Structural changes in poly(ethylene terephthalate) induced by cryomilling and ambimilling

2006 ◽  
Vol 44 (6) ◽  
pp. 986-993 ◽  
Author(s):  
Yan-guo Zhu ◽  
Zhi-Qiang Li ◽  
Di Zhang ◽  
Toshio Tanimoto
Keyword(s):  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

scholarly journals Comparative Study of Structural Changes of Polylactide and Poly(ethylene terephthalate) in the Presence of Trichoderma viride

2021 ◽  
Vol 22 (7) ◽  
pp. 3491
Author(s):  
Grażyna B. Dąbrowska ◽  
Zuzanna Garstecka ◽  
Ewa Olewnik-Kruszkowska ◽  
Grażyna Szczepańska ◽  
Maciej Ostrowski ◽  
...  
Keyword(s):  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Molecular Mechanisms ◽  
Blot Hybridization ◽  
Trichoderma Viride ◽  
Cost Effective ◽  
Plastic Pollution ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Plastic pollution is one of the crucial global challenges nowadays, and biodegradation is a promising approach to manage plastic waste in an environment-friendly and cost-effective way. In this study we identified the strain of fungus Trichoderma viride GZ1, which was characterized by particularly high pectinolytic activity. Using differential scanning calorimetry, Fourier-transform infrared spectroscopy techniques, and viscosity measurements we showed that three-month incubation of polylactide and polyethylene terephthalate in the presence of the fungus lead to significant changes of the surface of polylactide. Further, to gain insight into molecular mechanisms underneath the biodegradation process, western blot hybridization was used to show that in the presence of poly(ethylene terephthalate) (PET) in laboratory conditions the fungus produced hydrophobin proteins. The mycelium adhered to the plastic surface, which was confirmed by scanning electron microscopy, possibly due to the presence of hydrophobins. Further, using atomic force microscopy we demonstrated for the first time the formation of hydrophobin film on the surface of aliphatic polylactide (PLA) and PET by T. viride GZ1. This is the first stage of research that will be continued under environmental conditions, potentially leading to a practical application.

Amplitude Spectrum Approach in Dynamic FT-IR Spectroscopy of Uniaxially Oriented Poly(Ethylene Terephthalate) Films. Part I: Draw Ratio Dependence

1997 ◽  
Vol 51 (3) ◽  
pp. 346-349 ◽  
Author(s):  
Masashi Sonoyama ◽  
Kunihiro Shoda ◽  
Gen Katagiri ◽  
Hideyuki Ishida
Keyword(s):  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Amplitude Spectrum ◽  
Data Manipulation ◽  
Poly Ethylene Terephthalate ◽  
Ft Ir ◽  
Poly Ethylene ◽  
Mechanical Stretching ◽  
Methylene Group ◽  
Ft Ir Spectroscopy

A method of data manipulation using the dynamic magnitude spectrum and the static absorbance spectrum is applied to uniaxially drawn poly(ethylene terephthalate) films with five different draw ratios for the evaluation of the amplitude of dynamic structural changes under a sinusoidal strain at the level of a functional group. This analysis revealed that, in the drawn film, the skeletal structures, such as the C–O bond in the ethylene glycol unit and the phenyl ring, are susceptible to deformation by mechanical stretching, while the dynamic structural changes around the methylene group are small. It was assumed that the backbone of the polymer is responsible for the change of the mechanical properties induced by the drawing of the film.

scholarly journals Fatty food, or fatty food simulants and PET packaging interactions: study with DETA

2013 ◽  
Vol 32 (1) ◽  
pp. 283
Author(s):  
Aleksandra Porjazoska Kujundziski ◽  
Toma Grchev ◽  
Chamovska Chamovska ◽  
Maja Cvetkovska
Keyword(s):  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Polymer Structure ◽  
Packaging Material ◽  
Food Simulants ◽  
Poly Ethylene Terephthalate ◽  
Fatty Food ◽  
Poly Ethylene ◽  
Polar Polymer

Dynamic electrical thermal analysis (DETA) is considered as a valuable technique for determination of polar polymer structure or changes in the polymer structure as a result of different treatments. Therefore, with this study, we wanted to check whether this technique can indicate structural changes in the PET packaging material in contact with specific media. Positive response give the opportunity to use the study of PET packaging dielectric properties after a programmed contact with some medium, to indicate possible interactions between packaging material and the medium, or packaging and foodstuff. It is also known that official simulants may have some drawbacks as migration of the potential contaminants depends on the interaction between the simulant and packaging and thus the values for measured migration could be exaggerated or too low.The possibility of DETA to indicate structural changes in the packaging material give also the opportunity to adjust the aggressiveness of some medium to the packaging, that is, some solvent, or mixture of solvents with different polarity, and thus to choose the most appropriate simulant – medium which will behave in the same way as the foodstuff.In this study we have chosen several conventional fatty food simulants: olive oil, isooctane, 3% acetic acid, and ethanol, and using the DET analysis we compared the influence of these media and the real foodstuff (mayonnaise) on the structure of poly(ethylene terephthalate) (PET) food containers.

scholarly journals Biodegradation of Poly(Ethylene Terephthalate) Microplastics by Baceterial Communities From Activated Sludge

2021 ◽  
Author(s):  
Patricia Torena
Keyword(s):  
Activated Sludge ◽  
Bacterial Communities ◽  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Bacterial Strains ◽  
Clear Zone ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Degrading Bacteria ◽  
Poly Ethylene

The emerging accumulation of microplastics (MPs) within global waters and the risks they pose to both humans and aquatic species are of increasing concern, yet suitable technologies to remove MPs are lacking. In this study, bacteria with potential to degrade MPs were isolated from activated sludge as promising biocatalysts for the removal of MPs in water. The bacterial communities in activated sludge were first screened for their potential to degrade thermallytreated MPs from PET. The consortium exhibited growth on a mineral medium with PET MPs as the sole carbon and energy source, indicating the presence of degrading bacteria. To further assess its biodegradability potential, the consortium was put through a CO2 evolution test where the degradation of MPs was monitored through measuring the CO2 evolved. The test was carried out in an experimental device that was engineered and constructed according to ISO 14852. The biodegradation extent was further validated through assessment of morphological and structural changes on the MPs by means of scanning electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy analyses. Upon incubation, the consortium degraded 17 % of PET MPs. Three bacterial strains within the consortium were isolated and identified as Lysinibacillus macroides RW13-2, Bacillus cereus SEHD031MH and Agromyces mediolanus PNP3. The latter two thrived individually with PET while only B. cereus showed enzymatic activity during a clear-zone test. The examined bacterial strains possess a promising PETdegrading activity that can be further investigated and applied to the elimination of MPs in water/wastewater through innovative and effective technologies

scholarly journals Assessment of the PETase Conformational Changes Induced by Poly(ethylene terephthalate) Binding

2021 ◽  
Author(s):  
Clauber Henrique Costa ◽  
Alberto dos Santos ◽  
Cláudio Nahum Alves ◽  
Sérgio Martí ◽  
Vicente Moliner ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Conformational Changes ◽  
Active Site ◽  
Terephthalic Acid ◽  
Structural Changes ◽  
Ethylene Terephthalate ◽  
Md Simulations ◽  
Poly Ethylene Terephthalate ◽  
Bounded State ◽  
Poly Ethylene

Recently, a bacterium strain of Ideonella sakaiensis was identified with the uncommon ability to degrade the poly(ethylene terephthalate) (PET). The PETase from I. sakaiensis strain 201-F6 catalyzes the hydrolysis of PET converting it to mono(2-hydroxyethyl) terephthalic acid (MHET), bis(2-hydroxyethyl)-TPA (BHET), and terephthalic acid (TPA). Despite the potential of this enzyme for mitigation or elimination of environmental contaminants, one of the limitations of the use of PETase for PET degradation is the fact that it acts only at moderate temperature due to its low thermal stability. Besides, molecular details of the main interaction of PET in the active site of PETase remains unclear. Herein, molecular docking and molecular dynamics (MD) simulations were applied to analyze structural changes of PETase induced by PET binding. Results from the essential dynamics revealed that β1-β2 connecting loop is very flexible. This Loop is located far from the active site of PETase and we suggest that it can be considered for mutagenesis in order to increase the thermal stability of PETase. The free energy landscape (FEL) demonstrates that the main change in the transition between the unbounded to the bounded state is associated with β7-α5 connecting loop, where the catalytic residue Asp206 is located. Overall, the present study provides insights into the molecular binding mechanism of PET into the PETase structure and a computational strategy for mapping flexible regions of this enzyme, which can be useful for the engineering of more efficient enzymes for recycling the plastic polymers using biological systems.

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