Table 6 - uploaded by Aminoddin Haji
Content may be subject to copyright.
Godet roller speed for yarn drawing

Godet roller speed for yarn drawing

Source publication
Article
Full-text available
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, a...

Context in source publication

Context 1
... an equivalent drawing speed (here is 400 m/min), the fibers spend a much more time for draw- ing in three-steps than in single and two-steps. By considering the number of wraps of yarn around each godet roller and godet rollers speeds as given in Table 6, at drawing speed of 400 m/min, the drawing residence time on draw godet rollers is 0.28, 1.83, and 2.09 s for the DR1, DR2, and DR3 samples, res- pectively. Thus in the case of DR3 sample, much more gradual changes in molecular structure over the drawing period occurred as compared to those drawn at single and two-stage drawing at equivalent total draw ratio and drawing speed. ...

Citations

... S. J. M. Van Den Heuvel et al. reported a conformational transition from gauche to trans in PET yarns observed during mechanical stretching [60]. There is also a tendency toward the crystallization of amorphous PET induced by mechanical stretching between glass transition and melting temperatures [61,62]. These interactions and resulting structural characteristics play a crucial role in determining the mechanical properties of the material. ...
Article
Full-text available
Polyethylene terephthalate (PET) is one of the most used polymeric substances in production of packaging materials, fibers, textiles, coatings, and engineering materials. This paper elucidates the transport parameters of hydrogen gas through a PET membrane, which was selected to be a sufficiently permeable substrate for setting up an empirical strategy that aims at developing hydrogen barrier coatings. An examination of the structural degradation of PET by prolonged hydrogen exposure was performed. Hydrogen permeation tests were performed on a PET membrane with a thickness of 50 µm. To investigate the behavior of the material by prolonged hydrogen treatment, hydrogen-exposure experiments were carried out at a certain hydrogen pressure and time. Comparisons of the mechanical properties of the material were documented both before and after hydrogen exposure. A strong impact of comparatively transient hydrogen exposure on the mechanical and hydrogen transport properties of PET was observed. After 72 h of hydrogen exposure at 1000 hPa and 300 K, the tensile strength decreased by 19%, the diffusion coefficients more than doubled, and material fracture behavior changed from ductile to distinctly brittle. This underlines the importance of developing effective hydrogen barrier coatings in case PET tubing is intended for use in hydrogen transport or storage. ......................................................................................................................................... This article belongs to the Special Issue "Hydrogen Storage and Transportation: Materials, Technologies, and Infrastructure Development".
... is another common method that is used to describe morphology through information on first and second order transitions [24] and Dynamical Mechanical Analysis (DMA) is a method that provides information about structure and property relationships [25][26]. Substantial effort has been put into studying microstructure of PET both as film [27][28][29][30][31] and fibre [32][33][34][35] and these studies provide good information on how data shall be obtained and interpreted when applying these methods on SrPET. ...
... Shrinkage could be a problem for these products because it can influence the shape and dimension. Further, results from crystallinity evaluation of annealed and thereby shrunk fibres are presented in As mentioned earlier, previous studies made on PET fibres have showed that shrinkage is attributed to disorientation of non-crystalline regions [33]. This study has shown that the crystalline phase is unaffected from stretching and that shrinkage increase with degree of stretching, thus why we can say that stretching SrPET material in a heated state before compression moulding influence the non-crystalline regions in the HTPET fibres. ...
Article
Self-reinforced poly(ethylene terephthalate) laminates were prepared from woven fabric by compression moulding. The fabric was stretched to different degrees during heating before hot consolidation to simulate a manufacturing process where the material is stretched through forming. High tenacity poly(ethylene terephthalate) fibres with different degrees of stretching were prepared for a comparison to laminates. Tensile tests were made to characterize mechanical properties, while dynamical mechanical analysis, differential scanning calorimetry, FTIR spectroscopy and X-ray diffraction analysis were employed to study microstructural changes caused by the stretching. Tensile tests show that 13% stretching of the fabric increases the laminate tensile stiffness by 34%. However, same degree of stretching for pure fibres increases the fibre tensile stiffness by 111%. Crystallinity and molecular conformations are not influenced by stretching while shrinkage upon heating increases with degree of stretching. Shrinkage is known to be related to disorientation of non-crystalline regions whereof the conclusion from this study is that the increased tensile properties are due to orientation of the non-crystalline regions of the fibre.
... There are described investigations of the relationships between treatments of PET with different initial structures and the caused phase and structure evolution [1][2][3][4][5]. The effects of the strain force, strain rate and temperature on the structure development of PET filaments have been well studied and reported by a number of researchers [6][7][8][9][10][11][12][13][14][15][16][17][18] including the authors of the present article. It is studied the influence of the treatment and production conditions on the fibers deformation behavior [6,7] mechanical properties [8,9,14] and spinning process [17]. ...
... The effects of the strain force, strain rate and temperature on the structure development of PET filaments have been well studied and reported by a number of researchers [6][7][8][9][10][11][12][13][14][15][16][17][18] including the authors of the present article. It is studied the influence of the treatment and production conditions on the fibers deformation behavior [6,7] mechanical properties [8,9,14] and spinning process [17]. ...
Article
Full-text available
The present work is devoted to the investigation of the structure developments in as- spun amorphous poly (ethylene terephthalate) (PET) filaments occurred as a result of heat mechanically modification. The degree of crystallinity of the untreated samples was 1,7 %. The thermal deformation experiments were carried out under isothermal conditions. PET yarn was annealed during 10 min at constant temperature of 80?C after which the sample is subjected to a well-defined constant tensile stress for 120 s at the same temperature. The mechanical load is gravitationally in the range from 0 MPa to 30 MPa and with increment step of 3 MPa. Using of wide angle X-ray scattering (WAXS) were investigated the structural rearrangements in the studied samples caused by the fibers treatments. Dependences between the strain force values and the running in the specimen's structure development are established. And in particular, it was found that a small increase of the tensile stress from 3 MPa to 6 MPa leads to a massive increase in the fibers degree of crystallinity with more than 33%.
... where A t is the total area under the curve of the diffracted intensity at 2h = 5°to 45°, and A a is the corresponding area under the baseline [20]. The crystal size (L) was determined from the half-height width of the crystalline reflections using the Scherrer Equation [21]: ...
... Lateral order index (LOI) can be related to several factors such as the crystallinity, reflection, size, and the distribution of the crystallites [21]. It reflects, the ordered regions perpendicular to the chain direction and was calculated from the following equation: ...
Article
Full-text available
The aim of this study was to evaluate the effect of oxygen plasma treatment on the surface roughness, morphology, chemical surface structure, crystallinity and tensile properties of wool fiber yarn. The wool fibers were treated with oxygen plasma at a different treatment time. The morphological surface characterization of wool fibers was realized at sub-micro scale by means of high-resolution scandisk confocal microscopy and scanning electron microscopy. The chemical structure of untreated and plasma treated wool fiber surface was analyzed by Attenuated Total Reflectance Fourier Transform Infrared spectrometry. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer. The results showed that oxygen plasma treatment leads to the removal of surface lipids and oxidizes the cysteine in the exocuticle and increases the surface roughness.
... PET filaments are known to have a higher stiffness in comparison to other polymer textile fibers[39,40]. This is mainly due to its tendency to develop a conformation with stretched polymer chains together with the presence of aromatic rings in thepolymer's backbone[40,41], as shown infigure 1. One of the main parameters affecting the compressive properties of polymer fibers is their ability to form lateral intermolecular interactions[7], which in most cases consist of secondary type of bonding. ...
Article
Full-text available
High-speed melt spinning of a cyclo-olefin polymer (COP) and a copolyamide (CoPA) have been performed. Differential scanning calorimetry curves of the resulting monofilaments show that they remain in an amorphous state even after hot drawing. Wide angle x-ray diffraction patterns of undrawn and drawn COP filaments show that although the material remains in an amorphous state, a degree of orientation is induced in the polymer after drawing. The amorphous filaments show an enhanced bending recovery with respect to different semi-crystalline monofilaments commercially available. However, single fiber axial compressive testing indicates that the amorphous filaments exhibit a compressive modulus value which is 50% lower than what is observed for a reference semi-crystalline PET filament. Analysis of the compressive strains applied by the bending recovery test indicates that while the maximum applied strains remain well within the region of elastic deformation of the amorphous materials, the threshold between elastic and plastic deformation is reached for the semi-crystalline materials.
... The structure formations in uniaxially oriented amorphous PET under drawing conditions have been reported in several studies (Asano et al., 1999;Bhat & Naik, 1984;Goschel, 1996;Hotter et al., 1998;Keum et al., 2003;Keum & Song, 2005;Kim et al., 2011;Oultache et al., 2001;Perena, Duckett, & Ward, 1980;Radhakrishnan & Kaito, 2001;Reitsch, Duckett, & Ward, 1979;Todorov, Martins, & Viana, 2012). Although, different aspects of drawn PET fiber have been subject of many publications, there is a lack of information concerning the effect of hot multistage drawing on the microstructure of PET fiber (Haji & Rahbar, 2012). Therefore, this paper is devoted to monitor the orientation and crystallinity changes induced during hot multistage drawing of PET fiber. ...
Article
In this research, poly(ethylene terephthalate) (PET) multifilament yarn was drawn on an industrial drawing machine at hot multistage. By varying draw ratio, a number of drawn fibers with different internal structures were obtained. Total draw ratio was changed from 4.68 to 6.24. Crystallinity and molecular orientation of the drawn samples were investigated using differential scanning calorimetry, birefringence, infrared spectroscopy, and X-ray diffraction. The results show that the high population of gauche conformer in as-spun fiber decreased rapidly with fiber orientation. The absence of crystallization peak and clear Tg in the drawn samples has been explained by orientation development as well as crystalline–amorphous interactions. Microstructural changes in the drawn PET fibers have been discussed in terms of the applied heat and mechanical deformation upon hot multistage drawing.
Article
This study was conducted on the visible–near-infrared camouflage properties of olive hue poly(ethylene terephthalate) multifilament mass dyed yarn textured by two texturizing method (simultaneous and conventional). The effect of thermal process and structural changes on the reflectance, mechanical, and crimp properties of these yarns was studied using the DSC, XRD, and birefringence analyses. It was observed that simultaneously textured mass dyed multifilament yarns have higher crimp properties and lower mechanical properties. Furthermore, the effect of yarns’ geometry in the fabric structure on the reflectance properties was investigated using images of fabric structure. The results showed that the reflectance behavior of fabric sample is affected by two major factors, namely structural and geometrical factors; it is clear that the geometrical factor has a significant effect on the reflectance properties.
Article
Inclusion complexes formed from host small molecules and guest polymers have provided a novel platform to study both the physical properties of isolated polymer chains and crystallization behavior of host molecules. In this report, we have studied the crystalline structure, melting behavior and infrared information of inclusion complexes formed between polyethylene glycol oligomers and urea molecules. The effect of molecular weight and terminal group of guest PEG oligomer on the melting behavior of inclusion complex is presented. FTIR spectra reveal that terminal –OH of PEG is hydrogen-bonded to urea in inclusion complex, while the terminal –OCH3 is free. The melting behaviors of complexes are interpreted using either Gibbs–Thomson equation for lamellar crystals with definite channel length or Flory equation for crystals with infinite channel length and included defects. The results show that the interaction between terminal –OH in PEG chain and urea induces larger interfacial free energy or stronger defect effect, compared to the terminal –OCH3 in the inclusion complexes, which results in the particular order of melting point: Tm(DPEG500UIC) > Tm(MPEG550UIC) > Tm(HPEG600UIC).
Article
Full-text available
Hyperbranched polyester (HBPET) with aliphatic–aromatic structure was synthesized and extruded with recycled poly (ethylene terephthalate) (RPET) chips obtained from used water bottles, with ratio of 0.5% and 1 wt% of HBPET. Filament fibers from pure recycled PET (RPET-0) and (RPET-0.5 and RPET-1) composite were spun using a melt spinning process and drawn by a thermal drawing process to improve their mechanical properties. The effects of addition of HBPET on the properties of produced fibers as well as draw ratio are investigated by means of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (XRD), universal tensile analysis, and sonic velocity. It was found that mechanical properties of the (RPET-0.5 and RPET-1) fibers were improved with respect to pure recycled PET (PET-0) fibers. Moreover, the crystallinity of composites fibers was also increased with an increasing of HBPET content. The improvement in mechanical properties may be due to the increase of orientation of fiber molecules along the fiber axis. Moreover, addition of HBPET serves as lubricant within recycled PET matrix which increased its mechanical properties.
Article
In this article, we present an experimental design methodology for studying the effect of the draw ratio on the physical properties of nylon 6 fibers on hot multistage drawing. A response surface methodology involving D-optimal design was used for the modeling and optimization. According to the analysis of variance results, the proposed models could be used to navigate the design space. We found that the responses of the tenacity and initial modulus were very sensitive to the factor of the second-stage draw ra-tio, and the shrinkage response was governed by the factor of the third-stage draw ratio. The results show a good agreement between the experimental and model predictions with high correlation coefficients. The operation conditions for obtaining the drawn yarn with the highest tenacity and initial modulus and low shrinkage are proposed. V C 2013 Wiley Periodicals, Inc. J. Appl.