• Title/Summary/Keyword: crystallinity index

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Determination of crystallinity index of cellulose depending on sample preparation and analysis instruments (시료 조건 및 측정방법에 따른 셀룰로오스의 결정화도 평가)

  • Ahn, Jung-Eon;Youn, Hye-Jung;Joung, Yang-Jin;Kim, Tae-Young
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.44 no.4
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    • pp.43-50
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    • 2012
  • The crystallinity index is an important characteristic of cellulose. The crystallinity value is different depending on the adopted instrument. In this study, we determined a crystallinity index of cotton and wood celluloses using wide-angle X-ray scattering (WAXS), powder X-ray diffractometer (PXRD), and cross polarization/magic angle spinning solid-state $^{13}C$ nuclear magnetic resonance spectroscopy (CP/MAS solid-state $^{13}C$ NMR). The specimen was prepared in forms of powder, sheet and pallet. With the comparison of the obtained crystallinity indices of the cellulose, the effects of the analysis instrument, the sample preparation and analysis method were investigated. Among three instruments, the crystallinity indices by PXRD and NMR had a good relationship and reproducibility, and WAXS gave the crystallinity index with poor reproducibility. In the case of analysis methods of crystallinity indices, the Segal method showed higher value than that of the Ruland-Vonk method. We expect that this study would be applicable to evaluate the crystallinity index of various cellulose materials with accuracy and reproducibility.

Adsorption Characteristic of Endo I and Exo II Purified from Cellulase by Trichoderma viride on Celluloses with Different Crystallinity (결정성이 다른 셀룰로오스에 대한 Trichoderma viride속 Cellulase로부터 분리한 Endo I 및 II의 흡착특성)

  • 김동원;홍영관;장영훈;이재국
    • KSBB Journal
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    • v.13 no.2
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    • pp.162-167
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    • 1998
  • The adsorption behaviors of two major cellulase components, endo I and exo II, from Trichoderma viride were investigated using $\alpha$-celluloses with different correlation crystallinity index(Cc) as substrates. The adsorption of cellulase enzyme components was significantly affected by the reaction condition and the physicochemical properties of the cellulose. The $\alpha$-cellulose was hydrolyzed in the presence of cellulase for various periods. The correlation crystallinity index of $\alpha$-cellulose increased with increasing the hydrolysis time. The adsorption was apparently found to obey the first-order kinetics, and the adsorption activation energy(Ea) was calculated from the adsorption rate constant(ka). The value of adsorption rate constant for endo I was larger than that of exo II. This means that endo I are adsorbed more rapidly than exo II. With the increase in correlation crystallinity index, the values of the adsorption rate constants for endo I and exo II decreased, respectively. The activation energy for the adsorption of exo II on the cellulose also was larger than that of endo I. Also adsorption activation energy of endo I and exo II increased with an increase in the crystallinity of sample cellulose.

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Crystal Structure of Tension Wood by X-ray Diffraction Method (X 선(線) 회절법(回折法)에 의한 Tension Wood의 결정구조(結晶構造) 해석)

  • Lee, Won-Yong;Kim, Nam-Hun
    • Journal of the Korean Wood Science and Technology
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    • v.21 no.4
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    • pp.73-78
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    • 1993
  • Crystal structure of tension, opposite and lateral wood of Platanus orientalis L. were analysed in some aspects of crystallinity index, crystallite size, d-spacing of (200) and (004), and integrated intensity ratios with X-ray diffraction method. Crystallinity index and crystallite width in tension wood appeared somewhat larger than opposite or lateral wood. However, d-spacing and integrated intensity ratios were nearly identical irrespective of tension, opposite, and lateral wood.

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Crystal Structures of the Vessel Elements and the Wood Fibers of Quercus variabilis BLUME (굴참나무재의 목섬유 및 도관 cellulose의 결정구조)

  • Kim, Nam-Hun;Lee, Woon-Yong
    • Journal of the Korean Wood Science and Technology
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    • v.21 no.1
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    • pp.15-20
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    • 1993
  • X-ray diffractograms of the vessel elements and the wood fibers of Quercus variabilis BLUME were recorded and resolved into characteristic reflections of cellulose I. Some differences were observed in the ratio of integrated intensity and crystallinity index between vessel elements and wood fibers. Present results suggest that cellulose crystal structure in the hardwood species was varied with the elements of wood.

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The Effect of Extraction Conditions and Film Side on the Molecular Conformation of Silk Sericin Film

  • Jo, Yoon Nam;Bae, Do Gyu;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.26 no.2
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    • pp.113-118
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    • 2013
  • In this study, silk sericin films were prepared using different extraction methods, and the molecular conformation of sericin was examined using Fourier-transform infrared spectroscopy with attenuated total reflection geometry. Additionally, the effect of the film side (air-facing side or plate-facing side) on the molecular conformation of the sericin films was investigated. Interestingly, the molecular conformation of the sericin film depended on the film side. The molecular conformation of air-facing side of the sericin film was significantly influenced by extraction solution and time. The ${\beta}$-sheet crystallization and the crystallinity index of the sericin film markedly increased with an increase in the extraction time in hot water. The order of the crystallinity indices for the sericin films obtained with different extraction solutions was as follows: citric acid solution > urea solution >> hot water. In contrast, no remarkable differences were observed in the molecular conformation of the plate-facing side of the sericin film after extraction in hot water for different time periods. Urea and citric acid solution extractions showed remarkably higher crystallinity indices for sericin than those obtained after hot water extraction. However, no significant differences were observed in the crystallinity index of sericin between urea and citric acid solution extraction in plate-facing side of the film.

Structural Characterization of Silk Fiber Treated with Calcium Nitrate (질산칼슘 처리 농도에 따른 수축견사의 구조특성)

  • 이광길;이용우
    • Journal of Sericultural and Entomological Science
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    • v.39 no.2
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    • pp.186-196
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    • 1997
  • The IR crystallinity index of Calcium nitrate treated silk fiber decreased proportionally to the concentration of calcium nitrate. A partial change of conformation was observed in the concentration of over 46.4-47.6% changing from $\beta$-sheet or to random coil in the crystalline region. This is in coincidence with the result of crystallinity index, which was started to be reduced in the concentration range of 46.4-47.6%. A same trend was observed for the X-ray order factor, birefringence, degree of orientation and surface structure. These structural parameters were remarkably changed on the treatment of silk fibers with concentration of 46.4-17, 6% calcium nitrate. Therefore, it seems that there exists a critical concentration of calcium nitrate in affection the structure and morphology of silk fibers. According to the examination of surface morphology, the fine stripe was observed in the direction of fiber axis at 46.4% concentration. However, the treated concentration was exceeded by 47.6%, the cracks were appeared severely on the fiber surface in the transverse direction as well as fiber axis direction. This result might be related to the tensile properties, specially a tenacity of silk fibers. As a result of quantitative analysis of a dilute acid hydrolysis, three different regions, which are known as a amorphous, semi-crystalline and crystalline region, could be obtained. The hydrolysis rate curves were different with various concentrations of treatment and the relative contents of each region could be calculated.

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Effect of Processing Conditions on the Homogeneity of Partially Degummed Silk Evaluated by FTIR Spectroscopy

  • Kim, Hyun Ju;Chung, Da Eun;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.26 no.1
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    • pp.54-60
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    • 2013
  • The partial degumming of silk has recently attracted researchers' attention because of its ability to produce silk textiles with new tactile properties, intermediate between the softness of fully degummed silk and the hardness of raw silk. However, it is difficult to obtain partially degummed silk in a homogenously degummed state due to the heterogeneous character of sericin removal. It is also difficult to examine the homogeneity of degumming. In the present study, Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR) geometry was used to evaluate the effect of processing conditions on the degumming of silk yarns. The crystallinity index, calculated from FTIR spectra, showed an increase with the degumming ratio. Therefore, the homogeneity of degumming could be evaluated by the variation of crystallinity index for 30 different spots in silk yarns. The homogeneity of degumming was influenced by the total degumming time, the content of surfactant, and the liquor rate. No effect was observed upon changing the number of degumming cycles at the same total degumming time.

Molecular conformation and crystallinity of white colored silkworm cocoons with different silkworm varieties

  • Park, Bo Kyung;Nho, Si Kab;Um, In Chul
    • International Journal of Industrial Entomology
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    • v.38 no.1
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    • pp.18-23
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    • 2019
  • Bombyx mori silkworm has many silkworm varieties and the structure and properties of silk can be varied depending on the silkworm variety. Therefore, the choice of proper silkworm variety can be an effective way to control and improve the performance of silk materials in biomedical and cosmetic applications. As a preliminary study, in the present study, thirty nine Bombyx mori silkworm cocoons were prepared and their molecular conformation and crystallinity were examined. Molecular conformation and the crystallinity of silkworm cocoons were different depending on the silkworm variety. Interestingly, the crystallinity index of outside of cocoon was different from that of inside of cocoon and the difference between the crystallinities of outside and inside of cocoon was varied depending on the silkworm variety. In this study, the silkworm variety cocoons were classified into three groups (Group 1, Group 2, and Group 3) based on the difference of crystallinities between outside and inside.

Conservation status assessment of archaeological bone from Fourier Transform Infrared Spectroscopy and histological Analysis (적외선 분광 분석과 조직 분석을 통한 출토 인골의 보존 상태 평가)

  • Lee, Jeongwon;Kim, Sue Hoon;Kim, Yun-Ji;Cho, Eun Min;Kang, Soyeong
    • 보존과학연구
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    • pp.87-98
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    • 2014
  • Fourier transform infrared spectroscopy(FTIR-ATR) was applied to chemical analysis for conservation status of 10 human bone remains from Joseon Dynasty. The result of crystallinity index (CI) is $4.25{\pm}0.78$, carbonate to carbonate ratio (C/C) is $0.91{\pm}0.04$ and cabonate content (C/P) is $0.19{\pm}0.06$. The higher histological index (HI) confirmed CI and C/P value was increased and C/C value was reduced. While C/C or C/P values analysis is possible. While DNA analysis can be extracted from the bone, C/C values are lower or C/P values are higher was found to the analysis is possible. Chemical assessment of FTIR and histological index consequence is expected to be applicable as a basis for comprehensive understanding of the conservation status excavated bones.

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