The effect of hot multistage drawing on molecular structure and optical properties of polyethylene terephthalate fibers

Haji, Aminoddin; Rahbar, Ruhollah Semnani; Kalantari, Bahareh

doi:10.1590/s1516-14392012005000076

Cited by 12 publications

(6 citation statements)

References 29 publications

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“…All films except PET exhibit a small or negligible inplane birefringence that aligns with the in-plane tensile test results. Processing conditions (e.g., drawing, stretching, and heating) have a significant effect on the variability of the in-plane birefringence [14,43,44]. PET and PEN exhibit high out-of-plane birefringence values compared with the other films.…”

Section: Optical Refractive Indices Birefringence and Waxsmentioning

confidence: 99%

Effect of Chain Orientation on Coupling of Optical and Mechanical Anisotropies of Polymer Films

Samadi-Dooki,

Lamontia,

Londoño

et al. 2024

Coatings

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Polymer films have broad applications in different industries with specific requirements for their optical and mechanical properties. In mass production, processing conditions during film formation that apply forces and motions in various directions to the film tend to manifest preferred molecular chain orientation in the film microstructure, which unavoidably produces optical and mechanical anisotropies. In this paper, we investigate the effect of such macromolecular orientations on the optical and mechanical anisotropies of several polymer films, including polystyrene, poly(methyl methacrylate), poly(ethylene terephthalate), poly(ethylene naphthalate), poly(ether ether ketone), poly(ether sulfones), poly(ethylene chlorotrifluoroethylene), poly(phenylsulfone), and polycarbonate, at temperatures well below their respective glass transitions (Tg). The film mechanical responses, including elasticity, yielding, and post-yield behaviors, were obtained for the in- and out-of-plane directions utilizing tensile and nanoindentation testing methods, respectively. In addition, the net chain orientation within the films was evaluated by birefringence through analyzing the film optical refractive indices, which were verified and complemented by wide-angle X-ray scattering (WAXS) measurements. The results reveal a considerable quantitative correlation between the birefringence and the degree of elastic anisotropy and a qualitative correlation between the chain orientation and the film post-yield tensile instability (necking). These observations corroborate the interrelationship between the microstructure of polymer films and their optical and mechanical properties. In addition, they emphasize that process conditions can be selected to tune the optical and mechanical anisotropies to best serve the material performance in specific devices. We also propose an empirical equation to approximate the out-of-plane film stiffness based upon the optical and in-plane mechanical properties.

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Section: Optical Refractive Indices Birefringence and Waxsmentioning

confidence: 99%

Effect of Chain Orientation on Coupling of Optical and Mechanical Anisotropies of Polymer Films

Samadi-Dooki,

Lamontia,

Londoño

et al. 2024

Coatings

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“…Another study dealt with the birefringence of PET fibers generated by hot multistage drawing [ 48 ]. The experiments were carried out on a Zeiss polarizing microscope coupled with a tilting compensator.…”

Section: Optically Birefringent Polymer Materials and Their Applicationsmentioning

confidence: 99%

Review on Optical Methods Used to Characterize the Linear Birefringence of Polymer Materials for Various Applications

et al. 2023

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Optical polymers are recognized for their high transparency, raised flexibility, low cost, and good film-forming ability; hence, they introduce a multitude of benefits in a wide range of devices, such as information storage, displays, optical communications, and filters. Among the optical properties, birefringence is an essential parameter in practical cases that demand the control of the state of polarization of light. This review is focused on describing some fundamental and applicative aspects concerning the optical birefringence of the polymer materials. First, elementary notions depicting the phenomenon of light double refraction in macromolecular media are provided. Furthermore, the most relevant optical techniques to determine birefringence are reviewed by highlighting the working principle and mathematical basis for computing this parameter. Then, a series of investigations of optically birefringent polymers are described, summarizing the most utilized approaches to induce light double refraction in such materials. The selected results are analyzed in relation to the pursued applications. In the end, the future of this scientific domain is briefly presented by establishing the research paths that need further exploration. Moreover, the novel directions that could be formulated and might contribute to certain considerable advancements in the materials employed in the modern optical technologies are mentioned.

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“…2 Thermal and mechanical loading of polymers leads to microstructural changes, and these relationships have been documented before. [17][18][19][20] Using XRD, we compared microstructural signatures of virgin and abraded fabrics to signatures acquired from more fundamental experiments. These comparisons will generate microscale understanding of the fabric abrasion deformation process.…”

Section: Macroscopic Failure Also Indicates Significant Microstructural Changesmentioning

confidence: 99%

Understanding thermomechanical failure of athletic textiles via the pendulum skid method

Gregory

Swarup

et al. 2018

Textile Research Journal

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Fiber textiles worn by some athletes and basketball and volleyball players experience higher than usual thermomechanical stresses compared to everyday garments because these athletes slide and dive on hardwood courts. Common textile testing procedures, such as the Martindale abrasion tester, effectively test textiles under modest loads and thousands of cycles, but this methodology does not suffice for athletic textiles. In addition, there is not a robust model nor a repeatable test that mimics high thermomechanical stress on fabrics and provides insights on fabric abrasion resistance. We present a model to calculate the temperatures and strain rates that are seen by fabrics undergoing thermomechanical deformation. To enable validation of the model, a fabric pendulum abrasion tester, an adaptation of the Cooper pendulum skid tester, was developed. The tester characterizes high-strain fabric abrasion deformation. This adaptation is statistically reliable and induces repeatable and realistic fabric failure within tens to hundreds of cycles, proving to be analogous to the loads athletes place on their textiles. Analog electronics on the pendulum abrasion tester generate real-time temperature and velocity profiles. A series of 11 unique athletic fabrics were abrasion tested, and it was found that fabrics with macroporosity experience the largest abrasion degradation. Significant degradation sites were further explored using scanning electron microscopy and X-ray diffraction analysis, and it was shown that thermomechanical loading’s effect on fiber microstructure is a function of the fabric construction. This novel abrasion tester and quantitative relationships between fabric structure and degradation mechanisms will enable more data-driven decisions when designing textiles for thermomechanical loads.

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The effect of hot multistage drawing on molecular structure and optical properties of polyethylene terephthalate fibers

Cited by 12 publications

References 29 publications

Effect of Chain Orientation on Coupling of Optical and Mechanical Anisotropies of Polymer Films

Effect of Chain Orientation on Coupling of Optical and Mechanical Anisotropies of Polymer Films

Review on Optical Methods Used to Characterize the Linear Birefringence of Polymer Materials for Various Applications

Understanding thermomechanical failure of athletic textiles via the pendulum skid method

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