The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly add...The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly additives,can scavenge free radicals to enhance polymer durability.However,rough choices have resulted in wastage of resources and environmental pressure.Based on the application of plastic films as the background for use,this study systematically evaluates application effects of five HALSs.The films underwent accelerated aging for various durations and were further investigated by a combination of experiments and molecular simulation.Results showed that all HALSs mitigated PBAT light aging,with Chimassorb-944(UV-944)and Tinuvin-770(UV-770)performing the best for real applications.Quantum chemical calculation results showed that UV-944 had stronger anti migration ability.After 300 h of aging,films with UV-944 and UV-770 retained superior tensile strength and elongation at break in the transverse direction compared to neat PBAT films.Polymeric HALSs provided better long-term stability than small-molecule ones.Further spectra analysis indicated that stronger C―O bonds in HALS/PBAT composites correlated with improved photostability.This study offers valuable insights into improving weather resistance of PBAT biodegradable films and optimizing the real application of HALSs.展开更多
The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutio...The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutions containing KCl (0.1 M). The relaxation time is longer when the applied voltages are between-0.4 V and-0.8 V(vs. SCE) where the Raman effect also shows greater surface enhancement. Also observed was that for the piperidine case the relaxation time reaches its maximum at the more negative applied voltage. The origin of the relaxation is attributed mainly to the desorp- tion process of the pyrazine. pyridine and piperidine molecules off the roughened Ag electrode. An. electrostatic model was also proposed for the interpretation of these experimental observations.展开更多
基金supported by the Key Research and Development Task Project of Xinjiang Uygur Autonomous Region(No.2022B02033)the National Natural Science Foundation of China(Nos.42211530566 and 42311530066)+2 种基金the NSFC-FNRS Joint Program BIOAGRIFILM(No.FNRS PINT-BILATM 2022)the Science and Technology Project of Bijie Tobacco Company of Guizhou Province(No.2022520500240192)the Agricultural Science and Technology Innovation Program(ASTIP)。
文摘The application of poly(butylene adipate-co-terephthalate)(PBAT)biodegradable plastics has long been constrained by insufficient light aging resistance.Hindered amine light stabilizers(HALSs),known as eco-friendly additives,can scavenge free radicals to enhance polymer durability.However,rough choices have resulted in wastage of resources and environmental pressure.Based on the application of plastic films as the background for use,this study systematically evaluates application effects of five HALSs.The films underwent accelerated aging for various durations and were further investigated by a combination of experiments and molecular simulation.Results showed that all HALSs mitigated PBAT light aging,with Chimassorb-944(UV-944)and Tinuvin-770(UV-770)performing the best for real applications.Quantum chemical calculation results showed that UV-944 had stronger anti migration ability.After 300 h of aging,films with UV-944 and UV-770 retained superior tensile strength and elongation at break in the transverse direction compared to neat PBAT films.Polymeric HALSs provided better long-term stability than small-molecule ones.Further spectra analysis indicated that stronger C―O bonds in HALS/PBAT composites correlated with improved photostability.This study offers valuable insights into improving weather resistance of PBAT biodegradable films and optimizing the real application of HALSs.
基金This work was supported by the National Natural Science Foundation of ChinaNational Laboratory for Structural Chemistry of Dynamical and Stable Species.
文摘The light beating technique (intensity correlation algorithm) was employed to analyze the Rayleigh scattering from the roughened Ag electrode in very dilute (10^(-4)M) pyrazine, pyridine and piperidine aqueous solutions containing KCl (0.1 M). The relaxation time is longer when the applied voltages are between-0.4 V and-0.8 V(vs. SCE) where the Raman effect also shows greater surface enhancement. Also observed was that for the piperidine case the relaxation time reaches its maximum at the more negative applied voltage. The origin of the relaxation is attributed mainly to the desorp- tion process of the pyrazine. pyridine and piperidine molecules off the roughened Ag electrode. An. electrostatic model was also proposed for the interpretation of these experimental observations.
