Effect of Heat Setting Methods on Structures and Properties of High Strength Polyvinyl Alcohol Fibre

2015 ◽  
Vol 815 ◽  
pp. 643-648
Author(s):  
Yin Zhu ◽  
Jiong Xin Zhao

The effect of heat setting methods on the structures and mechanical properties of high strength polyvinyl alcohol (PVA) fibre is studied in this article. The microstructure and mechanical properties of heat treated PVA fibre is investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and single fibre electronic tensile strength tester. Results show that the heat setting method with constant tension is a good heat setting method which can largely enhance the tensile strength of PVA fibre. During the heat setting process, the mechanical properties of PVA fibre are greatly affected by the temperature, tension and setting time. When the temperature is 220°C, tension is 5cN/dtex and setting time is 90sec, the tensile strength of PVA fibre increases from 12.0cN/dtex to 16.4cN/dtex in compare with the PVA fibre without heat setting

2016 ◽  
Vol 51 (14) ◽  
pp. 1971-1977 ◽  
Author(s):  
NH Noor Mohamed ◽  
Hitoshi Takagi ◽  
Antonio N Nakagaito

The mechanical properties of cellulose nanofiber-reinforced polyvinyl alcohol composite were studied. Neat polyvinyl alcohol films, cellulose nanofiber sheets, and their nanocomposites containing cellulose nanofiber weight ratios of 5, 15, 30, 40, 45, 50 and 80 wt% were fabricated. Heat treatment by hot pressing at 180℃ was conducted on the specimens to study its effect to the mechanical properties and the results were compared with the non heat-treated specimens. Morphology of the composites was studied by scanning electron microscopy and the mechanical properties were evaluated by means of tensile tests. The results showed that increase of cellulose nanofiber content from 5 wt% to 80 wt% has increased the tensile strength of the composites up to 180 MPa, with cellulose nanofiber content higher than 40 wt% yielding higher tensile strength. The heat-treated specimens exhibited higher tensile strength compared to those of untreated specimens.


2011 ◽  
Vol 335-336 ◽  
pp. 1477-1480
Author(s):  
Lu Wang ◽  
Chang Kun Ding ◽  
Hao Bo Shi ◽  
Bo Wen Cheng ◽  
Wu Qiong

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is biosynthetic aliphatic polyester with good biocompatibility and biodegradability. In this paper, PHBV biodegradable fibers were manufactured by melt-spinning, and the drawing procedure and heat setting of the fibers were applied. By X-ray diffraction, SEM and stress-strain measurements, the crystalline and mechanical properties of PHBV fibers were investigated. The results showed that β-form crystals were obtained in some PHBV fibers. Surface fibrillation phenomenon occurred in the oriented PHBV fibers. The tensile strength of PHBV fibers increased with increasing the draw ratio. The tensile strength of 10 times stretched PHBV fibers can reach 227 MPa.


2019 ◽  
Vol 7 (4.14) ◽  
pp. 392
Author(s):  
N. N.A. Basir ◽  
N. H. Mustafa ◽  
R. E. Ibrahim ◽  
R. Rosmamuhamadani ◽  
M. M. Mahat ◽  
...  

Aluminium based metal matrix composites (MMCs) have better properties and performance. They are commonly used in transport applications which require combinations of high strength and ductility. They are quite attractive due to their low density, capability to be strengthened by precipitation, good corrosion resistance, high thermal and electrical conductivity. Grain refinement plays a crucial role in improving characteristics and properties of aluminium-silicon (Al-Si) alloy. In this investigation, scandium (Sc) and strontium (Sr) elements were added to aluminium-silicon-titanium diboride (Al-Si-TiB2) alloy for refinement of grains. The compositions of 93 wt.% Al-Si, 6 wt.% TiB2, 0.5 wt.% Sc and 0.5 wt.% Sr were melted into induction furnace. Then the composites have been characterized on the mechanical properties and microstructure characterization. Instron tensile machine and vickers hardness tester were used to characterize the mechanical properties of the composite alloy. Microstructure and phase composition were characterized by Field Emission Scanning Electron Microscope (FESEM) and X-ray Diffraction (XRD). From the results obtained, addition of Sc and Sr, into Al-S-TiB2 improved the tensile strength and hardness of composite alloy. Results also showed that the inoculants addition able to enhance the refinement of grains and escalate the values of hardness and tensile strength of Al-Si-TiB2 composite. Mechanical properties related much on the microstructure as it can be seen that the addition of grain refiners produced much higher value of mechanical properties.  


2020 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Maria Clara Rozo Terreiro Seffrin ◽  
João Victor Toledo de Almeida de Souza ◽  
Maria Rosária Oliveira ◽  
Erika Peterson Gonçalves

ResumoO gesso é um material de construção amplamente utilizado devido à sua leveza e baixo custo, mas se torna um passivo ambiental, pois os resíduos gerados na construção e demolição de edifícios são descartados incorretamente e podem causar grandes danos ao solo e às águas subterrâneas. Sua reciclagem tem sido extensivamente estudada, mas fatores ambientais e de gerenciamento no descarte foram desconsiderados. O descarte desse material, mesmo quando controlado por políticas públicas, tem sido negligenciado, levando à contaminação desse material, conforme observado pela análise qualitativa da difração de raios X. Esses contaminantes atuam durante o processo de nucleação e crescimento de cristais de gesso, alterando o tamanho e sua forma. Este estudo avalia as propriedades físicas e mecânicas da reciclagem de resíduos de gesso obtidos em recicladores credenciados por órgãos públicos em estado puro e com a inserção de álcool polivinílico e ácido cítrico como retardadores do tempo de preparação comparando os resultados obtidos com o gesso comercial. Os resultados indicam que, nos casos de adição de álcool polivinílico, há ganho nas propriedades mecânicas quando comparado ao produto comercial e melhor trabalhabilidade quando comparado ao gesso reciclado puro, enquanto com a adição de ácido cítrico, essas propriedades são reduzidas nas duas comparações.Palavras-chave: Reciclagem. PVAl. Ácido Cítrico. Gesso. ABSTRACTGypsum is a widely used construction material due to its lightness and low cost, but it becomes an environmental liability as the waste generated in the construction and demolition of buildings is improperly disposed of and can cause great damage to the soil and groundwater. Its recyclability has been extensively studied, but environmental and management factors in the disposal have been disregarded. The disposal of this material, even when controlled by public policies, has been neglected, leading to the contamination of this material, as observed by the X-ray diffraction qualitative analysis. These contaminants act during the process of nucleation and growth of gypsum crystals, altering size and their form. This study evaluates the physical and mechanical properties of the recycling of gypsum waste obtained in recyclers accredited by public agencies in the pure state and with the insertion of polyvinyl alcohol and citric acid as retarders of setting-time comparing the obtained results with commercial gypsum. The results indicate that in the cases of addition of polyvinyl alcohol there is gain in the mechanical properties when compared to the commercial product and better workability when compared to pure recycled gypsum. While with the addition of citric acid these properties are reduced in both comparisons.Keywords: Recycling. PVAl. Citric Acid. Plaster.


2013 ◽  
Vol 421 ◽  
pp. 250-254 ◽  
Author(s):  
Hua Shen ◽  
He Liang ◽  
Wei Dong Yang ◽  
Guang Chun Yao ◽  
Chuan Sheng Wang

The effects of yttrium (Y) on microstructures and mechanical properties of aluminium alloy were investigated in detail by scanning electronic microscope (SEM), energy dispersive spectrum (EDS),X-ray diffraction and tensile test. The results show that the trend of alloys tensile strength and elongation with increasing of the Y content is a broken line. When the Y content is increased up to 0.30%, the tensile strength and elongation are 105MPa and 10.50% respectively, meanwhile, the fractograph exhibited typical ductile dimple fracture pattern. Then the alloy performance is best. The high strength of aluminum alloy is attributed to the size of Al2Y phase. Addition of Y above 0.30% in aluminum alloy may generate more the coarse Al2Y particle. It can induce the decrease in the material performance.


Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  

Abstract USS STRUX is an alloy steel designed for use in the heat treated condition at a minimum tensile strength of 280,000 psi. At this very high strength level the steel has adequate ductility and notch toughness for critical applications. This datasheet provides information on composition and tensile properties. Filing Code: SA-100. Producer or source: United States Steel Corporation.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 647 ◽  
Author(s):  
Bingrong Zhang ◽  
Lingkun Zhang ◽  
Zhiming Wang ◽  
Anjiang Gao

In order to obtain high-strength and high-ductility Al–Si–Cu–Mg alloys, the present research is focused on optimizing the composition of soluble phases, the structure and morphology of insoluble phases, and artificial ageing processes. The results show that the best matches, 0.4 wt% Mg and 1.2 wt% Cu in the Al–9Si alloy, avoided the toxic effect of the blocky Al2Cu on the mechanical properties of the alloy. The addition of 0.6 wt% Zn modified the morphology of eutectic Si from coarse particles to fine fibrous particles and the texture of Fe-rich phases from acicular β-Fe to blocky π-Fe in the Al–9Si–1.2Cu–0.4Mg-based alloy. With the optimization of the heat treatment parameters, the spherical eutectic Si and the fully fused β-Fe dramatically improved the ultimate tensile strength and elongation to fracture. Compared with the Al–9Si–1.2Cu–0.4Mg-based alloy, the 0.6 wt% Zn modified alloy not only increased the ultimate tensile strength and elongation to fracture of peak ageing but also reduced the time of peak ageing. The following improved combination of higher tensile strength and higher elongation was achieved for 0.6 wt% Zn modified alloy by double-stage ageing: 100 °C × 3 h + 180 °C × 7 h, with mechanical properties of ultimate tensile strength (UTS) of ~371 MPa, yield strength (YS) of ~291 MPa, and elongation to fracture (E%) of ~5.6%.


2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Yongfang Qian ◽  
Zhen Zhang ◽  
Laijiu Zheng ◽  
Ruoyuan Song ◽  
Yuping Zhao

Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL) blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θof 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.


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