Investigation on the thermodynamical properties of some natural silk fibres with various physical methods

Bora, Mohendra Nath; Baruah, G.C.; Talukdar, Chitralekha

doi:10.1016/0040-6031(93)80441-c

Cited by 13 publications

(7 citation statements)

References 9 publications

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“…Crystallographic, thermodynamic, and hygroscopic studies of some major plant fibers such as cotton, flax, jute, ramie, etc. have been carried out by several investigators [3]. But investigations on thermophysical properties of plant fibers that are available in North-East India have not yet been carried out.…”

Section: Introductionmentioning

confidence: 98%

Investigations on Structural Characteristics, Thermal Stability, and Hygroscopicity of Sisal Fibers at Elevated Temperatures

Saikia¹

2008

Int J Thermophys

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An effort has been made to study the thermophysical properties of sisal plant fiber available in North-East India in the temperature range from 310 K to 760 K. The effect of heat on the structural characteristics of the fiber using X-ray diffraction and the chemical behavior by the infrared (IR) technique has been examined. Thermodynamic studies of the fiber have been carried out using thermogravimetric (TG), derivative TG (DTG), and differential scanning calorimetric methods. The hygroscopic properties of the fiber have been investigated in the temperature range from 310 K to 430 K at different relative air humidities using an ordinary gravimetric analysis. The interplanar spacings of the sample heated to 370 K remained same with respect to their normal values, but the degree of crystallinity and crystallite sizes increased slightly. The degree of crystallinity of the sample heated to 450 K is decreased by 10.32 % from its normal value, and the corresponding interplanar spacings and crystallite sizes are decreased by a small amount. A sample heated to 530 K shows transformation of the fiber's crystalline structure to an amorphous state. The fiber shows thermal stability up to 500 K and follows two different closely related thermal decomposition processes in the temperature range of approximately 500 K to 630 K. Tests performed in oxygen can lead to combustion of the fibers in the temperature range of approximately 710 K to 720 K. The IR study of the sample heated at temperatures from 370 K to 600 K provides meaningful data to ascertain decomposition of the native structure of the fibers. The hygroscopicity of the fiber under heated conditions is less with respect to the value under ambient conditions. The saturation limit of moisture absorption of the fiber per gram varies and depends on the source as well as pretreatment of the sample.

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Section: Introductionmentioning

confidence: 98%

Investigations on Structural Characteristics, Thermal Stability, and Hygroscopicity of Sisal Fibers at Elevated Temperatures

Saikia¹

2008

Int J Thermophys

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“…They reported a single endothermic peak at 319 o C under the pressure of 1.0 kg/cm 2 . When the nitrogen pressure was increased to 61 kg/cm 2 , two endothermic peaks were observed, one at 300 o C and the other at 326 o C. Talukdar et al (1991) and Bora et al (1993) have studied the three Indian varieties of silk fibres, mulberry, muga and eri by DTA and TGA. The DTA curves exhibited endothermic peaks at about 93 o C for all the three silk fibres, which were followed by an exothermic peak at around 312 o C for mulberry and muga and about 315 o C for eri.…”

Section: Introductionmentioning

confidence: 96%

Thermal Behaviour of Silk

K¹,

Sen

2007

Research Journal of Textile and Apparel

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If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. ABSTRACTSilk is a natural protein fibre. It is the only natural fibre available in continuous filament form. Earlier research studies on physical structure and mechanical properties of silk have indicated that the physical and chemical architecture varies between different varieties of silk and a substantial variation of these properties was observed within the cocoon. The amino acid composition and even the dyeing behaviour are different in different silk. Silk is considered as a non-thermoplastic fibre and is generally not expected to undergo significant morphological changes as a result of thermal shrinkage like synthetic fibres, viz., polyester and nylon. Needless to mention, silk fibres do undergo several kinds of heat treatments either in dry or wet state in the course of textile processing. Hence, an attempt has been made in this paper to deal with the response of different silk varieties (mulberry and non-mulberry) to thermal inputs. Five varieties of silk, two mulberry (bivoltine and crossbreed) and three non-mulberry (tasar, muga and eri) were subject to thermal treatments using TGA and DTA techniques. It was found that both mulberry and non-mulberry varieties behave differently to thermal inputs. Non-mulberry varieties show lower weight loss of 35-37% at 400 o C as compared to about 41-44% for mulberry varieties. They also exhibit a higher decomposition temperature. Interestingly, an additional transition at around 290 o C is clearly observed with all the nonmulberry silks. The DTA results indicate higher stability of non-mulberry silks towards thermal treatments.

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“…These changes corresponded to the crystalline regions as per the treatment of Goldanski et al 18 The molecular chains in cotton fibers take ordered arrangement and somewhat stable in the presence of water. 8 Because water molecules are present in the amorphous regions, as the removal of water molecule starts, the strain on the crystalline regions will be withdrawn, 28 and the chains get some freedom to rearrange. This rearrangement may give rise to larger size crystalline defects, as such an increase in 2 is expected.…”

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confidence: 99%

Thermally induced microstructural changes in cotton fibers: A free‐volume study

Ranganathaiah

2002

J of Applied Polymer Sci

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I measured positron lifetime in natural polymer-cotton fibers as a function of isochronal annealing temperature in the range 27-290°C. The variations in the positron results indicated structural changes occurring in the cotton fibers and determined the glass-transition temperature as 80°C. Activation energies were measured separately for the crystalline and amorphous regions, indicating the versatility of the technique. These values were close to the OOH bond dissociation energy, suggesting OOH bond dissociation, the most probable process occurring under thermal treatment. As an extension of the positron results, the molecular weight of the cotton fibers was determined to be 1,200,000 based on free volume, which was within the range suggested for cotton. There seemed to be an indication that crosslinking changed the spiral structure of cotton fibers to the network type. However, this needs to be validated by other measurements.

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Investigation on the thermodynamical properties of some natural silk fibres with various physical methods

Cited by 13 publications

References 9 publications

Investigations on Structural Characteristics, Thermal Stability, and Hygroscopicity of Sisal Fibers at Elevated Temperatures

Investigations on Structural Characteristics, Thermal Stability, and Hygroscopicity of Sisal Fibers at Elevated Temperatures

Thermal Behaviour of Silk

Thermally induced microstructural changes in cotton fibers: A free‐volume study

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