scholarly journals Evaluation of Tribological Properties of Polymer Materials Used for Sliding Bearings in Agricultural Machinery

2017 ◽  
Vol 21 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Mariusz Walczak ◽  
Jacek Caban ◽  
Andrzej Marczuk

Abstract The continuous technological development requires the use of modern materials also in agricultural engineering. Knowledge of the characteristics of tribological materials pairs cooperating with each other is useful for developing sliding nodes of agricultural machinery. Tribological properties of materials should be assessed for selection of technological materials beyond the economic criterion. The article presents analysis of the characteristics of tribological ball-on-disc wear of polymeric materials used as sliding elements for farm machines. Tribological tests were carried out under dry friction for a polymer-metal pair, and a wear rate and friction coefficient of the sample; the signs of wear were submitted to SEM observations.

2021 ◽  
Vol 11 (1) ◽  
pp. 624-629
Author(s):  
Mariusz Walczak ◽  
Jacek Caban

Abstract The automotive industry uses a variety of technologies and construction materials in production process. Knowledge of the characteristics of tribological material pairs cooperating with each other is useful for their selection from the safety point of view sliding pairs, in means of transport, and other machines. The aim of the contribution is the analysis of the characteristics of tribological ball-on-disc wear of polymeric materials used as sliding bearings. Tribological tests were carried out under dry friction for a polymer–metal pair of three types of materials. Among all three groups of the tested materials statistically significant differences (p < 0.05 in Student’s t-test) in wear were observed. The wear rate and friction coefficient of the sample were tested, and the signs of wear were submitted to SEM observations.


2020 ◽  
Vol 128 ◽  
pp. 81-88 ◽  
Author(s):  
Paweł Kowalik ◽  
Mariusz Fabijański

The purpose of this study is to present the requirements, methodology, and results of research on the impact of biodegradable oil on plastic components used in the construction of a railway turnout. Briefly discussed are what railroad turnouts are, how they work, and what problems occur with substances used for their lubrication. They have an impact on the mechanical properties and durability of products made of polymeric materials. These types of materials absorb various kinds of chemicals, to a greater or lesser degree, and this affects their properties. For the tests, we used a universal lubrication oil with biodegradable properties, which is its most significant advantage. However, it may not cause deterioration of the turnout operation and change the properties of materials used for its construction. These types of oils require more frequent applications on cooperating components. We used the two most popular polymer materials. The first is high-density polyethylene (HDPE), used to make all kinds of rail spacers, dowels for fixing rails, sleeves, etc. The second, polyurethane (PUR) is most commonly used for rail pads of various shapes. The methodology and results of testing the impact of a lubricant (biodegradable oil) on the change of mechanical properties such as strength and hardness are presented. The tests were carried out at various temperatures; the time of exposure to oil was seven days; the results were referred to samples conditioned under standard conditions. The tests carried out on the impact of the biodegradable lubricant on polymeric materials (HDPE and PUR) showed little effect on the change of strength parameters of these materials. Celem niniejszego opracowania jest przedstawienie wymagań, metodyki oraz wyników badań oddziałania biodegradowalnego oleju na elementy z tworzyw sztucznych stosownych w budo-wie rozjazdu kolejowego. Krótko omówiono czym są rozjazdy kolejowe i jak działają oraz jakie występują problemy z substancjami używanymi do ich smarowania, które nie pozostają bez wpływu na właściwości mechaniczne i trwałość wyrobów z materiałów polimerowych. Materiały tego typu wchłaniają różnego rodzaju substancje chemiczne w większym lub mniejszym stopniu, a to ma wpływ na ich właściwości. Do badań został wykorzystany uniwersalny olej do smarowania o biodegradowalnych właściwościach, co jest jego największą zaletą. Jednak nie może on powodować pogorszenia pracy rozjazdu oraz zmieniać właściwości materiałów użytych do jego budowy. Tego typu oleje wymagają częstszego aplikowania na elementy współpracujące ze sobą. W pracy wykorzystano dwa najbardziej popularne materiały polimerowe. Pierw-szy to polietylen o dużej gęstości (HDPE), z którego wykonuje się wszelkiego rodzaju przekładki podszynowe, dyble do mocowania szyn, tuleje, itp. Drugi to poliuretan (PUR) stosowany najczęściej na przekładki podszynowe o różnym kształcie. Zaprezentowano metodykę i wyniki ba-dań oddziaływania środka smarnego (biodegradowalnego oleju) na zmianę właściwości mechanicznych takich jak wytrzymałość oraz twardość. Badania zostały przeprowadzone w różnych temperaturach, a czas ekspozycji na olej wynosił 7 dób, wyniki odniesiono do próbek klimatyzowanych w standardowych warunkach. Przeprowadzone badania oddziaływania biodegradowalnego środka smarnego na tworzywa polimerowe (HDPE i PUR), wykazały niewielki wpływ na zmianę parametrów wytrzymałościowych tych materiałów.


Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5579
Author(s):  
Ivo Domagała ◽  
Krzysztof Przystupa ◽  
Marcel Firlej ◽  
Daniel Pieniak ◽  
Agata Niewczas ◽  
...  

This paper discusses the issues of strength and creep of polymeric materials used in orthodontic appliances. Orthodontic biomechanics is focused on the movement of individual teeth or dental groups as a result of the force applied by orthodontic appliances. Stresses in the construction of functional and biomechanical appliances is generated when using the apparatus in the oral cavity. The orthodontic appliance must maintain its shape and not be damaged during treatment so strength and creep resistance are fundamental properties. It was assumed that the clinical success of orthodontic appliances can be determined by these performance properties. The aim of the work was the experimental assessment of comparative bending strength and creep resistance of selected popular polymer materials used in the production of biomechanical orthodontic appliances. Four commercial materials manufactured by the world class producers were tested: NextDent Ortho Rigid (Vertex-Dental B.V., Soesterberg, The Netherlands) marked as “1A”; Erkocryl (ERKODENT Erich Kopp GmbH, Pfalzgrafenweiler, Germany)-“2A”; Vertex Orthoplast (Vertex Dental B.V.), blue, marked as “3A” and material with the same name as “3A” but orange, marked in the article as “4A”. All the tests were carried out after aging in artificial saliva for 48 h at a temperature of 37 °C. Flexular strength and flexular modulus were made using the three point bending method according to the ISO 178 technical standard. Creep tests were carried out according to the method contained in ISO 899-2. The creep test was carried out in an artificial saliva bath at 37 °C. The creep tests showed significant differences in the strength, modulus and deformability of the tested materials. The strength reliability of the tested materials also varied. The research shows that the 2A material can be used for orthodontic applications in which long-term stresses should be lower than 20 MPa.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2925
Author(s):  
Ivo Domagała ◽  
Krzysztof Przystupa ◽  
Marcel Firlej ◽  
Daniel Pieniak ◽  
Leszek Gil ◽  
...  

Background: Clinical success depends on the contact strength and wear resistance of medical devices made of polymer materials. The scientific goal resulted from the problem of using different methods of surface evaluation of materials used in the production of orthodontic appliances. The purpose of the work was an experimental comparative assessment of indentation hardness and scratch hardness and the sliding wear of four selected polymeric materials used in the manufacture of orthodontic appliances. Methods: Four commercial materials were compared. Shore hardness tests and a scratch test with a Rockwell indenter were performed. A sliding wear test was performed using the ball-on-disc method. Statistical PCA and correlation analyses were performed. Results: The results of scratch hardness measurements using a contact profilometer correlated with the Shore hardness to a greater extent than measurements made using an optical microscope. PCA showed that Shore hardness explains 45% of the total variance in all the results across the materials. Conclusions: The scratch hardness method allows for a more explicit ranking of orthodontic polymeric materials when measurements are made with a profilometer. The ranking of sliding wear resistance should be made separately.


2021 ◽  
Vol 30 (1/2) ◽  
pp. 12-19
Author(s):  
Woongbi CHO ◽  
Jeong Jae WIE

Triboelectric nanogenerators (TENGs) are eco-friendly energy-harvesting systems that produce electrical energy from disordered mechanical energy. To enhance the triboelectric performances of TENGs, many researchers have conducted in-depth studies of the polymer materials utilized in TENGs, so numerous studies have been reported on the relationship between their material properties and their energy-harvesting capabilities. Triboelectric performance depends on the electrical properties of the materials used, such as their electron affinities and dielectric constants. Representative examples of positive and negative tribomaterials include PA6, PEO, PVDF, and fluorinated sulfur copolymers, respectively. This article introduces the relationship among the compositions, structures, triboelectric performances of the polymer materials, and composites used in TENGs and summarizes the representative polymer materials applied in the latest TENGs.


Tribologia ◽  
2020 ◽  
Vol 292 (4) ◽  
pp. 17-26
Author(s):  
Mariusz Opałka ◽  
Piotr Kowalewski ◽  
Anita Ptak

The paper presents numerical calculations of polymer sliding bearings during their operation at low temperatures. Calculations of the frictional moment and the contact area were performed for bearing pans made of PA and PEEK. In the numerical model, the influence of temperature on the mechanical properties (modulus of longitudinal elasticity) and tribological properties (coefficient of friction) were taken into account. The diversified influence of the temperature and thickness of the polymer bearing pans was demonstrated with regards to elements made of different polymer materials. At low temperatures (up to T = -50°C), a different (depending on the used polymer) influence of mechanical and tribological properties on the resistance to motion was found. The ABAQUS calculation package and the finite element method (FEM) were used in the calculations.


2019 ◽  
Vol 5 (11) ◽  
pp. 242-248 ◽  
Author(s):  
T. Almataev ◽  
N. Almataev ◽  
D. Moidinov

Results of research and development of composite polymer materials are presented. The aim of this work was the study and development of new composite polymer materials with optimal performance properties for the working bodies of machines and mechanisms. The surface grinding of the samples was carried out using an eccentric rotary brush according to the procedure previously presented by the authors. Tribological properties of polymeric materials and coatings were determined on a tribometer. The results of the study showed that the degree of influence of fillers on the strength and antifriction properties of composite polymer materials depends on the type and nature of the filler and binder.


Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.


2020 ◽  
Vol 67 (2) ◽  
pp. 115-120
Author(s):  
Raisa A. Alekhina ◽  
Victoriya E. Slavkina ◽  
Yuliya A. Lopatina

The article presents options for recycling polymers. The use of biodegradable materials is promising. This is a special class of polymers that can decompose under aerobic or anaerobic conditions under the action of microorganisms or enzymes forming natural products such as carbon dioxide, nitrogen, water, biomass, and inorganic salts. (Research purpose) The research purpose is in reviewing biodegradable materials that can be used for the manufacture of products used in agriculture. (Materials and methods) The study are based on open information sources containing information about biodegradable materials. Research methods are collecting, studying and comparative analysis of information. (Results and discussion) The article presents the advantages and disadvantages of biodegradable materials, mechanical properties of the main groups of biodegradable polymers. The article provides a summary list of agricultural products that can be made from biodegradable polymer materials. It was found that products from the general group are widely used in agriculture. Authors have found that products from a special group can only be made from biodegradable polymers with a controlled decomposition period in the soil, their use contributes to increasing the productivity of crops. (Conclusions) It was found that biodegradable polymer materials, along with environmental safety, have mechanical properties that allow them producing products that do not carry significant loads during operation. We have shown that the creation of responsible products (machine parts) from biodegradable polymers requires an increase in their strength properties, which is achievable by creating composites based on them. It was found that the technological complexity of their manufacture and high cost are the limiting factors for the widespread use of biodegradable polymers at this stage.


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