scholarly journals The effect of rubber on the mechanical properties of epoxy and carbon fiber (Review)

Author(s):  
M. N. Meiirbekov ◽  
◽  
M. B. Ismailov ◽  

The paper presents published data on the effect of rubber elastomers on the strength properties of epoxy resin (ES) and carbon fiber. The introduction of 10% rubbers into ES ED-20 leads to an increase in compressive strength by 50%, tensile strength by 51%, impact strength by 133% and elongation by 128%. The optimal content of rubber with carboxyl groups for the OLDEN mixture was 10-12.5%, while the increase in compressive strength was 48%, impact strength - 73% and elongation - 187%. For DER 331 resin, the study was conducted with two hardeners Piperidine and DETA. The best results for Piperidine hardener were obtained on rubber with hydroxyl groups, with its optimal content of 2.5%, impact strength increased by 170%. For the hardener DETA, the best results were obtained on rubber with carboxyl groups at its optimal content of 10%, the increase in impact strength was 66%. When modifying carbon fiber with rubbers, it leads to a significant increase in the yield strength in tension by 42%, the modulus of elasticity in bending by 63%, and with a slight loss of impact strength.

2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.


2012 ◽  
Vol 174-177 ◽  
pp. 1459-1462
Author(s):  
Gui Qiu Huang ◽  
Zhen Huang ◽  
Jing Jiang ◽  
Xue Yuan Deng

This paper focuses on the mechanical properties of carbon fiber cloth reinforced bamboos. Using the carbon fiber cloth to reinforce circularly the bamboo can protect dry bursting of the bamboos and improve its mechanical performances. A series of experiments were carried out to investigate the compressive strength, tensile strength and bending strength of bamboo reinforced with carbon fiber cloth. The mechanical performances of bamboos with and without reinforcing were compared and the efficient reinforcing method was suggested, with such method the compressive strength and bending strength of carbon fiber reinforced bamboos could be increased obviously compared with that of bamboos without reinforcing.


2021 ◽  
Vol 8 ◽  
Author(s):  
Shi Wang ◽  
Xuepeng Song ◽  
Meiliang Wei ◽  
Wu Liu ◽  
Xiaojun Wang ◽  
...  

The tailings and rice straw are waste by-products, and the storage of tailings on the ground and the burning of rice straws will seriously damage the ecological environment. In this study, the effect of different contents of alkalized rice straw (ARS; rice straw was alkalized with 4% NaOH solution) on the mechanical properties and microstructure of cemented tailings backfill (CTB; ARSCTB) was studied through uniaxial compressive strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests. The results indicated that 1) the UCS of ARSCTB could be improved by ARS. However, with the increase in the ARS content from 0.1 to 0.4 wt%, the UCS showed a monotonous decreasing trend. The UCS improvement effect was best when the ARS content was 0.1 wt%, and at 7, 14, and 28 days curing ages, the UCS increased rate was 6.0, 8.3, 14.7% respectively. 2) The tensile strength of ARSCTB was generally higher than that of CTB and positively correlated with the ARS content. The tensile strength increase rate was 24.1–34.2% at 28 days curing age. 3) The SEM test indicated that the ARS was wrapped by cement hydration products, which improves its connection with the ARSCTB matrix. ARS performed a bridging role, inhibited cracks propagation, and provided drag or pulling force for the block that is about to fall off. Therefore, the mechanical properties of ARSCTB were enhanced. However, under high ARS content, the inhibition of ARS on hydration reaction and the overlap between ARS were not conducive to the improvement of the UCS of ARSCTB. 4) The post-peak residual strength and integrity effect of ARSCTB were greater. It is recommended to add 0.1–0.2 wt% ARS to the backfill with high compressive strength requirements such as the empty field subsequent filling mining method and the artificial pillar. 0.3–0.4 wt% ARS is incorporated into backfill with high tensile strength requirements such as high-stage filling with lateral exposure and artificial roof. This study further makes up for the blank of the application of plant fiber in the field of mine filling and helps to improve the mechanical properties of backfill through low-cost materials.


Author(s):  
Mostafa Hassani Niaki ◽  
Morteza Ghorbanzadeh Ahangari ◽  
Abdolhossein Fereidoon

This paper studies the mechanical properties of polymer concrete (PC) with three types of resin systems. First, the effect of 0.5 wt% up to 3 wt% basalt fiber on the mechanical properties of a quaternary epoxy-based PC is investigated experimentally, and the best weight percentage of basalt fiber is obtained. The results show that adding basalt fiber to PC caused the greatest enhancement within 10% in compressive strength, 10% in flexural strength, 35% in the splitting tensile strength, and 315% in impact strength. In the next step, the effect of nanoclay particles on the mechanical properties of basalt fiber-reinforced PC (BFRPC) is analyzed experimentally. Nanoclays increase the compressive strength up to 7%, flexural strength up to 27%, and impact strength up to 260% but decrease the tensile strength of the PC. Field-emission scanning electron microscopy (FESEM) analysis is performed to study the fracture surface and morphology of various concrete specimens. In the last step, we consider the effect of two other different resin systems, rigid polyurethane and rigid polyurethane foam on the mechanical properties of reinforced polymer concrete. A comparison study presents that the epoxy PC has a higher specific strength than the polyurethane and ultra-lightweight polyurethane foam PC.


2010 ◽  
Vol 457 ◽  
pp. 132-136
Author(s):  
Dmytry S. Kozak

This work studies the formation of cast structures in hypereutectoid steel modified by alloying modifiers (Fe30Si55Mg7Ca2REM4, Fe34Si55Mg9Ca2 and Fe63Ni30Mg7) together with inoculants Fe20Si60Ba20. It is found that at spheroidizing by 0.7 % Fe63Ni30Mg7 and inoculation by 1.5 % Fe20Si60Ba20 causes the formation of inclusions of nodular graphite with nodularity exceeding 90 % and a structurally-free cementite structure is obtained. The mechanical properties of the steel with nodular graphite modified by Fe63Ni30Mg7 and Fe20Si60Ba20 are as follows: tensile strength (σb) 660-680 МPа, yield strength (σ0.2) 520-540 МPа, percent elongation (δ) 5-8 %, impact strength (КС) 15-35 J/cm2, Brinell hardness (НВ) 241-255. After ferritic annealing these parameters were found to be σb =530-560 МPа, σ0.2=400-430 МPа, δ =20-24 %, КС=160- 180 J/cm2, 150-162 НВ.


2014 ◽  
Vol 7 (1) ◽  
pp. 94-108
Author(s):  
Amer Hameed Majeed ◽  
Mohammed S. Hamza ◽  
Hayder Raheem Kareem

The study covers the effect of nanocarbon black particles (N220) on some important mechanical properties of epoxy reinforced with it [carbon black nanoparticles]. The nanocomposites were prepared with (1 to 10 wt. %) of carbon black nanoparticles using ultrasonic wave bath machine dispersion method. The results had shown that the tensile strength , tensile modulus of elasticity, flexural strength and impact strength are improved by (24.02%,7.93%,17.3% and 6% ) respectively at 2wt % .The compressive strength and hardness are improved by (44.4%, 12%) at 4wt%.


Author(s):  
Sergey Savotchenko ◽  
Ekaterina Kovaleva

We study experimentally the influence of mass fraction of L-20 hardener cold cure on mechanical properties of epoxy diane resin ED-20. We measure the hardness, tensile strength, bending strength and impact strength of resin at different values of the hardener mass fraction. It is found that the ratio hardener mass fraction of 1:0.9 leads to the highest values of the hardness, tensile strength, compressive strength and bending strength. The impact viscosity is maximum at the ratio hardener mass fraction of 1:0.8. The optimal ratio of a non-toxic safe hardener to the resin is derived based on obtained mechanical characteristics.


2014 ◽  
Vol 59 (4) ◽  
pp. 1713-1716 ◽  
Author(s):  
R. Dąbrowski

Abstract Mechanical properties of the two-phase titanium alloy Ti6Al7Nb, after the heat treatment based on soaking this alloy in the α + β range, cooling in water or oil and ageing at two selected temperatures, were determined in the hereby paper. The alloy mechanical properties were determined in tensile and impact tests, supported by the fractographic analysis of fractures. In addition, its hardness was measured and the analysis of changes occurring in the microstructure was performed for all variants of the alloy heat treatment. Regardless of the applied cooling rate of the alloy, from a temperature of 970°C followed by ageing at 450 and 650°C, none essential changes were noticed in its microstructure. It was shown that applying less intensive cooling medium (oil) instead of water (before tempering) decreases strength properties indicators, i.e. tensile strength and yield strength as well as hardness (only slightly). The decrease of the above mentioned indicators is accompanied by an increase of an elongation and impacts strength. Fractures of tensile and impact tests are of a ductile character regardless of the applied heat treatment.


2015 ◽  
Vol 815 ◽  
pp. 523-528 ◽  
Author(s):  
Rui Hong ◽  
Kun Zhang ◽  
Bao Ying Liu ◽  
Gang Zhang ◽  
Xiao Jun Wang ◽  
...  

The carbon fiber (CF) reinforced polyphenylene sulfide (PPS) composite was modified by aminated polyphenylene sulfide (PPS-NH2) with different mass fractions. The quantified influence of aminated PPS on PPS/CF composites was investigated. The PPS/CF composite with 7wt% PPS-NH2 showed the best mechanical properties. The tensile strength, flexural strength, flexural modulus and impact strength of the composites increased by 12.5%, 13.0%, 38.5% and 31.5%, respectively. PPS-NH2 hardly influenced the melting process of PPS/CF composite. But the crystallization temperature (Tc) of PPS were obviously increased with the present of aminated PPS.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianglin Zhu ◽  
Jiangxiong Wei ◽  
Qijun Yu ◽  
Mingbiao Xu ◽  
Yuwei Luo

Oil well cement is a type of natural brittle material that cannot be used directly in cementing operations. Fiber is a type of material that can effectively improve the strength and toughness of cement stone, and hybrid fiber materials can more effectively improve the performance of a cement sample. To overcome the natural defects of oil well cement, the new mineral fiber, i.e., wollastonite fiber, and common carbon fiber were used in oil well cement, and the micromorphology, mechanical properties, and stress-strain behavior of the cement were evaluated. The experimental results show that carbon fiber and wollastonite fiber are randomly distributed in the cement paste. The mechanical properties of the cement paste are improved by bridging and pulling out. The compressive strength, flexural strength, and impact strength of cement stone containing only carbon fiber or wollastonite fiber are higher than those of the pure cement, but too many fibers are not conducive to the development of mechanical properties. A mixture of 0.3% carbon fiber with 6% wollastonite fiber in oil well cement slurry results in a greater increase in compressive strength, flexural strength, and impact strength. In addition, compared with blank cement stone, the strain of the mixed cement stone increases substantially, and the elastic modulus decreases by 37.8%. The experimental results supply technical support for the design of a high-performance cement slurry system.


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