Journal of Fiber Bioengineering and Informatics
 
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JFBI -> 2010, Volume 3 Issue 3, 15 December 2010  
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Table of Content - JFBI 3.3
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JFBI. 2010, 3 (3): -no page.   DOI: no doi
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Table of Content - JFBI 3.3
Benchmarking Functionality of Historical Cold Weather Clothing: Robert F. Scott, Roald Amundsen, George Mallory
George Havenith
JFBI. 2010, 3 (3): 121-129.   DOI: 10.3993/jfbi12201001
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Replica clothing as worn by Robert F. Scott and Roald Amundsen in their race to be the first on the South Pole and by George Mallory in his ascent of Everest was tested for thermal insulative properties. These were benchmarked against modern day explorer clothing. Results are discussed in terms of insulation, insulation per weight, and wind protection. Further the effects of clothing on energy consumption were considered as well as the effect of altitude on insulation and energy consumption. The biggest advantage of modern clothing seems to be its lower weight. Scott's clothing resulted in extra energy usage for the wearers and provided less insulation than Amundsen's, though sufficient while active. The Mallory clothing had a low energy requirement due to the incorporation of 'lippery' silk layers. Its insulation would have been sufficient down to -30oC in low wind. If wind were to increase, the clothing would however not have provided the required insulation.
Analysis of Structure and Bending Behaviour of Quasi-Three-Dimensional Spacer Fabric Composite by Three-point Bending Tests
Zhao-Qun Du;Wei-Dong Yu;Hui Mao;Hua Shen;Xu-Chun Zhou;Gang Zheng
JFBI. 2010, 3 (3): 130-136.   DOI: 10.3993/jfbi12201002
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Glass-fiber fabric composites are widely used in applications, which are largely determined by the bending behaviour of fabric composites in through-thickness direction. In this work we have selected three types of quasi three spacer fabric made of glass fibres to analyze their structure and conduct bending experiments. The surface morphology in up, back and side views, as well as weaving/knitting structure were also observed. It exhibited that there existed much static atmosphere within fabric composite for a high porous structure. Moreover, the three-points bending properties were also measured by Instron tester. The bending load and deflection curve of fabric composite were obtained. The Typical Bending Stress and Strain Curves were calculated and studied for biaxial spacer weft-knitted fabric (named as sample #1), tuck stitch spacer warp-knitted fabric ( sample #2) and spacer woven fabric composite (sample #3). The testing results show that sample #1 had the highest indexes in bending stiffness, maximum bending stress and maximum bending load, followed by Samples #2 and #3. This can be attributed to the yarn’s orientation in fabric composite, i.e., the yarn’s crimp shape in thickness direction.
Analysis of Electrospun Nylon 6 Nanofibrous Membrane as Filters
Gui-Bo Yin
JFBI. 2010, 3 (3): 137-141.   DOI: 10.3993/jfbi12201003
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In this work, nylon 6 was firstly dissolved in 98% formic acid with the concentration of 13wt%, and then electrospun to obtain nanofibrous membranes. The morphology of the electrospun nylon 6 nanofibrous membranes was observed by scanning electron microscopy (SEM), the filtration efficiency and the mechanical properties were also examined. The results show that the average diameter of electrospun nylon 6 fiber was 217 nm, the surface average pore diameter was 234 nm, the thickness was 31 to 60 μm, the breaking tenacity was up to 8.06 Mpa and the elongation at break reached 52.8%; when the polyester fabric substrate was covered with the electrospun nylon 6 nanofiber membrane with the density of 1.25g/m2, at the airflow speed of 2.83l/min, the separation for 1μm, 0.5μm 0.3μm particles was 92.16%, 89.66%, 87.38%, respectively. In comparison, the fabric substrate just gave 9.92% separation for 1μm particles and had no filtration effect for 0.5μm and 0.3μm particles. The separation efficiency was improved by using a thicker electrospun membrane with the density of 2.5g/m2, the filtration efficiency could reach 97.03%, 96.23%, 95.65% for 1μm, 0.5μm 0.3μm particles repectively, but the permeability did not increase significantly. The excellent filtration performance, combined with a simple production process, suggested tremendous potential application as high-precision filter materials.
Synthesis of Poly(aryl ether ketone)s with Fluoro-substituted Benzene Side Chain
Juan Xie;Wei-Ya Peng;Guang Li;Jian-Ming Jiang
JFBI. 2010, 3 (3): 142-147.   DOI: 10.3993/jfbi12201004
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New bisphenol monomers, (4-fluoro)phenylhydroquinone and (3,4-bifluoro) phenylhydroquinone, were prepared in a two-step synthesis. Poly(aryl ether ketone)s were derived from these bisphenols via a nucleophilic aromatic substitution polycondensation with 4,4’-Difluorobenzophenone. The polycondensation proceeded quantitatively in N,N-dimethyl acetamide (DMAc) in the presence of anhydrous potassium carbonate and afforded the polymers with inherent viscosities of 0.50 and 0.92 dL/g. The glass transition temperatures were 151°C and 159°C respectively. The polymers also had high thermal decomposition temperatures and the temperatures of 5% weight loss were all above 527°C and the 10% weight loss were above 587°C in nitrogen atmosphere. There were no melting endotherms that were observed on DSC traces, which indicated that the copolymers were amorphous, and the amorphous structures were further confirmed by wide-angle X-ray diffraction. The polymers’ solubility was improved by the introduction of bulky pendant groups and all of them exhibited good solubility in some common solvents, such as NMP, DMF, DMSO, CH2Cl2, THF, CHCl3, etc. Transparent, strong, and flexible films were formed by the DMAc solutions of the polymers, with tensile strengths of 98.3 MPa, 95.2 MPa, Young’s moduli of 2.74 GPa, 3.06GPa, and elongation at break of 27%, 32%. The dielectric constants at 1 MHz of the polymers were 2.82 and 2.75.
Dyeing of Modal fiber in Supercritical Carbon Dioxide Using Disperse Dye C.I.(Color Index) Disperse Yellow 54
Da-Wei Gao;Quan Feng;Qu-Fu Wei;Lai-jiu Zheng
JFBI. 2010, 3 (3): 148-152.   DOI: 10.3993/jfbi12201005
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In this work, C.I.Dispersed Yellow 54 Modal fibers were dyed in supercritical carbon dioxide, and dyeing process was investigated and optimized. The key parameters including dye dosage, temperature, pressure and time of dyeing process were discussed both theoretically and experimentally. The degree of crystallinity and strength of the fibers were affected by fiber modification and dyeing. The final results obtained from this experiment indicated that only 20min was required to reach the equilibrium condition in supercritical carbon dioxide, and the dye yield increased with the increase in temperature. The dye-uptake increased along with the increase of pressure, however when the pressure was extended up to 18Mpa, the dye-uptake decreased slowly. The optimized conditions include winding of fibers around dyeing axis with the combination of different CO2 inlets, dyeing temperature at 100℃, pressure at 18MPa and time 20min.
Performance Analysis and Function Simulation of Protective Clothing Exposed to Electromagnetic Radiation
Li-Li Zhang;Yan Chen
JFBI. 2010, 3 (3): 153-158.   DOI: 10.3993/jfbi12201006
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Based on analyzing the performance of clothing when exposed to electromagnetic radiation, the electromagnetic simulation software (Ansoft HFSS) is used to establish electromagnetic model for abdominal cavity of human body, which can be applied to simulate the specific absorption rate (SAR) of the abdominal cavity under irradiation of electromagnetic waves. The SAR of the abdominal cavity with or without protective clothing and with different clothing has been compared, and the differences of electromagnetic protective performance between materials and clothing made of these materials are also discussed. The results show that the SAR of the abdominal cavity is larger when the radiation source frequency increases over a range of 300MHz to 900MHz .While at the same frequency of radiation sources, the protective performance of different clothing materials is related to their electrical characteristic parameters and protection patterns, and simply using the shielding effectiveness (SE) of clothing materials to illustrate the protective performance of clothing is relatively unilateral. Visualization of the electromagnetic protective performance of clothing can be preliminary achieved, and results of this research can also be applied to improve the electromagnetic protective performance of clothing during the processes of design and manufacture to ensure health and safety of the people.
Simulation of Number of Fibres in Roll Drafting Process
Guang-Song Yan*;Yu-Heng Su
JFBI. 2010, 3 (3): 159-162.   DOI: 10.3993/jfbi12201007
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Roll drafting is the key part of yarn manufacturing in ring spinning. Because of the fibre length distribution and the accelerated points of fibres in the drafting zone, the drafted strand usually tends to become uneven in terms of its linear density. The reported study mostly focuses on the accelerated points of fibre ends in the drafting zone, and also tries to find out the relation of the changing accelerated points and the irregularity of the drafted yarn. This approach investigates the role of the accelerated points, giving a parabolic-type probabilistic density function to fit the accelerated points of the floating fibres. Therefore, the stochastic simulation of the fibres in the drafting zone is conducted. The simulation process starts from a random fiber bundle nipped by the back roller, and then generates the accelerated point of each fibre by Mont Carlo method. For the given gauge distance and drafting ratio, any strand with a certain fibre length distribution can be simulated in the drafting system. The simulated curve of the number of fibres in the profile of the strand is given with different drafting parameters, which describes the attenuation of the strand in drafting. The results will help us to understand the drafting process and give a method of predicting yarn irregularity from fibre length distribution and drafting parameters.
Comparison and Analysis of Thermal Degradation Process of Aramid Fibers (Kevlar 49 and Nomex)
Hong-Ting Zhang
JFBI. 2010, 3 (3): 163-167.   DOI: 10.3993/jfbi12201008
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High performance fibers, such as polymer material, have extensive applications in aerospace, and high temperature environment. When these fibers were used in such high temperature, these would be subjected to degradation. To know and evaluate the thermal degradation process of materials under thermal environment, effective characterization and research methods must be adopted. In this paper, the thermal degradation processes of aramid fibers were studied by TGA-DTA/FT-IR. The experimental results show that aramid fibers (Kevlar 49, Nomex) have similar thermal stability, but their thermal degradation process and temperatures are different. Kevlar 49 fiber shows higher degradation temperature as a copolymer of para-aramid, and its initial degradation temperature is 548.1℃ in air. It can also be found that the Nomex fiber has a lower thermal degradation temperature and its initial degradation temperature is 423.7℃ in air. Ascending the temperature to 800℃, the two kinds of fibers loose all mass in air. We can get the wave number, absorbance time and three-dimensional images during the heating process by TGA-DTA/FT-IR tests. According to TG curves, the infrared spectra of decomposition products can be obtained and analyzed. The thermal decomposition process can be comprehensively discussed by the infrared spectra of decomposition products.
Theoretical Analysis and Prediction of Overfeed Sewing Shrinkage of Wool-type Fabrics
Tong-Hong Xu;Ping Gu
JFBI. 2010, 3 (3): 168-173.   DOI: 10.3993/jfbi12201009
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Overfeed is referred to two pieces of fabrics of different lengths being joined together with a thread by sewing processing. In overfeed sewing, the differences in mechanical properties of fabrics are vital factors contributing to the shrinkage of the finished fabric. Based on theory of material mechanics, the relationship model between overfeed sewing shrinkage and mechanical properties including bending modulus of the long fabric, stretch coefficient of the short fabric and the overfeeding quantity was established in this paper, and experiments were carried out to verify the relationship model. The obtained results indicated a good linear correlation between the calculated values of the model and the actual tested values. This model can provide a new method for predicting overfeed sewing shrinkage of wool-type fabric.
The Effect of Shearing Force that Influences Structural Transitions in Silk Fibroin
Yu Liu;Ying-Dong Cheng;Si-Yong Xiong;Peng-Ju Li;Yan-Qiong Wei;Ming-Zhong Li
JFBI. 2010, 3 (3): 174-180.   DOI: 10.3993/jfbi12201010
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Silk hydrogel has been utilized to deliver drug and growth factor and replace tissue. Therefore, exploring the structural changes of silk fibroin for variety of applications has attracted public concern. It has been reported that gel transition is influenced by temperature, pH, and shearing force. In this paper, we have studied the effect of shearing force that influences silk fibroin structural transitions. After stirring the silk fibroin solution at various shearing rates, the gelation time was observed. To investigate the effect of shearing force during the process, the molecular conformation of gel was investigated by CD, XRD, FT-IR and Raman spectroscopy. It was found that shearing force accelerated the gel rate, and with the increase of rate, gelation time decreased. The rate of 150r/min was more effective to promote gelation. β-sheet structure was formed by the shearing force, which was observed by X-ray diffraction. The crystallinity was increased effectively. After being lyophilized, the sample exhibited network and sponge-like structures. Remarkable changes in porosity were observed after using different shearing rates. It was observed that the higher the shearing rate, the lesser the pores formed.

ISSN 1940-8676
JFBI is Ei Indexed Journal
Editor-in-Chief: Prof. Yi Li
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