scholarly journals Structure evolution and mechanical behavior of poly(ethylene terephthalate) fibers drawn at different number of drawing stages

2012 ◽  
Vol 18 (2) ◽  
pp. 233-243 ◽  
Author(s):  
Aminoddin Haji ◽  
Semnani Rahbar

In this work, the structure, mechanical and thermal properties of PET fiber obtained by hot multi-stage drawing have been investigated in terms of their dependence on the number of drawing steps at an equivalent total draw ratio. Differential scanning calorimetry, birefringence, wide-angle x-ray diffraction, FTIR spectroscopy, tensile properties, and taut-tie molecules were used to characterize the fine structure and physical properties of the fibers. Results have been explained in terms of a higher drawing residence time at an equivalent drawing speed. For single stage drawn fiber, a high tensile strength is obtained, whereas a high initial modulus is obtained for fiber drawn at three-stage drawing. According to the results, an important finding is that three-stage drawing process has the potential to produce high-modulus fibers. The enhanced fraction of taut-tie molecules is found in three-stage drawn fiber, which is believed to be one of the important factors leading to the high modulus achieved in fibers drawn in hot multistage.

1992 ◽  
Vol 36 ◽  
pp. 379-386
Author(s):  
T. Blanton ◽  
R. Seyler

The effect of dimethyl-5-sodiosulfoisophthalate, SIP, on poly(ethylene terephthalate), PET, crystallization has been studied using in situ high-temperature x-ray diffraction, HTXRD. At low levels of SIP modification, PET-like crystallinity was observed. At high SIP levels, clustering of polyester ionomers was observed and crystallization was significantly suppressed. The HTXRD data along with differential scanning calorimetry, DSC, and small angle x-ray scattering, SAXS, indicate that the change from bulk crystallization to bulk ionomer formation occurred when 8-12 mol% of the diester linkages contained SIP.


Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5783
Author(s):  
Tomoki Tokuda ◽  
Ryo Tsuruda ◽  
Takuya Hara ◽  
Haruki Kobayashi ◽  
Katsufumi Tanaka ◽  
...  

Melt-electrospinning is an eco-friendly method for producing ultra-fine fibers without using any solvent. We prepared webs of poly(ethylene terephthalate) (PET) through melt-electrospinning using CO2 laser irradiation for heating. The PET webs comprised ultra-fine fibers of uniform diameter (average fiber diameter = 1.66 μm, coefficient of variation = 19%). The co-existence of fibers with high and low molecular orientation was confirmed through birefringence measurements. Although the level of high orientation corresponded to that of commercial highly oriented yarn, crystalline diffraction was not observed in the wide-angle X-ray diffraction (WAXD) analysis of the webs. The crystallinity of the webs was estimated using differential scanning calorimetry (DSC). The fibers with higher birefringence did not exhibit any cold crystallization peak. After annealing the web at 116 °C for 5 min, a further increase in the birefringence of the fibers with higher orientation was observed. The WAXD results revealed that the annealed webs showed crystalline diffraction peaks with the orientation of the c-axis along the fiber axis. In summary, the formation of fibers with a unique non-crystalline structure with extremely high orientation was confirmed.


2012 ◽  
Vol 560-561 ◽  
pp. 614-619 ◽  
Author(s):  
Yun Wang ◽  
Lin Gao ◽  
Xiao Wang ◽  
Yu Mei Zhang ◽  
Shi Yan Chen

To characterize the performance of Poly(ethylene terephthalate) (PET) fibers of high modulus and low shrinkage (HMLS), static and dynamic mechanical test, DSC, DMA and sonic orientation experiments were carried out. The results indicated that tenacity, initial modulus, Lase-5 decreased and ultimate elongation increased with heat treatment temperature. The dimensional stability of the HMLS fiber is limited by the heat treatment especially when the temperature exceeded Tg because a larger plastic deformation happen with the relaxation of molecular chain in amorphous phase.


Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 219
Author(s):  
Zhongguo Zhao ◽  
Xin Zhang ◽  
Qi Yang ◽  
Taotao Ai ◽  
Shikui Jia ◽  
...  

In this work, a series of isotactic polypropylene/poly(ethylene terephthalate) (iPP/PET) samples were prepared by microinjection molding (μIM) and mini-injection molding (IM). The properties of the samples were investigated in detail by differential scanning calorimetry (DSC), Wide-Angle X-ray Diffraction (WAXD), Polarized light microscope (PLM) and scanning electron microscopy (SEM). Results showed that the difference in thermomechanical history between both processing methods leads to the formation of different microstructures in corresponding iPP/PET moldings. For example, the dispersed spherical PET phase deforms and emerges into continuous in-situ microfibrils due to the intensive shearing flow field and temperature field in μIM. Additionally, the incorporation of PET facilitates both the laminar branching and the reservation of oriented molecular chains, thereby leading to forming a typical hybrid structure (i.e., fan-shaped β-crystals and transcrystalline). Furthermore, more compact and higher degrees of oriented structure can be obtained via increasing the content of PET. Such hybrid structure leads to a remarkable enhancement of mechanical property in terms of μIM samples.


e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Fan Xufen ◽  
Chen Dajun

AbstractPoly (ethylene terephthalate) (PET)/Attapulgite (AT) nanocomposites were prepared via in-situ polymerization. According to the observation of transmission electron microscopy (TEM), attapulgite is well dispersed in the PET matrix in a nanometer scale. The influence of attapulgite content on the nonisothermal crystallization kinetics was studied using a classical Avrami equation with Jeziorny method. The crystalline structures of the pure PET and PET/AT nanocomposites with different amount of AT (0.2%, 0.5%, 1%, 2%) were characterized by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) methods. It was found that the crystallization temperature for PET/AT nanocomposites with 0.2% and 0.5% content of AT were higher than pure PET and the rate of crystallization of all PET/AT nanocomposite samples increased significantly which indicated that attapulgite could be used as an effective nucleating agent in PET. However, with the addition of AT, smaller crystalline size, more crystalline defects and lower degree of crystallization was demonstrated.


2015 ◽  
Vol 30 (8) ◽  
pp. 1157-1172 ◽  
Author(s):  
Nevin Gamze Karsli

The aim of this study is to simultaneously improve the mechanical strength and fracture toughness properties of recycled poly(ethylene terephthalate) (r-PET). For this purpose, Joncryl® was used as chain extender and Lotader® was used as impact modifier. The combined effect of chain extender and impact modifier on the chemical, fractural, mechanical, and thermal properties of r-PET was investigated. Fourier transformed infrared spectroscopy (FTIR) analysis, EWF analysis, tensile test, and differential scanning calorimetry (DSC) analysis were performed. FTIR analysis revealed that all the epoxy groups in the Joncryl® were consumed during the compounding. EWF results showed that while toughness of r-PET decreased with the addition of Joncryl®, toughness was increased with addition of impact modifier Lotader®. It was found that 2.5% Lotader® usage at the same time with Joncryl® increased the tensile strength of r-PET as well as toughness. It was observed from DSC analysis that chain extender and impact modifier addition did not change the thermal transition temperatures of r-PET.


2011 ◽  
Vol 301-303 ◽  
pp. 104-108 ◽  
Author(s):  
Yu Sun ◽  
Guo Zheng ◽  
Hong Xiang Yang ◽  
Lan Zhou ◽  
Yan Jun Liu ◽  
...  

This study investigated the structures and properties of cationic dyeable poly(ethylene terephthalate) (CDP) and easy cationic dyeable poly(ethylene terephthalate) (ECDP) by FTIR, X-ray diffraction, mechanical test, and DSC. The results showed that the FTIR spectrums of CDP and ester-type ECDP fibers were similar to the that of PET. It suggested that the adding of the third monomer and the fourth monomer had good compatible with the original structure unit of PET. the position of X-ray diffraction peak of CDP and ester-type ECDP were the same as which of PET, the third monomer and the fourth monomer did not pack into the original polyester unit cell but concentrated at the polyester crystalline surface and the amorphous regions.With adding the third monmome and the fourth monmomer, the initial modulus of the CDP and ester-type ECDP fibers became inferior. But the breaking elongation of them increased. The DSC suggested that The melting range of CDP and ECDP finished fiber were wider than that of PET fiber, but the melting point and crystallinity were less than them of PET fiber.


2021 ◽  
Vol 22 (7) ◽  
pp. 3491
Author(s):  
Grażyna B. Dąbrowska ◽  
Zuzanna Garstecka ◽  
Ewa Olewnik-Kruszkowska ◽  
Grażyna Szczepańska ◽  
Maciej Ostrowski ◽  
...  

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.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1397 ◽  
Author(s):  
Elaine dos Santos ◽  
Marcus Fook ◽  
Oscar Malta ◽  
Suédina de Lima Silva ◽  
Itamara Leite

Purified clay was modified with different amounts of alkyl ammonium and phosphonium salts and used as filler in the preparation of PET nanocomposites via melt intercalation. The effect of this type of filler on morphology and thermal and mechanical properties of PET nanocomposites was investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile properties, and transmission electron microscopy (TEM). The results showed that the mixture of alkyl ammonium and phosphonium salts favored the production of PET nanocomposites with intercalated and partially exfoliated morphologies with slight improvement in thermal stability. In addition, the incorporation of these organoclays tended to inhibit PET crystallization behavior, which is profitable in the production of transparent bottles.


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