The Crimp of Alkali Treated Jute Fibers
19
Citation
10
Reference
10
Related Paper
Citation Trend
Abstract:
An investigation of the formation of crimp on jute fibers by the action of alkali is presented. Jute fiber-like strands are treated with various concentrations of NaOH under various conditions of temperature and time. As the result of the treatment, crimp is formed on some of the samples prepared. The measurements of crimp are carried out by a method developed by this Institute for single fibers which is adapted to the jute. The crimp diameter, the crimp ratio, the extension, and the wave number are quantitatively determined for the various jute samples as a function of the load applied to the fiber. An uncrimping energy of extension which sums up the extension over the range of loads used is measured. No crimp is formed at NaOH concentrations lower than 6%. At higher concentrations the crimp parameters increase to maximum values at 9% alkali, and thereafter decrease to constant levels. The crimp is formed after 0.5 hr. of treatment. The optimum temperature for the formation of the crimp is around 2° C. With increase in temperatures the values of the crimp parameters decrease, and at 40° C. no crimp is observed.Keywords:
Crimp
The wools described in Part I were processed on the French-worsted system, and the yarns were woven into fabric. The specifications of the original experimental design1 were met reasonably well at the greasy-wool stage. As a result of fibre breakage during processing, however, crimp and length became confounded in terms of the original design. In the context of this study, this means that, effectively, only the consequences of variations in fibre diameter and crimp may be ascertained, with the effects of fibre length assumed to be negligible. The uncrimping behaviour of the 6 wools, as estimated from single-fibre load-extension curves, has been found to agree well with the level of crimp in the greasy-wool staples. The usual inverse relationship between uncrimping stress and Young's modulus obtains, and the stresses at 20% extension for the fibres from all 6 wools are statistically indistinguishable. The fibres from the high-crimp wools, however, exhibit lower breaking stresses, breaking extensions, and breaking energies. With top and roving, fibre crimp appears to be the most important factor in explaining the behaviour of the fibre assemblies. The largest elastic moduli and breaking stresses are shown by the three high-crimp wools; the lowest values for these properties are generally exhibited by the two low-crimp wools; and intermediate values by the one wool of intermediate crimp. The mechanical behaviour of yarn reflects the behaviour of the constituent fibres beyond the uncrimping region of the fibre load-extension curve. Crimp enters the picture indirectly, since fibres of higher crimp have lower elastic moduli and breaking stresses and extensions. Correspondingly, the yarns made from these fibres show the same lower mechanical properties. Both fibre diameter and crimp enter the picture when the bulk-compression properties of the yarns are considered, and the highest yarn specific volumes are generally associated with the two high-diameter, high-crimp wools. Diameter and crimp often appear to be of relatively equal importance in their relationship to fabric properties. The crease-recoveries (65% r.h.) of the six wools in fabric form are high and statistically indistinguishable from one another. Finished fabrics exhibit greater crease-recovery than R.T.D. (ready-to-dye) fabrics, and wetting-out lowers the crease-recovery. To a limited extent, extension-cycling tests carried out on the fabrics yield results in some accord with the crease-recovery tests in that the finished fabrics have greater elasticities, the largest elasticities being generally those of the three high-crimp wools, although the one wool of high diameter and low, crimp had large elasticity in the finished fabric. On the basis of earlier studies, it would be expected that this same wool would show the largest fabric flexural rigidity, and this has been found to be the case. Similarly, the smallest fabric flexural rigidity is exhibited by the one wool of low diameter and high crimp. The breaking properties of the fabrics are similar to those of the constituent yarns and fibres : the weaker fabrics are generally those prepared from the high-crimp wools.
Crimp
Worsted
Carding
Breaking strength
Cite
Citations (6)
Yarn axis geometry in plain‐weave fabrics has been described by different models. Yet, they do not capture its exact shape, because (1) the geometry of each crimp wave in a fabric is unique to that fabric and as such it differs from any generalized model, and (2) the length of the yarn axis, an important parameter, is more influenced by the height of the crimp wave than by any arbitrary definition of its shape. Crimp of the warp/weft is defined as the ratio of the length of the yarn axis in one wave and its wave length; the latter is the spacing (pitch) of the neighboring weft/warp yarns. Crimp can be calculated in accordance with the crimp wave shape definition, which differs from reality. In this paper, a new and very simple method of calculating the yarn crimp is proposed and validated through experimental measurements. The results provide an instrument for easy calculation of yarn lengths when crimp wave amplitudes and wavelengths are known.
Crimp
Plain weave
Cite
Citations (12)
An investigation of the formation of crimp on jute fibers by the action of alkali is presented. Jute fiber-like strands are treated with various concentrations of NaOH under various conditions of temperature and time. As the result of the treatment, crimp is formed on some of the samples prepared. The measurements of crimp are carried out by a method developed by this Institute for single fibers which is adapted to the jute. The crimp diameter, the crimp ratio, the extension, and the wave number are quantitatively determined for the various jute samples as a function of the load applied to the fiber. An uncrimping energy of extension which sums up the extension over the range of loads used is measured. No crimp is formed at NaOH concentrations lower than 6%. At higher concentrations the crimp parameters increase to maximum values at 9% alkali, and thereafter decrease to constant levels. The crimp is formed after 0.5 hr. of treatment. The optimum temperature for the formation of the crimp is around 2° C. With increase in temperatures the values of the crimp parameters decrease, and at 40° C. no crimp is observed.
Crimp
Cite
Citations (19)
Wool fibres are subjected to severe mechanical actions during the worsted-spinning process, especially on a high-speed system. The loss of crimp and crimp recovery of single wool fibres are examined by measuring the crimp shrinkage of single fibres and the bulkiness of fibre bundles sampled at various stages in a commonly used worsted-spinning system. It is found that the crimp and crimp recovery of single fibres gradually decrease with progress through the spinning system, the reduction being particularly noticeable during carding. Fibre bundles with a high crimp level showed greater bulkiness.
Crimp
Worsted
Carding
Shrinkage
Cite
Citations (6)
Tensile and impact properties of compression molded unsaturated polyester/jute composites were investigated as a function of fiber content and orientation. Both unidirectional fiber composites with 0-50% weight fiber content and a randomly distributed short-fiber composite with 30% w/w were manufactured. The unidirectional composites were tested along and transversally to the fiber axis. Higher values for all mechanical properties were obtained when long-fiber oriented composites were tested along the fiber axis, even at low fiber content (10% w/w). The tensile behavior of the unidirectional composites qualitatively followed the theoretical isostrain and isostress behaviors, when the tests were conducted along and perpendicular to the fiber axis, respectively. The tensile properties of the composites tested perpendicular to the fiber were dominated by the strain at the fiber-matrix interface. Properties for randomly distributed short-fiber composites were found to be intermediate between those obtained with long-fiber oriented composites with the same fiber load tested along and across the fiber direction.
Cite
Citations (72)
The crimp shape and crimp elasticity characters of the PET/PTT monofilaments and multifila-ments under different tension and temperature were analyzed.As the tension of the heat treatment rose,the crimp frequency and the crimp radius of the monofilament went down,the crimp elongation rate went down,the crimp recovery rate and the crimp modulus of the monofilament and multifilament went up.As the temperature of the heat treatment rose,the crimp frequency increased and the crimp radius decreased.And the crimp elongation decreased,the crimp recovery rate and the crimp modulus of the monofilament and multifilament increased.When the temperature was 100～120 ℃ and the tension was little,the crimp elasticity of the PET/PTT monofilaments and multifilaments were better.
Crimp
Elongation
Elasticity
Tension (geology)
Cite
Citations (0)
The crimp parameters of twelve varieties of cotton, representing a wide range of grades, were measured. It was found that these cottons can be characterized by their crimp parameters. Relationships between crimp diameters and loads were found to show some typical behavior of cotton. Curves of crimp diameters against stresses, drawn from the results of these measurements, may be used for predicting crimp diameters of other cottons with known fiber diameters. It was found that the finer cotton grades are associated with lower crimp parameters and vice versa. The same was also found for the cottons with lower staple fibers. Also, the higher the tenacity, the lower the mean crimp diameter of the cotton.
Crimp
Tenacity (mineralogy)
Cite
Citations (4)
The crimp parameters of merino-wool fibres, i.e., the uncrimping energy and stress, decrease with an increase in relative humidity from 5.14 × 103 g cm/cm3 and 0.149 × 106 g/cm2 at 0% r.h. to 0.37 × 103 g cm/cm3 and 0.021 × 106 g/cm2 at 100% r.h., i.e., decreases of 93 and 86%, respectively. The decrease in the uncrimping parameters is linearly related to the increase in the ‘bound’ or ‘localized’ water up to the solution region of the wool-water isotherm. In the solution region, the crimp parameters appear to be associated with the ‘loose’ water. It is suggested that the contribution of the matrix phase of the fibre (crimp A) to the over-all crimp decreases with an increase in relative humidity until in water the main crimp is related to the microfibrillar phase (crimp B). The value of the drying uncrimping stress measured in this study, i.e., 1.25 × 108 dyn/cm2 is close to the value of 1.63 × 108 dyn/cm2 obtained previously for the ‘hygrostress’ at zero elongation, which indicates a parallelism between the two phenomena.
Crimp
Elongation
Breaking strength
Cite
Citations (1)
Abstract The objective of this paper is to analyse the correlation between crimp parameters and the effect of crimps on yarn strength and hairiness. Crimp is an essential property for natural and man-made fibres. Crimps always form with different parameters as they are very much irregular in size and shape. So, if the crimps are regular in size and shape, the end products like yarn and fabric properties will improve. Jute is a natural fibre with no natural crimp. In this research work, the gear crimping method was used as a mechanical crimping system to impart a regular size and shape of crimps into jute sliver. As a result, crimp parameters like the crimp length and crimp angle become uniform, and it is then easy to measure them. Results also showed that the crimp length is directly proportional and the crimp angle is reversely proportional to the number of crimps per unit length, and they are highly correlated. It was also shown that crimp and crimp parameters also affect the yarn strength and hairiness. In conclusion, it is revealed that with an increase in the number of crimps, the yarn strength was increased and hairiness was decreased.
Crimp
Breaking strength
Cite
Citations (1)
Merino wools from South Africa obtained from stud flocks were classified into visual crimp types, keeping in mind the way the crimp appeared to the practical wool judge. Wool samples were taken from 134 sheep from stud flocks. All but 18 were rams and ranged in age from lambs to very old sheep. Staple length and number of crimps per inch were measured for each sample, and the Quality number was obtained from the Duerden scale (Duerden 1929). The number of crimps per 5 cm of length was measured on the wool staples, and a visual estimate of the degree of crimp development was made using five different descriptive terms: Bold, Excellent, Average, Poor, and Straight. Representative sub-samples were mounted and then projected at a magnification of ten times, and the width and depth of crimp was read in millimetres. The ratio of width to depth was calculated by dividing the former by the latter. The measurements obtained were arranged by width—depth ratio and corresponded very closely to the visual classes. The visual crimp types of the wools from these stud Merino sheep corresponded closely with the width—depth ratio of the crimp with the coarser fleeces showing the bold crimp in the ratio of 3.000 or less. The depth of crimp has more influence on the crimp type than the width. Based on these measurements, the following table of crimp types can be set up: Crimp Type Wave Length-to-Depth Ratio Bold 3.000 or less and 56s Quality Excellent 3.000 or less and 58s or finer Average 3.001 to 4.000 Poor 4.001 to 5.000 Straight over 5.000
Crimp
Flock
Cite
Citations (0)