Layer structure formation in oriented poly(ethylene terephthalate) relating to micromechanical properties

Uchiyama, Takumi; Suyama, Motohiro; Alam, Mohammad Mahay; Asano, Tsutomu; Henning, Sven; Flores, A.; Calleja, F. J. Baltá; Mina, Md. Forhad

doi:10.1016/j.polymer.2006.11.030

Cited by 25 publications

(17 citation statements)

References 20 publications

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“…3. The microhardness technique appears to be a valuable tool for studying the kinetics of the development of the mesophases, and the crystallinity of oriented polymer samples, this comes in agreement with recent publications relating both techniques [24].…”

Section: Discussionsupporting

confidence: 87%

Microindentation technique as a tool for investigating the development of order in PET under uniaxial stress

Abou-Kandil¹,

Flores²,

Calleja³

et al. 2008

J Polym Res

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The development of microhardness during annealing was used as a tool to follow the development of the liquid crystalline transient mesophase during the crystallization of uniaxially oriented polyethylene terephthalate (PET). 2D X-ray diffraction was used to characterize the different stages of the crystallization process. We were able to separate those stages by quenching into air. Microindentation hardness experiments were done in real time where samples were heated with their ends fixed on a specially developed stage and microhardness was measured simultaneously. The oriented samples examined exhibit a clear difference in behavior from isotropic samples that mainly lack the existence of such an ordered mesophase. The mesophase clearly has a reinforcement effect on the whole polymer matrix that leads to an increase in hardness value with annealing of the oriented PET films. Microindentation hardness is shown to be a versatile tool to detect the existence of the liquid crystalline transient mesophase. It is also efficient in comparing and explaining results obtained by wide angle X-ray scattering.

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Section: Discussionsupporting

confidence: 87%

Microindentation technique as a tool for investigating the development of order in PET under uniaxial stress

Abou-Kandil¹,

Flores²,

Calleja³

et al. 2008

J Polym Res

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“…So, it can be maintained that crystallization is responsible for the increasing total trans content when samples are drawn at a temperature above the T g but for temperatures below or near T g , the development of the transient structure is responsible for the increase in the trans isomer content. These results are consistent with those reported in the literature, confirming that the development of a transient structure strongly depends on process temperature and that for an identical draw ratio, PET yarns drawn at 23 o C are significantly more oriented than those drawn at 68 o C .…”

Section: Resultsmentioning

confidence: 73%

Effect of drawing temperature on the structure and free volume of semicrystalline polyester yarns

Baseri

2014

Polym Eng Sci

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Supercritical carbon dioxide (scCO 2 ), an environmentally friendly solvent, can change the fine structure of fibers depending on treatment temperature and pressure. This article presents the results of an investigation into the effects of drawing temperature, scCO 2 exposure and tension on structural changes, and mesomorphic transitions in partially oriented yarn (POY) and oriented poly(ethylene terephthalate) (PET) yarns. Samples of POY and PET yarns were uniaxially drawn at different temperatures to obtain filaments with different structures for subsequent exposure to scCO 2 in the presence and absence of tension at a temperature of 80 o C and under a pressure of 220 bar. Structural investigation of the samples was performed by combining the results obtained from differential scanning calorimetry, Fourier transform infrared, mechanical deformation, and density and birefringence measurements, all of which exhibited a good correlation. The fractional free volume in the PET samples was considered for interpreting structure-property relations. Results showed that the development of a transient structure strongly depends on process temperature and that for an identical draw ratio, PET yarns drawn at 23 o C are significantly more oriented than those drawn at 68 o C. Two crystallization mechanisms, that is strain-induced and thermal-induced crystallization, are involved that are frequently used to explain the structural changes during yarn deformation at different temperatures. The degree of crystallinity and orientation factors for PET yarns does not proportionally increase with increasing temperature of the drawing process; indeed, the highest value is obtained at a temperature of 100 o C, whereas the lowest is observed at a temperature of 68 o

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“…22 development of the triclinic PET structure and its lamellae interpretation is that of a herringbone [48][49][50] or paracrystalline morphology [51] (Figure 7 (D)). The PET1% and PET2% composites again show a fibril or shish-kebab type of structure, but still significant diffuse scattering is observed in the SAXS patterns arising from the MWCNTs and imperfect PET crystallites.…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Structure evolution in poly(ethylene terephthalate) (PET) – Multi-walled carbon nanotube (MWCNT) composite films during in-situ uniaxial deformation

Heeley

Hughes

Crabb

et al. 2016

Polymer

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Keywords: polymer multi-walled carbon nanotube composites; Small-and Wide-Angle X-Ray Scattering (SAXS/WAXS); crystalline morphology evolution, nucleating agents. ABSTRACTCombined small-and wide-angle X-ray scattering (SAXS/WAXS), mechanical and thermal techniques have been used to follow the morphology evolution in a series of poly(ethylene terephthalate) (PET) multiwall carbon nanotube (MWCNT) composite films during quasi solidstate uniaxial deformation at low strain rates. Uniaxially deformed PET-MWCNT films displayed improved mechanical properties compared with unfilled PET films. SAXS/WAXS data revealed a well oriented lamellar structure for unfilled PET films. In contrast, the PET-

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Layer structure formation in oriented poly(ethylene terephthalate) relating to micromechanical properties

Cited by 25 publications

References 20 publications

Microindentation technique as a tool for investigating the development of order in PET under uniaxial stress

Microindentation technique as a tool for investigating the development of order in PET under uniaxial stress

Effect of drawing temperature on the structure and free volume of semicrystalline polyester yarns

Structure evolution in poly(ethylene terephthalate) (PET) – Multi-walled carbon nanotube (MWCNT) composite films during in-situ uniaxial deformation

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