Crystalline and amorphous deformation of process-controlled cellulose-II fibres

Kong, Kenny; Eichhorn, Stephen J.

doi:10.1016/j.polymer.2005.04.096

Cited by 60 publications

(75 citation statements)

References 36 publications

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“…So a smaller diameter could yield a higher modulus. Our values for the predicted moduli of the fibrils do exceed those obtained for the same batch of micron-sized fibres (~26 GPa) [48] which suggests that some reduction in the lateral size of the fibres results in an increase in the modulus. This increase in modulus could occur due to the inherent lateral crystal dimension becoming more significant at smaller fibre diameters.…”

Section: Mechanical Propertiescontrasting

confidence: 77%

Stress transfer in microfibrillated cellulose reinforced poly(vinyl alcohol) composites

Tanpichai

Sampson

Eichhorn

2014

Composites Part A: Applied Science and Manufacturing

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Combined homogenization and sonication treatments of micron-sized lyocell fibres were used to generate microfibrillated celluose (MFC) with fibril diameters of ~350 nm. No further reduction in fibril diameter was observed after 30 minutes treatment. Poly(vinyl alcohol) (PVA) composites reinforced with these fibrils were fabricated using solvent casting and physical and mechanical properties were investigated. The presence of MFC in PVA increased the thermal degradation of the polymer. An increase in both the tensile strength and modulus of the composites was observed for up to 3 wt.% of fibrils; beyond this point no significant increases were observed. An estimate of ~39 GPa is made for the fibril modulus based on this increase. Stress-transfer between the polymer resin and the fibrils was investigated using Raman spectroscopy. Stress transfer in the composite is shown to be greater than that of a pure network of fibres, indicating a good fibre-matrix bond.

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Section: Mechanical Propertiescontrasting

confidence: 77%

Stress transfer in microfibrillated cellulose reinforced poly(vinyl alcohol) composites

Tanpichai

Sampson

Eichhorn

2014

Composites Part A: Applied Science and Manufacturing

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“…This permanent change in preferred orientation caused an improved modulus of elasticity (34.4 ± 4.9 GPa vs. 24.5 ± 3.5 GPa), reduced elongation at break (4.8 ± 1.2% vs. 10.1 ± 1.2%), but no significant change in tensile strength (605 ± 48 MPa vs. 612 ± 52 MPa). It is thus demonstrated that a change in the degree of preferred orientation, in the present case induced by 8% stretching corresponding to a draw ration of only 1.08, has significant effects on the modulus of elasticity and the elongation at break, but not the tensile strength, which is significantly different from the effect of drawing during the spinning process (Kong and Eichhorn 2005).…”

Section: Resultsmentioning

confidence: 51%

“…These structural differences may well serve to explain the observed different behaviour in tensile tests. On a set of lyocell fibres spun with different draw ratio a strong dependence of mechanical properties on the degree of preferred orientation was shown (Kong and Eichhorn 2005): in general, the tensile strength and the modulus of elasticity of a fibre increase with increasing degree of preferred orientation, whereas the elongation at break decreases in turn. The lyocell fibre tow and staple fibre studied here obey this relationship regarding their modulus of elasticity and elongation at break.…”

Section: Resultsmentioning

confidence: 99%

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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“…Eichhorn et al 2003Eichhorn et al , 2005Kong and Eichhorn 2005a) and by Northolt and co-workers (e.g. Northolt and Baltussen 2002).…”

Section: Introductionmentioning

confidence: 98%

“…Typical lyocell staple fibres show a tensile strength of 750 MPa, an elastic modulus of 22 GPa, and an elongation at break of 8% . By varying chemical parameters and process parameters, the cross-sectional shape and mechanical properties of regenerated cellulose fibres may be tuned within a wide range (Lenz et al 1994;Kong and Eichhorn 2005a), and a tensile strength of up to 1300 MPa and an elastic modulus of up to 45 GPa may be achieved (Northolt et al 2001). In absolute terms, these values are not truly competitive with glass fibre, but considering the low density of 1.5 g cm )3 of cellulose compared to 2.5 g cm )3 for glass, comparability is given on a weight basis.…”

Section: Introductionmentioning

confidence: 99%

Orientation of cellulose crystallites in regenerated cellulose fibres under tensile and bending loads

et al. 2006

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The degree of orientation in regenerated cellulose fibres with a diameter of 36lm was determined using position-resolved synchrotron X-ray microbeam diffraction. The fibres were characterized in unstrained condition, under tensile strain, and in bending. A homogeneous distribution of the degree of crystalline orientation (Herman's orientation factor f c = 0.85) across the fibre thickness was found in the unstrained fibre. The degree of orientation of cellulose crystallites increased in a linear manner with increasing tensile strain applied to the fibre. Also in bending, a linear relationship between applied strain and the degree of crystalline orientation was found, where f c increased in tension and decreased in compression. This linear relationship was found to be valid for both the tensile and the compressive zone of the bent fibre.

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Crystalline and amorphous deformation of process-controlled cellulose-II fibres

Cited by 60 publications

References 36 publications

Stress transfer in microfibrillated cellulose reinforced poly(vinyl alcohol) composites

Stress transfer in microfibrillated cellulose reinforced poly(vinyl alcohol) composites

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

Orientation of cellulose crystallites in regenerated cellulose fibres under tensile and bending loads

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