The Effect of Drawing Process on the Properties of Split-Film PTFE Fiber

2012 ◽  
Vol 602-604 ◽  
pp. 1946-1950 ◽  
Author(s):  
Xin Min Hao ◽  
Yuan Yang ◽  
Bin Xiang Huang ◽  
Lei Huang ◽  
Guo Jun Zhang
Keyword(s):  
Mechanical Properties ◽  
Draw Ratio ◽  
Breaking Strength ◽  
Three Dimensional ◽  
Drawing Process ◽  
Heat Setting ◽  
Elongation At Break ◽  
Ptfe Membrane ◽  
Hot Drawing ◽  
Temperature Controlled

From PTFE baseband prepared by three-dimensional drawing, after the processing of different temperature and time. And then by twisting, hot drawing and heat setting, the PTFE filament was prepared in appropriate tension conditions. The surface morphology of the resulting filaments was observed by SEM, the result shows that the uniformity of the PTFE membrane has been improved by using three-dimensional drawing process, hot drawing processes had a great effect upon the breaking strength and elongation at break of PTFE fibers. In order to keep ensure reasonable mechanical properties, the draw ratio in the range of 20 to 50 times to adjust the temperature controlled at 150°C to 300 °C.

Preparation of Polyamide 5,6 (PA56) Fibers and its Mechanical Properties

2014 ◽  
Vol 937 ◽  
pp. 86-91 ◽  
Author(s):  
Yassir A. Eltahir ◽  
Haroon A.M. Saeed ◽  
Yu Min Xia ◽  
Yi Min Wang
Keyword(s):  
Mechanical Properties ◽  
Molecular Orientation ◽  
Draw Ratio ◽  
Melt Spinning ◽  
Tensile Modulus ◽  
Fiber Axis ◽  
Elongation At Break ◽  
Significant Difference ◽  
Hot Drawing ◽  
Melt Spinning Technique

Polyamide 5,6 (PA56) fibers were successfully prepared by melt-spinning technique. PA56 fibers were subjected to hot drawing process at different draw ratio and temperature. The effect of the drawing conditions on their mechanical properties such as tenacity, tensile modulus and breaking elongation were investigated by means of tensile test measurements. The results revealed that the tenacity and tensile modulus were found to be increased, while the elongation at break decreased with the draw ratio. The improvements of the mechanical properties could be attributed to the enhanced of the molecular orientation along the fiber axis and an increase in crystallinity. On the other hand, the PA56 fibers mechanical properties do not show significant difference with the drawing temperatures.

Mechanochemical Devulcanization of Vulcanized Gum Natural Rubber

2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Three Dimensional ◽  
Elongation At Break ◽  
Tear Strength ◽  
Vulcanized Rubber ◽  
Dimensional Network ◽  
Polymeric Chains ◽  
Cure Time

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.

Study on the Crystallization Behavior of PAN Fibers during Hot-Drawing Process in Supercritical Carbon Dioxide Fluid with Different Strain

2020 ◽  
Vol 976 ◽  
pp. 84-89
Author(s):  
Meng Meng Qiao ◽  
Hai Juan Kong ◽  
Xiao Ma Ding ◽  
Zhi Feng Hu ◽  
Mu Huo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Carbon Fibers ◽  
Crystallization Behavior ◽  
Strength Analysis ◽  
Drawing Process ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

Hot-drawing of polyacrylonitrile (PAN) fibers is an important step in the production of carbon fibers. In this article, we investigated the effect of strain on the crystallization behavior and mechanical properties of PAN fibers treated in supercritical carbon dioxide (Sc-CO2) fluid. We mainly used the methods of X-ray diffraction (XRD), monofilament strength analysis and differential scanning calorimeter (DSC) to study the crystallization behavior, mechanical properties and thermal behavior of PAN fibers during hot-drawing process. The experimental results showed that the crystallinity and mechanical properties of PAN fibers both increased a lot under the action of strain during hot-drawing in Sc-CO2 fluid. This provides an important method for preparation of higher performance PAN precursor for PAN-based carbon fibers.

Biomimetic Hemocompatible Nanofibrous Scaffolds as Potential Small-Diameter Blood Vessels by Bilayering Electrospun Technique

2011 ◽  
Vol 306-307 ◽  
pp. 1627-1630 ◽  
Author(s):  
He Yun Wang ◽  
Ya Kai Feng ◽  
Hai Yang Zhao ◽  
Ruo Fang Xiao ◽  
Jin Tang Guo
Keyword(s):  
Mechanical Properties ◽  
Blood Vessel ◽  
Breaking Strength ◽  
Small Diameter ◽  
Matrix Structure ◽  
Complex Matrix ◽  
Elongation At Break ◽  
Artificial Blood ◽  
Nanofibrous Scaffolds ◽  
Morphology And Mechanical Properties

In this paper, we prepared a scaffold composed of a polyurethane (PU) fibrous outside-layer and a gelatin-heparin fibrous inner-layer with mimicking morphology and mechanical properties of a native blood vessel by sequential bilayering electrospinning technology on a rotating mandrel-type collector. The scaffolds achieved the appropriate breaking strength (3.7 ± 0.13 MPa) and elongation at break (110 ± 8%). When the scaffolds were immersed in water for 1 h, the breaking strength decreased slightly to 2.2 ± 0.3 MPa, but the elongation at break increased up to 145 ± 21%. Heparin was released from the scaffolds at substantially uniform rate until the 9th day. The scaffolds were expected to mimic the complex matrix structure of native arteries, and had good hemocompatibility as an artificial blood vessel owing to the heparin release.

Effect of Wet Post-Drawn on Structures and Properties of PA6/MWNTs Nanofiber Filaments

2011 ◽  
Vol 175-176 ◽  
pp. 90-94 ◽  
Author(s):  
Yang Liu ◽  
Jie Li ◽  
Zhi Juan Pan
Keyword(s):  
Mechanical Properties ◽  
Draw Ratio ◽  
Breaking Strength ◽  
Control Sample ◽  
The Poor ◽  
Structures And Properties ◽  
Initial Modulus ◽  
The World ◽  
Degree Of Orientation ◽  
Nonwoven Fiber

Electrospining technique is one of the hotest topics all over the world. The main form of the electrospun products is generally nonwoven fiber web with the poor mechanical properties. Consecutive PA6/MWNTs nanofiber filaments were successfully fabricated by an improved electrospining method. Peregal O was used as the bath to post-draw the as-spun filaments and the effects of draw ratio on their structures and properties were studied. The results show that with the increase of the draw ratio, the diameters of filament and fiber decrease; while the degree of orientation arrangement and crystallinity of the fibers is obviously improved and the breaking strength and initial modulus of the filaments increase. As the maximum draw ratio reaches 1.7, the breaking strength and initial modulus of the filament are 2.64 times and 4.2 times as compared to those of the control sample respectively.

scholarly journals Preparation of CaCO3-SiO2 composite with core-shell structure and its application in silicone rubber

2015 ◽  
Vol 17 (4) ◽  
pp. 128-133 ◽  
Author(s):  
Chenglin Cui ◽  
Hao Ding ◽  
Li Cao ◽  
Daimei Chen
Keyword(s):  
Mechanical Properties ◽  
Silicone Rubber ◽  
Shell Structure ◽  
Breaking Strength ◽  
Core Shell ◽  
Elongation At Break ◽  
Chemistry Method ◽  
Core Shell Structure

Abstract A new CaCO3-SiO2 composite with core-shell structure was successfully prepared by mechano-chemistry method (MCM). SEM and FTIR indicated that SiO2 particles were homogeneously immobilized on the surface of CaCO3. The well dispersion of this CaCO3-SiO2 composite into silicone rubber can not only reduce the usage amount of SiO2, but also improve the mechanical properties of silicone rubber. By the calculation, the theoretical numbers of the SiO2 particles is about 10 times as large as that of CaCO3 particles in the CaCO3-SiO2 composite. Mixing CaCO3-SiO2 composite in silicone rubber can enhance the breaking strength of the silicone rubber about 18% as high as that when mixing the pure SiO2. And the elongation at break is about 14% less than that of adding the pure SiO2 sample.

Mechanical Properties of Cotton Yarns Mercerized in Liquid Ammonia and Sodium Hydroxide

1976 ◽  
Vol 46 (12) ◽  
pp. 872-879 ◽  
Author(s):  
M. L. Nelson ◽  
C. B. Hassenboehler ◽  
F. R. Andrews ◽  
A. R. Markezich
Keyword(s):  
Mechanical Properties ◽  
Sodium Hydroxide ◽  
Liquid Ammonia ◽  
Breaking Strength ◽  
Continuous Process ◽  
Elongation At Break ◽  
High Tension ◽  
Initial Modulus ◽  
Cotton Yarns ◽  
Length Changes

Yarns spun from high- and low-maturity cottons were mercerized in liquid ammonia in a continuous process, and in liquid ammonia and sodium hydroxide in skein form under various tensions. Both swelling agents produced similar changes in mechanical properties (breaking strength, tenacity, elongation-at-break, and initial modulus) under comparable conditions. Mercerization under high tension increased breaking strength and tenacity and decreased elongation-at-break. Slack mercerization in caustic resulted in elongations-at-break substantially higher than did ammonia treatment. A major difference between reagents was noted during treatment. When skeins were swollen slack and then restretched, much greater force was required to restretch ammonia-swollen skeins, and they could not be stretched as much as those that were caustic-swollen. Measurements of length changes in yarns during swelling, tensioning, and deswelling gave quantitative data to substantiate this observation. Differences in mechanism of swelling are discussed in relation to these findings.

The Influence of Dyeing & Finishing Process on Mechanical Properties of PU Filaments

2011 ◽  
Vol 332-334 ◽  
pp. 196-199
Author(s):  
Jian Ming Wang ◽  
Hong Bo Zhang
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
High Temperature ◽  
Breaking Strength ◽  
Heat Setting ◽  
Influence Of Temperature ◽  
Finishing Process ◽  
Elongation Percentage ◽  
Temperature Time ◽  
Strength Retention

Abstract. Several convert processes, e.g. Scouring, Bleaching, Heat setting, High temperature & high pressure dyeing (HTHPD), which might damage the breaking strength of PU filaments were examined in this research. The influence of temperature, time and elongation percentage in heat setting was discussed in particular. The experimental results show that the dominant processes which damage the PU filaments are heat setting and HTHPD. The breaking strength retention of PU filaments range between 51.74%-84.03%, 67.64%-74.67%, respectively after heat setting & HTHPD. The higher the elongation percentage, the lower the heat setting efficiency.

Study on Preparation and Properties of PA6/TiO2-GO Composites

2020 ◽  
Vol 1001 ◽  
pp. 224-228
Author(s):  
Dan Liu
Keyword(s):  
Mechanical Properties ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Breaking Strength ◽  
Degree Of Crystallinity ◽  
Methylene Blue Solution ◽  
Elongation At Break ◽  
Increasing Trend ◽  
Blue Solution ◽  
The Degree Of Crystallinity

In this paper, the effect of nanoTiO2 content on the thermal properties, mechanical properties, photocatalytic properties of PA6/TiO2-GO composites were investigated. The results indicated that the melting point of the composites decreased gradually with an increase of nanoTiO2 content, and the degree of crystallinity exhibited an increasing trend at first and then tended to decrease. Meanwhile, the breaking strength decreased gradually, whereas the elongation at break increased gradually. Moreover, the nanoTiO2 exhibited an increasing photocatalytic activity for degradation of the methylene blue solution. The incorporation of graphene oxide (GO) could effectively improve the photocatalytic effectiveness of nanoTiO2 by approximately 11%.

scholarly journals Effect of Different Pressures of Supercritical Carbon Dioxide on the Microstructure of PAN Fibers during the Hot-Drawing Process

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 403 ◽  
Author(s):  
Mengmeng Qiao ◽  
Haijuan Kong ◽  
Xiaoma Ding ◽  
Zhifeng Hu ◽  
Luwei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Strength Analysis ◽  
Drawing Process ◽  
X Ray ◽  
Degree Of Orientation ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

The hot-drawing process of polyacrylonitrile (PAN) fibers is an important step during the production of PAN-based carbon fibers. In this study, supercritical carbon dioxide (Sc-CO2) was used as one kind of media for thermal stretching of PAN fibers to study the effect of different pressures of Sc-CO2 on crystallinity, degree of orientation and mechanical property of PAN fibers during the hot-drawing process. The changes of microstructure and mechanical properties in the PAN fibers were investigated by wide-angle X-ray diffraction, small angle X-ray scattering and monofilament strength analysis. The results showed that as the pressure increased, the crystallinity and degree of orientation of PAN fibers increased. Furthermore, when the pressure was 10 MPa, the crystallinity increased from 69.78% to 79.99%, which was the maximum crystallinity among the different pressures. However, when the pressure was further increased, the crystallinity and degree of orientation of the fibers were reduced. The test results of the mechanical properties were consistent with the trends of crystallinity and degree of orientation, showing that when the pressure was 10 MPa, the tensile strength of the fibers increased from 4.59 cN·dtex−1 to 7.06 cN·dtex−1 and the modulus increased from 101.54 cN·dtex−1 to 129.55 cN·dtex−1.

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