scholarly journals Evaluation of properties of elastomer seal for fuel systems exposed to effects of rapeseed methyl ester 

2017 ◽  
Vol 63 (No. 3) ◽  
pp. 115-120
Author(s):  
Šleger Vladimír ◽  
Müller Miroslav ◽  
Pexa Martin

Elastomer seals in fuel systems have to evince required mechanical properties also at exposure to fuels. The aim of the research was to determine an influence of various concentrations of rapeseed methyl ester (RME) on a change of mechanical properties of sealing O-rings made from polyacrylate elastomer (an indication ACM). A permanent deformation – compression set (CS), a tensile strength and an elongation after the exposure to the tested environment for the time 20 months were evaluated within the experiment. A fall of the tensile strength, the elongation and the permanent deformation – compression set CS was proved depending on the type of the fuel. The increased negative influence of various concentrations of RME (20% to 100%) on the tested properties of the sealing O-rings compared with the diesel oil complying with the standard EN 590:2004 was not proved. So a significant negative influence of degradation aspects on the tested properties of the O-rings of the ACM type (polyacrylate elastomer) was not proved.

2017 ◽  
Vol 735 ◽  
pp. 153-157
Author(s):  
Wasinee Pinpat ◽  
Wirunya Keawwattana ◽  
Siree Tangbunsuk

Silica has been used as reinforcing filler in natural rubber for a period of time as it results in excellent properties for NR vulcanizes. Rice husk ash (RHA), bagasse ash (BA), and oil palm ash (OPA) obtained from agricultural wastes are mainly composed of silica in the percentage of 80.00%, 57.33%, and 40.20% by weight, respectively. The effect of these fillers on cure characteristics and mechanical properties of natural rubber materials at fixed silica content at 35 parts per hundred of rubber (phr) were investigated. The results indicated that ashes showed greater cure time compared to that of the silica. The incorporation of ashes into natural rubber gradually improved compression set but significantly decreased tensile strength, elongation at break, and resilience. Moreover, young's modulus increased, while hardness showed no significant change with the addition of ashes. Overall results indicated that ashes could be used as cheaper fillers for natural rubber materials where improved mechanical properties were not critical.


2013 ◽  
Vol 59 (No. 4) ◽  
pp. 121-127
Author(s):  
P. Trávníček ◽  
M. Valach ◽  
Z. Hlaváčová ◽  
J. Mareček ◽  
T. Vítěz ◽  
...  

The goal of this study was the determination of basic physical properties such as density, calorific value and rheological properties of liquid biofuels. Biofuels on the base of bioethanol and rapeseed methyl ester were chosen. Following control samples were selected: diesel oil without admixture of methyl esters and commercially available diesel oils with small amount of methyl ester admixture (6.2 and 6.5%). Dynamic viscosities of individual samples were measured in the range from –10°C to 50°C. Then dependence of shear rate on shear stress was measured at temperatures –10, 0, 20 and 40°C. The most of samples showed the Newtonian behaviour. However, samples with high content of methyl esters or pure methyl esters showed thixotropy behaviour at the low temperature.


2012 ◽  
Vol 58 (No. 2) ◽  
pp. 37-45
Author(s):  
M. Pexa ◽  
K. Kubín

This paper describes the effect of a mixture of rapeseed methyl ester and diesel oil on fuel consumption and power parameters of tractor engine. The hydraulic dynamometer was used to load the engine of Zetor Forterra 8641 tractor over rear power take-off. The measured tractor is almost new with less than 100 h worked. The measurements were realized for several ratios of diesel oil and rapeseed methyl ester (from pure diesel to pure rapeseed methyl ester). The engine was loaded by the dynamometer in several working points which were predefined by engine speed and its torque. The fuel consumption was measured by the flow meter in each of these points. The reduction of engine’s power parameters and the increase of specific fuel consumption are expected due to the nature of rapeseed methyl ester such as e.g. lower calorific value.  


2017 ◽  
Vol 17 (2) ◽  
pp. 145-150
Author(s):  
T. Wróbel ◽  
J. Szajnar ◽  
D. Bartocha ◽  
M. Stawarz

AbstractThe paper presents the research results of horizontal continuous casting of ingots of aluminium alloy containing 2% wt. silicon (AlSi2). Together with the casting velocity (velocity of ingot movement) we considered the influence of electromagnetic stirring in the area of the continuous casting mould on refinement of the ingot’s primary structure and their selected mechanical properties, i.e. tensile strength, yield strength, hardness and elongation. The effect of primary structure refinement and mechanical properties obtained by electromagnetic stirring was compared with refinement obtained by using traditional inoculation, which consists in introducing additives, i.e. Ti, B and Sr, to the metal bath. On the basis of the obtained results we confirmed that inoculation done by electromagnetic stirring in the range of the continuous casting mould guarantees improved mechanical properties and also decreases the negative influence of casting velocity, thus increasing the structure of AlSi2 continuous ingots.


2014 ◽  
Vol 60 (No. 1) ◽  
pp. 1-9
Author(s):  
M. Pexa ◽  
K. Kubín

This paper describes the effect of a mixture of rapeseed methyl ester and diesel oil on emission production of tractor engine. The hydraulic dynamometer was used to load the engine of Zetor Forterra 8641 tractor over rear power take-off. The measured tractor is almost new with less than 100 h worked. The measurements were realized for several ratios of diesel oil and rapeseed methyl ester (from pure diesel to pure rapeseed methyl ester). The engine was loaded by the dynamometer in several working points which were predefined by engine speed and its torque. The production of carbon monoxide (CO), carbon dioxide (CO<sub>2</sub>), hydrocarbons (HC), nitrogen oxides (NO<sub>x</sub>) and particulate matter (PM) were measured in each of these points. The comparison of different fuels was performed using the Non-Road Steady Cycle (NRSC) test procedure. Engine maps were also created for each emission component and for all of tested fuels. &nbsp; &nbsp;


2006 ◽  
Vol 79 (4) ◽  
pp. 694-711 ◽  
Author(s):  
M. M. Alvarez Grima ◽  
A. G. Talma ◽  
R. N. Datta ◽  
J. W. M. Noordermeer

Abstract Peroxide cure is an important and widely used cure system for rubber. Several properties obtained via peroxide vulcanization are superior and not achievable with sulfur vulcanization, e.g.: aging resistance, no reversion and low compression set. However, other properties such as tensile strength and dynamic properties, are inferior to those of sulfur vulcanizates. The use of co-agents in peroxide cure leads to a certain extent to improvement in mechanical properties such as tensile strength. Nevertheless the properties are still inferior with respect to mechanical/dynamical properties of sulfur-cured articles. If these properties can be improved, the range of applications of peroxide cure in the rubber industry can be significantly broadened. Scorch is a common problem in peroxide cure, especially for injection molding and extrusion applications. Several additives can help to improve scorch safety, however, they always result in a lower peroxide efficiency, thus inferior vulcanizate properties. In the present study a new concept of co-agents for peroxide vulcanization is introduced. This new concept consists of the use of a combination of a bismaleimide type co-agent, like N,N′-m-phenylenedimaleimide (BMI-MP), and a sulfur containing compound, like dipentamethylenethiuram tetrasulfide (DPTT). This combination provides scorch safety and at the same time improves the mechanical properties of the vulcanizates. Within the bismaleimide type co-agents N,N′-p-phenylenedimaleimide (BMI-PP) provides better mechanical properties than BMI-MP. The concentration of co-agent and sulfur containing compound have a big influence on the scorch time and on the mechanical properties. Optimal properties are reached with 4 phr of co-agent and 0.7 to 0.96 phr of sulfur containing compound.


2020 ◽  
Vol 9 (1) ◽  
pp. 2606-2611

In this present work NBR/PVC conventional composite containing 70phr carbon black (CB) is taken for study. In order to reduce the utilization of CB, new hybrid nanocomposites containing varied content of both CB(40phr -55phr) and graphenenanoplatelets (GNP) (3phr-9phr) were developed by melt-mixing on a two roll mill and their morphology and mechanical properties were tested and compared with conventional composite. FESEM studies evident that the formation of exfoliated structures of GNP and formation of local CB-GNP hybrid filler network which ensures proper and compatible mixing in the composites. It is also found that mechanical properties such as tensile strength, elongation at break, swelling resistance, hardness and compression set increases with increase in GNP content from 3 to 6phr and whereas tensile modulus and tear strength increases with increase in GNP content from 3 to 9phr. Further the developed NBR/PVC hybrid nanocompositescontaining 55phr of CB and 3phr of GNP exhibited an improvement of 6.8%, 27.9% +1 shore A and 4.1% in tensile strength, tensile modulus, hardness, swelling resistance in comparison to the conventional composite containing 70phr CB. The better performance of NBR/PVC hybrid nanocomposites can be mainly attributed to high surface area of functionalized nanographene and its enhanced interactions with the NBR/PVC matrix, enhanced CB-GNP interactions, improved dispersion of graphene in the rubber blend due the presence of COOH group on the surface of graphene layers and formation of more cross-links between rubber and fillers with increase in nanofiller content . These newly developed hybrid nanocomposites can be used in automotive sector especially for oil seal applications where low compression set and high solvent resistance are of prime importance.


2021 ◽  
Vol 39 (4) ◽  
pp. 1142-1149
Author(s):  
A.C. Ezika ◽  
V.U. Okpechi

Effects of chemically treated and carbonized spear grass fibre on the curing and mechanical properties of natural rubber vulcanizates were carried out. Natural rubber (NR) was filled with carbonized (at carbonization temperatures of 400°C, 600°C and 800°C  respectively) and chemically treated (treatment with HCl and NaOH of 5% concentration) spear grass fillers respectively, at a filler loading of 30phr. The rubber compounding was carried out in a bambury mixer. The effect of carbonization temperature and chemical treatment of the filler on the mechanical properties (tensile strength, % elongation, hardness strength, abrasion resistance and compression set) and rheological properties (cure time, scorch time, maximum and minimum torque) were carried out on the  samples. The results of the mechanical properties of carbonized spear grass fibre (C-SGF) filled vulcanizates show that the optimum carbonization temperature for an improved tensile strength, % elongation, hardness, abrasion and compression set was obtained at 400°C. NaOH treated fibre filled vulcanizates showed better mechanical properties; with the highest abrasion resistance of 67.65%, while untreated and acidified fibre filled vulcanizates showed poor mechanical properties. Acidified (HCl) uncarbonized spear grass fibre (U-SGF) filled vulcanizate had the highest compression set of 48% against C-SGF filled vulcanzates and carbon black filled  vulcanizate, with carbon black filled vulcanizate having 47% as its compression set value. This reveals that at a carbonization temperature of 400°C, C-SGF appears to be a potential substitute filler for carbon black (CB). Keywords: Spear Grass Fibre, Natural Rubber, Chemical Treatments, Cure Characteristics, Mechanical Properties, Carbonization


Author(s):  
S. Fujishiro

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.


2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.


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