The synthesis route was investigated and optimized for the preparation of iminodiacetic acid-polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phase systems. IDA-PEG was synt...The synthesis route was investigated and optimized for the preparation of iminodiacetic acid-polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phase systems. IDA-PEG was synthesized from PEG in two steps by the reaction of iminodiacetic acid with a monosubstituted derivative of epichlorohydrin-activated PEG. The Cu2+ content combined with IDA-PEG was determined by atomic absorption spectrometry as 0.5 mol·mol^-1 (PEG). Furthermore, the affinity partitioning behavior of lactate dehydrogenase in polyethylene glycol/hydroxypropyl starch aqueous two-phase systems was studied to clarify the affinity effect of the Cu(Ⅱ)-IDA-PEG.展开更多
Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated in...Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.展开更多
To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly（lactic acid-co-glycol terephthalate） （PETA）, was synthesized from three monomers of lactic acid...To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly（lactic acid-co-glycol terephthalate） （PETA）, was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, ^1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the Tins and Tas of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.展开更多
It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusio...It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusion blending.The thermal,crystalline and mechanical properties of blends were investigated with TGA,DSC,WAXD and universal testing machine.The degradation of the blends in soil,acid and alkaline buffer solutions was assessed,respectively.It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process.The starting decomposition temperature lowered from 412.1 ℃ of pure PET to 330.4 ℃ at 50% PLA content,tensile and bending strength of blends gradually decreased with the PLA content increasing,while the degradation rate improved.Alkaline environment was most beneficial for blends to degrade.The degradation mechanism was discussed.展开更多
基金Supported by the National Natural Science Foundation of China(No.29736180).
文摘The synthesis route was investigated and optimized for the preparation of iminodiacetic acid-polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phase systems. IDA-PEG was synthesized from PEG in two steps by the reaction of iminodiacetic acid with a monosubstituted derivative of epichlorohydrin-activated PEG. The Cu2+ content combined with IDA-PEG was determined by atomic absorption spectrometry as 0.5 mol·mol^-1 (PEG). Furthermore, the affinity partitioning behavior of lactate dehydrogenase in polyethylene glycol/hydroxypropyl starch aqueous two-phase systems was studied to clarify the affinity effect of the Cu(Ⅱ)-IDA-PEG.
文摘Gamma-ray radiation has always been a convenient and effective way to modify the inter- facial properties in polymer blends. In this work, a small amount of trimethylolpropane triacrylate （TMPTA） was incorporated into poly（ethylene terephthalate） （PET）/random terpolymer elastomer （ST2000） blends by melt-blending. The existence of TMPTA would induce the crosslinking of PET and ST2000 molecular chains at high temperatures of blend- ing, resulting in the improvement in the impact strength but the loss in the tensile strength. When the PET/ST2000 blends were irradiated by gamma-ray radiation, the integrated me- chanical properties could be enhanced significantly at a high absorbed dose. The irradiated sample at a dose of 100 kGy even couldn＇t be broken under the impact test load, and at the same time, has nearly no loss of tensile strength. Based on the analysis of the impact- fractured surface morphologies of the blends, it can be concluded that gamma-ray radiation at high absorbed dose can further in situ enhance the interfacial adhesion by promoting the crosslinking reactions of TMPTA and polymer chains. As a result, the toughness and strength of PET/ST2000 blend could be dramatically improved. This work provides a facial and practical way to the fabrication of polymer blends with high toughness and strength.
文摘To obtain a kind of biodegradable polymer material with satisfactory properties, a new biodegradable copolyester poly（lactic acid-co-glycol terephthalate） （PETA）, was synthesized from three monomers of lactic acid, glycol and terephthalic acid. The resulting copolyesters, PETA, were characterized by FT-IR, ^1H-NMR, DSC, TGA and by the ways of weight loss rate to characterize their biodegradability. The findings in this work indicated that, the Tins and Tas of copolyesters PETA increased with increasing contents of the terephthalic acid units. From the biodegradation tests in natural soil, boiling water, acid buffer solution and alkali buffer solution, it was shown that the biodegradability of copolyesters PETA decreased with increasing contents of the terephthalic acid units.
文摘It is difficult for polyethylene terephthalate （PET） to degrade,which caused severe pollution.In this work,polylactic acid （PLA） was introduced to improve the degradation of PET.PET/PLA was synthesized by extrusion blending.The thermal,crystalline and mechanical properties of blends were investigated with TGA,DSC,WAXD and universal testing machine.The degradation of the blends in soil,acid and alkaline buffer solutions was assessed,respectively.It was found that the introduction of a little PLA promoted crystallization of PET during injection molding process.The starting decomposition temperature lowered from 412.1 ℃ of pure PET to 330.4 ℃ at 50% PLA content,tensile and bending strength of blends gradually decreased with the PLA content increasing,while the degradation rate improved.Alkaline environment was most beneficial for blends to degrade.The degradation mechanism was discussed.
