Effect of annealing on crystal size in pure Mysore silk fibres

Somashekar, R.; Urs, Raj

doi:10.1007/bf02745093

Cited by 9 publications

(2 citation statements)

References 7 publications

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“…Silk-based reactions are very important for all possible chemical modifications of natural products. Much attention has been paid to the modification and utilisation of silk due to its good biodegradability and biocompatibility [1][2][3]. In recent years, the modifications and drying of some materials have been conducted under microwave irradiation conditions [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Microwave Irradiation on the Physical Properties and Structure of Silk Fibre

Zhao¹

2018

Fibres and Textiles in Eastern Europe

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Microwaves are high frequency radio waves which are capable of penetrating many materials and causing heat to be generated in the process. To investigate the effect of microwave irradiation on the physical properties as well as the chemical , surface morphological and fine structure of silk fabric, silk fabric was treated with microwave irradiation under a variety of conditions in terms of the power and time of microwave treatment. The breaking strength, elongation at break, and whiteness of the treated silk fabric in a wet state were investigated. The structures of the untreated and treated silk were investigated with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results show that the physical properties of the treated silk fabrics were changed with the microwave irradiation time. The chemical and surface morphological structure as well as the decomposition temperature and crystallinity of the treated silk were changed.

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Section: Introductionmentioning

confidence: 99%

Effect of Microwave Irradiation on the Physical Properties and Structure of Silk Fibre

Zhao¹

2018

Fibres and Textiles in Eastern Europe

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“…Improvement in the Gaq3 properties is crucial for its application in OLED and/or OSC devices. Various strategies were undertaken by researchers to enhance the physical behaviour of organic materials, namely thermal annealing process [10][11][12], in-situ controlled substrate temperature [13] and the use of different substrates [14]. Thermal evaporation under cold trap at different working temperatures and pressures was examined to fabricate crystalline Alq3 and Gaq3 nanostructures on silicon substrates [13,15].…”

Section: Introductionmentioning

confidence: 99%

Morphology Impact on the Absorption Behaviour of Post-Thermally Treated Tris(8-Hydroxyquinoline) Gallium Films

Muhammad

2015

ILCPA

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ABSTRACT. This work reports on the impact of surface morphology on the optical absorption of vacuum deposited tris(8-hydroxyquinoline) gallium (Gaq3) films. Morphological investigation was performed for films treated under nitrogen gas in the temperature range from 85 o C to 255 o C. The results of field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD) technique ascertained the formation of amorphous nanostructures. Considerable modification in the absorption behaviour of Gaq3 films was observed upon morphological changes. The results of these modifications were ascribed to the impact of morphological variations among the surface of Gaq3 films.

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Crystal size and minimum enthalpy of crossbreed silk fibers annealed at various temperatures

Somashekar

Urs²

1993

J of Applied Polymer Sci

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SYNOPSISWide-angle X-ray diffraction studies of crossbreed silk fibers and fibers annealed at various temperatures for different periods of time were carried out to evaluate the crystal size and lattice distortion parameters, as these determine the properties of silk fibers. Also, minimum enthalpy for the formation of these fibers has been estimated and compared. I NTRO DUCT10 NSilk, which is a fibrous protein, is one of the industrially important fibers. Wide-angle X-ray scattering studies (WAXS) by earlier investigators of silk fibers have shown that they are partially crystalline.' For a perfect crystal, the diffraction pattern would comprise of an array of very small spots. For silk fibers, the spots are made into arcs that are caused by two types of defects present in the silk fibers: first, the lattice distortion, and, second, the effect of the crystal size.' Using Fourier analysis of the scattered X-ray reflections, we determined the crystal size and lattice distortion parameters for (210) equatorial reflections of crossbreed silk fiber and the effect of annealing on these parameters has been studied. Also, we determined the minimum enthalpy for the formation of these fibers. Such studies have not been reported earlier except for determining the cell p a r a r n e t e r~~-~ and percentage of crystallinity6 for natural silk fibers.Both multiple-and single-order methods used to separate crystal size and distortion parameters are derived from the theory of Warren-Averbach7 utilizing the Fourier cosine coefficients of the intensity profile. Somashekar et al? and Hall and Somashekar' considered various aspects of multiple-and single- CCC 0021-8995/93/060949-04 order methods. Recently, we extended a single-profile method to natural polymers.1° THEORYThe intensity profile of the X-ray reflection from a partially crystalline sample like natural silk fibers is a function of the distribution of crystal sizes and of the lattice distortion g, and these are related through the Fourier coefficients A ( n ) to the profile intensity I ( S) by the equationHere, So is the value of S ( = sin B / h ) at the peak of the profile; d , the mean d-spacing of the lattice planes causing the reflection; and n , the harmonic number.The Fourier coefficients can be factorized into size As ( n ) and disorder coefficients Ad ( n ) :These are not normalized. By taking the exponential distribution function for crystal sizes, which gives fairly reliable results, lo we have the following relations for As( n ) :

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Effect of annealing on crystal size in pure Mysore silk fibres

Cited by 9 publications

References 7 publications

Effect of Microwave Irradiation on the Physical Properties and Structure of Silk Fibre

Effect of Microwave Irradiation on the Physical Properties and Structure of Silk Fibre

Morphology Impact on the Absorption Behaviour of Post-Thermally Treated Tris(8-Hydroxyquinoline) Gallium Films

Crystal size and minimum enthalpy of crossbreed silk fibers annealed at various temperatures

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