Internal Damage of Crimped Lyocell Fiber

Dadashian, Fatemeh; Yaghoobi, Z.; Wilding, M. A.

doi:10.1177/0040517507080543

Cited by 6 publications

(6 citation statements)

References 10 publications

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“…The modulus of elasticity of staple fibres is only 50% of the modulus of fibre tow from the same production lot. This reduction in the modulus of staple fibres exceeds the value found for uncrimped and crimped lyocell from a different source published recently (Dadashian et al 2007), where 30% reduction was measured.…”

Section: Resultscontrasting

confidence: 55%

“…1) having made through the additional processing steps of cutting, washing, and press-drying. Differently from the fibres studied by Dadashian et al (2007) the production process did not comprise controlled crimping in a stuffer box.…”

Section: Methodsmentioning

confidence: 99%

“…After spinning, where a manifold of parameters influences the formation of structure in fibres (Fink et al 2001), the mechanical properties of a fibre are basically set, given that no further treatments such as cross-linking are performed. A recent study by Dadashian et al (2007) showed that crimping of lyocell fibres performed in a stuffer box induces structural damage (kink bands) with concurrent loss of strength and modulus of elasticity. With fibres originating from a different source and with different methods, it is confirmed in the present study that the processing of fibres until they reach their final condition as staple fibres may very significantly degrade certain fibre properties.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of molecular orientation and mechanical properties of lyocell fibre tow and staple fibres

et al. 2009

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Samples of lyocell fibres were taken in the form of filaments from fibre tow of potentially infinite length and in their final condition of staple fibres. Mechanical testing showed comparable tensile strength, but a 50% lower modulus of elasticity for staple fibres and a higher elongation at break compared to filaments from fibre tow. Structural investigation by means of synchrotron wide angle X-ray scattering and birefringence measurement revealed a significantly lower degree of preferred orientation together with less fibre straightness for staple fibres than for filaments. It is concluded that plastic deformation during the processing of staple fibres from filaments induces permanent changes in the orientation of cellulose chains in the fibres, which in turn is responsible for the observed differences in mechanical performance.

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Section: Resultscontrasting

confidence: 55%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparison of molecular orientation and mechanical properties of lyocell fibre tow and staple fibres

et al. 2009

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“…As shown in Figure 3, the broad peak in the region of 3000–3800 cm −1 has been attributed to the stretching motions of OH groups. The intensity and frequency of this band are related to the intra‐molecular hydrogen bonding 21. It is also revealed that the absorption bands, appearing in this region are heightened and broader after hydrolysis, in the case of the Lyocell sample.…”

Section: Resultsmentioning

confidence: 83%

Effect of phase separation on spherulitic growth rate of PP/EPR in‐reactor alloys

Liu¹,

Li²,

Xu³

et al. 2011

J of Applied Polymer Sci

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In this work, the effect of phase separation on the spherulitic growth rate of a polypropylene/ethylene-propylene random (PP/EPR) copolymer in-reactor alloy was investigated. The PP/EPR in-reactor alloy was either directly quenched from homogeneous melt to crystallization temperature or held at various temperatures for phase separation prior to crystallization. It is found that at lower crystallization temperatures previous phase separation in the melt retards the crystallization rate. The higher the phase separation rate, the smaller the spherulitic growth rate. This can be attributed to faster crystallization rate than the rate of secondary phase separation. The composition of the PP-rich phase and corresponding depression of the equilibrium melting temperature of PP vary with phase separation temperature. On the other hand, at higher crystallization temperature, previous phase separation in the melt has little effect on the spherulitic growth rate because secondary phase separation can take place prior to crystallization. The transition temperature from regime II to regime III also shifts to lower temperature as the phase separation temperature increases.

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“…The intensity and frequency of this band are related to the intra-molecular hydrogen bonding. 21 It is also revealed that the absorption bands, appearing in this region are heightened and broader after hydrolysis, in the case of the Lyocell sample. This suggests that the treated sample of Lyocell contained more hydrogen bonds than the untreated one and there are no significant changes of treated viscose.…”

Section: Ftirmentioning

confidence: 88%

Enzymatic modification of regenerated cellulosic fabrics to improve bacteria sorption properties

Akbari

Dadadashian

Kordestani

et al. 2012

J Biomedical Materials Res

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This research investigates the effect of enzymatic treatment of two different regenerated cellulosic fibers (Lyocell and viscose) on their ability of bacteria sorption from an aqueous suspension. The sorption of Escherichia coli (E. coli, Gram negative) and Staphylococcus aureus (S. aureus, Gram positive) cells by treated Lyocell and viscose fabrics were determined by measuring the optical density (OD) of the remaining bacteria suspension after removal of the fabric samples using spectrometry. Fourier transform infrared spectroscopy and scanning electron microscopy (SEM) were utilized to investigate structural and morphological changes of the enzyme treated samples. The result showed that the moisture content and crystallinity of both viscose and Lyocell samples increased after enzymatic treatment. Comparing the results of OD measurements indicated that enzymatic treatment of cellulosic samples significantly increased the bacteria absorption properties compared to those untreated samples. However, treated samples showed different ranges of sorption ability with different kinds of bacteria. The maximum bacteria sorption of 38% and 37% of E. coli bacteria from an aqueous suspension was found for the treated viscose and Lyocell samples compared with only 20% and 10% of the untreated viscose and Lyocell samples, respectively. It was also found that S. aureus sorption of cellulose-treated viscose and Lyocell fabrics from a bacterial suspension could significantly improve up to 33% compared with only 5% of untreated samples. Furthermore, SEM micrographs confirmed that bacterial sorption of the cellulose-treated samples were effectively improved in terms of their uniform sorption on the fibers surface.

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Internal Damage of Crimped Lyocell Fiber

Cited by 6 publications

References 10 publications

Comparison of molecular orientation and mechanical properties of lyocell fibre tow and staple fibres

Comparison of molecular orientation and mechanical properties of lyocell fibre tow and staple fibres

Effect of phase separation on spherulitic growth rate of PP/EPR in‐reactor alloys

Enzymatic modification of regenerated cellulosic fabrics to improve bacteria sorption properties

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