Search results

1

Thermomechanical and Solid Particle Erosion Behaviour of CaCO₃ and SGF (Short Glass Fibre) Reinforced ABS/PA6 Composites

100%

Şahin A., Yılmaz S., Yılmaz T., Sınmazçelik T.

Acta Physica Polonica A

|

2015

|

vol. 127

|

issue 4

1062-1064

EN

In this study we have investigated thermomechanical and solid particle erosion behaviour of ABS/PA6 composites reinforced with CaCO₃ particles and SGF. ABS/PA6 composites were reinforced with CaCO₃ particles and SGF at different weight ratios (0, 10, 30, 15/15 wt.%). Composite materials were manufactured by twin screw extruder and injection molding machine. Thermomechanical properties were investigated by dynamic mechanical analysis (DMA) method. Moreover erosion wear behaviour was investigated on solid particle erosion test machine. Experimental results show that thermomechanical properties significantly depend on particle types and weight ratios. While storage modulus was found to be maximum for 30 wt.% SGF-reinforced samples, the loss modulus was found to be maximum for 15/15 wt.% hybrid samples. Moreover minimum loss factor values were found for hybrid samples, but glass transition temperature of samples were not effected significantly with CaCO₃ and SGF reinforcement. Erosion behaviour depends on particle impact angle, the type of reinforcing particles and their weight ratios. Maximum erosion rates were found at impingement angle of 30° for 30 wt.% CaCO₃-filled samples. According to experimental results both CaCO₃ and SGF reinforcement have positive influence on thermomechanical properties. However CaCO₃ and SGF reinforcement have reduced the solid particle erosion resistance of ABS/PA6 composites.

2

Effects of Terpolymer Addition on the Thermal and Termomechanical Properties of Poly(Phenylene Sulfide)

100%

Cetin B., Sahin A., Yilmaz T., Sinmazcelik T., Curgul I.

Acta Physica Polonica A

|

2017

|

vol. 131

|

issue 3

598-600

EN

Poly(phenylene sulfide) (PPS) is one of the high-performance engineering polymers and it exhibits superior behavior, such as electrical insulation, dimensional and thermal stability, chemical resistance for various industrial applications. In addition to this, PPS has a high degree of crystallinity and it maintains these properties at high temperatures. These advantageous properties of PPS can be dependent on its chemical structure, composed of phenyl groups linked by a sulfur atom, which gives rigidity to the polymer chains. Owing to these properties, PPS is widely used in electrical and electronic components, automobile industry and mechanical applications. On the other hand, brittleness of PPS restricts its further applications. For this reason, ethylene-acrylic ester-glycidyl methacrylate terpolymer (Lotader®-AX8900) was used to overcome the brittleness of PPS. The effects of terpolymer addition on the thermal and thermomechanical properties of blends were investigated in this study. PPS/Lotader (0, 2, 5, 10 wt.% Lotader®) blends of various compositions were prepared. The blends were prepared by using laboratory scale micro compounder and injection molding machine. Thermomechanical and thermal properties of blends were investigated by means of dynamic mechanic analysis and differential scanning calorimeter test methods. As a result of this study, it was found that increasing loading level of Lotader® significantly decreased the crystallinity and increased glass transition temperature of PPS. On the other hand, Lotader® addition did not affect the melting temperature of PPS considerably. Results of dynamic mechanic analysis test revealed that while damping factor peak and loss modulus values of blends increased with the addition of Lotader®, storage modulus of blends decreased with the increasing loading level of Lotader®. When all test results are considered, it can be concluded that Lotader addition changes the brittle nature of PPS to ductile nature. In addition to this, 2 wt.% Lotader addition to PPS enables the optimum ductility for PPS without deteriorating its other properties.

3

Modeling of the Viscosity Behavior in the Interface Area of Two Miscible Liquids

100%

Szwajczak E., Stragaczyński R., Herba H., Świergiel J., Jadżyn J.

Acta Physica Polonica A

|

2009

|

vol. 115

|

issue 5

905-908

EN

The paper presents the results of the share viscosity (η) investigations performed for binary mixtures composed of the liquids of extremely different viscosities: a high-viscous α-tocopherol acetate (η ≈ 10 Pa s) is mixed with 4-n-propylcyclohexyl-4'-n-pentylphenyl (η ≈ 10 mPa s) and mesitilene (η ≈ 1 mPa s), the two low-viscous solvents composed of the non-polar molecules of an essentially different shape. It was found that the viscosities of the mixtures, disregarding the molecular shape of the non-polar admixture, exhibit a strong nonlinear dependence on tocopherol mole fraction and, at a given temperature, the dependence can be described with an exponential function. For a constant tocopherol concentration in the mixtures, the viscosity temperature dependences are well described with the Vogel-Fulcher-Tammann relation. The results can be considered as a model of the viscosity behavior related to the laminar flow of miscible liquids of a different viscosity being in contact to each other.

4

Molecular Dynamics in Cyclic Olefin Copolymer

88%

Makrocka-Rydzyk M., Orozbaev B., Nowaczyk G., Głowinkowski S., Jurga S.

Acta Physica Polonica A

|

2005

|

vol. 108

|

issue 2

385-393

EN

Nuclear magnetic resonance, broadband dielectric spectroscopy and dynamic-mechanical thermal analysis were employed to study molecular dynamics of ethylene-norbornene copolymer. The analysis of experimental data indicates existence of three motional processes denoted asαβ, andγ in order of decreasing temperature. Theα relaxation is related to the dynamic glass transition, while theβ relaxation, observed only for the untreated sample, is assigned to short range segmental motions involving norbornene units. Theγ relaxation is due to very local motions of ethylene units e.g. trans-gauche isomerization, similar to those responsible forγ relaxation in polyethylene. The rate of motion accountable for γ process, follows the Vogel-Fulcher-Tammann equation, similarly to α transition, indicating cooperative nature of the motion.

5

Analysis of Complex Viscosity in a Group of Patients with Circulation Disorders

88%

Marcinkowska-Gapińska A., Kowal P.

Acta Physica Polonica A

|

2012

|

vol. 121

|

issue 1A

A-54-A-56

EN

Rheology of viscoelastic fluids is a complex phenomenon. Full blood is an example of a body fluid of non-Newtonian character with pronounced viscoelastic properties. Blood flow in the circulatory system depends not only on the physical and physico-chemical properties of blood but also on the structure and properties of the vascular system. Blood viscosity is one of the most important factor determining the blood flow. Its value depends on the shear rate, hematocrit, erythrocyte aggregability and deformability, and on the plasma viscosity and composition. In the course of the investigation we utilized oscillatory methods, called also dynamic mechanical analysis. The technique principle is based on the measurement of the amplitude and phase of oscillations of the sample subject to a harmonic force with certain amplitude and frequency. The results of dynamic mechanical analysis were used to determine the viscoelastic properties of blood samples. We performed also the standard flow curve measurements of the blood plasma samples, that is shear stress as a function of shear rate in the rotary mode. All measurements were performed by means of a Contraves LS-40 rheometer on blood samples taken from two groups of patients. One group contained patients after heart attack, while the second one - after cerebral infarction. In none of the groups the patients were in an acute state. Information obtained from oscillatory measurements indicate increased erythrocyte aggregability in both groups of patients.

6

Analysis of the Effect of Magnetostimulation on Viscoelastic Properties of Blood in Patients with Lasting Pain

75%

Marcinkowska-Gapińska A., Kowal P.

|

vol. 125

|

issue 4A

A-24-A-26

EN

The aim of the current work was to analyze the influence of alternating magnetic field on the viscoelastic properties of blood in vivo in patients with lasting pain problems. Oscillatory techniques, also called the dynamic mechanical analysis, have been used in the current work to study the viscoelastic properties of blood. The blood samples were collected from patients of a neurological ward complaining about spinal cord and lower limbs pain. Altogether 25 patients took part in the study. A blood sample was collected from each patient twice: before the magnetostimulation and after five treatments. For each blood sample, the hematocrit value was measured using the standard method. Plasma viscosity and the complex whole blood viscosity were measured by means of a rotary-oscillating rheometer Contraves LS40. Magnetic field was generated by the instrument Viofor JPS and the magnetostimulation treatments were performed using different programs. The analysis of the results included estimation of the hematocrit value, plasma viscosity, complex whole blood viscosity and its components: viscous and elastic viscosity at four chosen amplitudes of the shear rate as a function of the applied treatment program. The results obtained in the study suggest that rheological properties of blood change depending on the applied magnetostimulation program.

7

Polymer - Bonded Magnetic Materials with Various Nd-Fe-B Filler Content

75%

Grujić A., Lazić N., Talijan N., Spasojević V., Stajić-Trošić J., Ćosović V., Aleksić R.

|

issue 5

859-863

EN

One of the more important developments in magnetic materials, polymer bonded magnets, have opened a new world of application opportunities. The Nd-Fe-B/polymer composite materials offer an excellent combination of strong magnetic and dynamical-mechanical properties. However, the transition temperatures of filler and matrix should be selected carefully considering the future application. Uniform particle distribution and good adhesion between Nd-Fe-B powder particles and polymer are essential for the quality of the composite, while stiffness of polymer matrix is one of the influencing factors as well. The damping properties of Nd-Fe-B/polymer composites with 15 wt.%, 50 wt.% and 75 wt.% of Nd-Fe-B powder were studied by dynamic mechanical analysis and compared with a pure polymer sample. Thermal stability was analyzed using a simultaneous differential scanning calorimetric and thermogravimetric analysis technique.

Refine search results

Thermomechanical and Solid Particle Erosion Behaviour of CaCO₃ and SGF (Short Glass Fibre) Reinforced ABS/PA6 Composites

Effects of Terpolymer Addition on the Thermal and Termomechanical Properties of Poly(Phenylene Sulfide)

Modeling of the Viscosity Behavior in the Interface Area of Two Miscible Liquids

Molecular Dynamics in Cyclic Olefin Copolymer

Analysis of Complex Viscosity in a Group of Patients with Circulation Disorders

Analysis of the Effect of Magnetostimulation on Viscoelastic Properties of Blood in Patients with Lasting Pain

Polymer - Bonded Magnetic Materials with Various Nd-Fe-B Filler Content