DSC),and thermogravimetric analysis (TGA) were used to characterize the molecular weight,molar mass dispersity,glass transition temperature,and thermal stability of the copolyesters,respectively.The mechanical properties of the samples were also investigated.The number-average molecular weight (M_(n)) of the samples varies from 9 700-18 800 g/mol,and molar mass dispersity (■=M_(w)/M_(n)) from 2.15-3.34.The initial decomposition temperature of the copolyesters is in the 332-356 ℃ range,with maximum decomposition rates at 390-410 ℃,while the glass transition temperature (Tg) varies from 0-33 ℃.Mechanical test shows that PEOT-10 has the highest tensile strength,while PEOT-90 has the largest tensile modulus and elongation at break.The experimental results show that these copolyesters can be synthesized with relatively high molecular weights,good thermal stability,and fair mechanical properties,which makes them excellent replacements for commercial polyesters,such as PET,and these properties can be tuned through the relative amounts of biomass monomer 2,5-furandicarboxylic acid used in the reactions.展开更多
A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR...A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR and ^(1)H NMR spectroscopy,gel permeation chromatography(GPC)and differential scanning calorimetry(DSC)analysis.The polydispersity index(PDI=M_(w)/M_(n))of the polyesters ranged from 1.55 to 1.99,the weight-average molecular weight(M_(w))from 1.8×10^(4) to 3.2×10^(4) Da,the melting point from 63 to 123℃,and the highest decomposition temperature observed was 363℃.The influence of the structure of the polymer chain on hydrolytic degradability was investigated with tests performed at three different values of pH.The findings obtained provide useful insight for the molecular design and the synthesis of degradable polyesters.展开更多
基金Funded by the Program (BG20190227001)of High-end Foreign Experts of the State Administration of Foreign Experts Affairs (SAFEA)the Coal Conversion and New Carbon Materials Hubei Key Laboratory at Wuhan University of Science and Technology (WKDM202005)。
文摘Six novel hydrolytically degradable polyesters were synthesized from thiodipropionic acid(TDPA)and five diols by melt polycondensation,and characterized by FT-IR,1H NMR,gel permeation chromatography,differential scanning calorimetry and thermogravimetry analysis.The polystyrene-equivalent number-average(Mn)and weight-average molecular weight(Mw)of these polyesters ranged from 4900-11100 Da and 7900-20879 Da,respectively,with PDI values of 1.48-1.98.The melting point varied from 62.3-127.9℃,and the 50%mass-loss temperature ranged between 387-417℃.The degradation of these polyesters was studied in terms of relative weight loss in distilled water at different pH.Weight losses of 14%-26%were obtained at pH 7.0,26%-38%at pH 6.0,and 32%-43%at pH 8.3 over a 20-week period.The ecotoxicity study suggested that safety of the synthesized polyesters for the eisenia foetida.These results indicate that these polyesters have a combination of good thermal and degradability behaviors,which can be tailored through selection of the diol monomers used in the synthesis.
基金Funded by the Program (BG20190227001) of High-end Foreign Experts of the State Administration of Foreign Experts Affairs (SAFEA)the 2021 Innovative Training Program for College Students in Hubei Province。
文摘Terephthalic acid,2,5-furandicarboxylic acid and 1,8-octanediol were adopted as monomers and antimony trioxide as catalyst,and poly(terephthalic acid-2,5-furandicarboxylic acid-1,8-octanediol) copolyesters identified as PEOT-x,where x is the mole fraction of furandicarboxylic acid in the samples,were synthesized by direct esterification.The molecular structure of the copolyesters was characterized by FTIR and 1H NMR spectroscopy.Gel permeation chromatography (GPC),differential scanning calorimetry (DSC),and thermogravimetric analysis (TGA) were used to characterize the molecular weight,molar mass dispersity,glass transition temperature,and thermal stability of the copolyesters,respectively.The mechanical properties of the samples were also investigated.The number-average molecular weight (M_(n)) of the samples varies from 9 700-18 800 g/mol,and molar mass dispersity (■=M_(w)/M_(n)) from 2.15-3.34.The initial decomposition temperature of the copolyesters is in the 332-356 ℃ range,with maximum decomposition rates at 390-410 ℃,while the glass transition temperature (Tg) varies from 0-33 ℃.Mechanical test shows that PEOT-10 has the highest tensile strength,while PEOT-90 has the largest tensile modulus and elongation at break.The experimental results show that these copolyesters can be synthesized with relatively high molecular weights,good thermal stability,and fair mechanical properties,which makes them excellent replacements for commercial polyesters,such as PET,and these properties can be tuned through the relative amounts of biomass monomer 2,5-furandicarboxylic acid used in the reactions.
基金Funded by the Program(BG20190227001)of High-end Foreign Experts of the State Administration of Foreign Experts Affairs(SAFEA)the Coal Conversion and New Carbon Materials Hubei Key Laboratory in Wuhan University of Science and Technology(WKDM201909)。
文摘A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR and ^(1)H NMR spectroscopy,gel permeation chromatography(GPC)and differential scanning calorimetry(DSC)analysis.The polydispersity index(PDI=M_(w)/M_(n))of the polyesters ranged from 1.55 to 1.99,the weight-average molecular weight(M_(w))from 1.8×10^(4) to 3.2×10^(4) Da,the melting point from 63 to 123℃,and the highest decomposition temperature observed was 363℃.The influence of the structure of the polymer chain on hydrolytic degradability was investigated with tests performed at three different values of pH.The findings obtained provide useful insight for the molecular design and the synthesis of degradable polyesters.
