Micro-Indentation Test and Morphology of Electron Beam Irradiated HDPE

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behaviour. The aim of the experiments was to study the influence of different doses of Beta radiation to the structure and micro-mechanical properties of polypropylene filled by 30% glass fiber (PP+GF). Hard surface layers of PP+GF can be formed by radiation cross-linking by β – radiation with doses of 33, 66 and 99 kGy. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the PP+GF tested. Micro-mechanical properties increased with increasing value of the dose of irradiation material (increase about 49%). The changes were examined and confirmed by X-ray diffraction.

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Surface Properties of Crosslinking Polyamide Measured by Micro-Indentation Test

Materials Science Forum ◽

10.4028/www.scientific.net/msf.919.111 ◽

2018 ◽

Vol 919 ◽

pp. 111-119

Author(s):

Martin Ovsik ◽

Michal Stanek ◽

Vojtech Senkerik

Keyword(s):

Mechanical Properties ◽

Surface Layer ◽

Surface Properties ◽

Electron Beam Irradiation ◽

Indentation Test ◽

Polymer Chains ◽

Beta Radiation ◽

Cross Linking ◽

Micro Indentation ◽

Different Doses

Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), first in the surface layer and then in the total volume, which resulted in considerable changes in specimen behavior. This paper studies the effect of different doses of ionizing beta radiation on the micro-mechanical properties of commercially available polyamide. The measured results indicate, that electron beam irradiation is very effective tool for improvement of surface properties of PA6. In terms of micro-mechanical properties, the values of micro-hardness of surface layer increased by 24% at radiation dose of 132 kGy, stiffness of surface micro layer by 26% (132 kGy) as a result of different loads (0.5N and 2N). Improvement of micro-mechanical properties of radiated polyamide has a great significance also for industry. The modified polyamide shifts to the group of materials that have considerably better properties. Its micro-mechanical properties make polyamide ideal for a wide application in areas where higher resistance to wear, creep are required. Commonly manufactured PA6 can hardly fulfil these criteria.

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Irradiation of Polyamide Measured by Micro-Indentation Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1120-1121.1179 ◽

2015 ◽

Vol 1120-1121 ◽

pp. 1179-1182

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Adam Skrobak ◽

...

Keyword(s):

Mechanical Properties ◽

Surface Layer ◽

Material Properties ◽

Indentation Test ◽

Polymer Chains ◽

Cross Linking ◽

Indentation Hardness ◽

Chemical Bonds ◽

Depth Sensing ◽

Micro Indentation

Cross-linking is a process in which polymer chains are associated through chemical bonds. This research paper deals with the possible utilization of irradiated polyamide. Influence of the intensity of irradiation on micro-indentation hardness was investigated. Material properties created by β – radiation are measured by micro-indentation test using the DSI method (Depth Sensing Indentation). Hardness increased with increasing dose of irradiation at everything samples; however results of micro-indentation test shows increasing in micro-mechanical properties of surface layer. The highest values of micro-mechanical properties were reached radiation dose of 99 kGy, when the micro-mechanical values increased by about 18%.

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Effect of Beta Low Irradiation Doses on the Filled PA66 Measured by Micro-Indentation Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.415 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 415-418

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Martin Reznicek ◽

...

Keyword(s):

Mechanical Properties ◽

Glass Fibers ◽

Indentation Test ◽

Radiation Doses ◽

Micro Hardness ◽

Polyamide 66 ◽

Depth Sensing ◽

Micro Indentation ◽

Hardness Values ◽

Different Doses

The presented article deals with the research of micro-mechanical properties in the surface layer of modified Polyamide 66 filled by 30% of glass fibers. These micro-mechanical properties were measured by the Depth Sensing Indentation - DSI method on samples which were non-irradiated and irradiated by different doses of the β - radiation. Radiation doses used were 0, 15, 30 and 45 kGy for filled Polyamide 66 with the 6% cross-linking agent (triallyl isocyanurate). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the polyamide 66 tested. The highest values of micro-mechanical properties were reached at radiation dose of 30 kGy, when the micro-hardness values increased by about 64%. The aim of the article is to find out the influence of the radiation on the micro-hardness of the modified glass fiber-filled Polyamide 66 (PA66).

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Micro-Indentation Test of Cross-Linking Polyethylene

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1120-1121.1175 ◽

2015 ◽

Vol 1120-1121 ◽

pp. 1175-1178

Author(s):

Martin Ovsik ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

Martin Reznicek

Keyword(s):

Mechanical Properties ◽

Mechanical Behavior ◽

Indentation Test ◽

Basic Material ◽

Cross Linking ◽

Indentation Hardness ◽

Indentation Modulus ◽

Linear Polyethylene ◽

Radiation Crosslinking ◽

Micro Indentation

Radiation crosslinking of linear polyethylene (LLDPE) is a well-recognized modification of improving basic material characteristics. This research paper deals with the utilization of electron beam irradiated LLDPE on the micro-indentation test. The effect of the irradiation on mechanical behavior of the tested polyethylene was investigated. The results indicate that the mechanical behavior, highly depends on the intensity of irradiation. Toughness and hardness grew with increasing dose of the irradiation LLDPE. Indentation modulus increased from 0.25 to 0.28 GPa and indentation hardness increased from 21.89 to 26.25 MPa. These results indicate advantage crosslinking of the improved mechanical properties.

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LOCAL NANO-MECHANICAL PROPERTIES OF CROSS-LINKED POLYBUTYLENE

Acta Polytechnica CTU Proceedings ◽

10.14311/app.2020.27.0112 ◽

2020 ◽

Vol 27 ◽

pp. 112-115

Author(s):

Martin Ovsík ◽

Michal Staněk ◽

Adam Dočkal ◽

Petr Fluxa

Keyword(s):

Mechanical Properties ◽

High Performance ◽

Polymer Chains ◽

Cross Linking ◽

Indentation Hardness ◽

Indentation Modulus ◽

Depth Sensing ◽

Polybutylene Terephthalate ◽

3D Network ◽

Irradiation Dosage

Cross-linking is a process in which polymer chains are associated through chemical bonds. The cross-linking level can be adjusted by the irradiation dosage and often by means of a cross-linking booster. The polymer additional cross-linking influences the surface nano and micro layers in the way comparable to metals during the thermal and chemical-thermal treatments. Polybutylene terephthalate (PBT) can be found in a group of structural polymers, which are often used in industry, especially in automotive. Applying the technology of electron radiation induces a creation of 3D network structure, which improves the local mechanical properties. These were later measured by a depth sensing indentation (DSI) test. This state of the art method is based on immediate detection of indentation depth in relation to applied force. The creation of 3D network caused an increase in nano-mechanical properties values, such as indentation hardness and indentation modulus, in comparison to the virgin material. The indentation hardness rose by 80%, while the indentation modulus elevated by 62%. The selected structural materials, e.g. PBT, were modified by the electron irradiation in a positive way and as such could be moved to a group of high performance materials.

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Micro-Hardness and Morphology of LDPE Influenced by Beta Radiation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.606.253 ◽

2014 ◽

Vol 606 ◽

pp. 253-256 ◽

Cited By ~ 5

Author(s):

Martin Ovsik ◽

Petr Kratky ◽

David Manas ◽

Miroslav Manas ◽

Michal Stanek ◽

...

Keyword(s):

Mechanical Properties ◽

Hardness Test ◽

Polymer Materials ◽

Beta Radiation ◽

Micro Hardness ◽

X Ray Diffraction ◽

Depth Sensing ◽

Surface Layers ◽

Hardness Values ◽

Different Doses

This article deals with the influence of different doses of Beta radiation to the structure and mico-mechanical properties of Low-density polyethylene (LDPE). Hard surface layers of polymer materials, especially LDPE, can be formed by radiation cross-linking by β radiation with doses of 33, 66 and 99 kGy. Material properties created by β radiation are measured by micro-hardness test using the DSI method (Depth Sensing Indentation). Individual radiation doses caused structural and micro-mechanical changes which have a significant effect on the final properties of the LDPE tested. The highest values of micro-mechanical properties were reached at radiation dose of 66 and 99 kGy, when the micro-hardness values increased by about 21%. The changes were examined and confirmed by X-ray diffraction.

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The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽

10.3390/ma14102623 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2623

Author(s):

Monika Wójcik-Bania ◽

Jakub Matusik

Keyword(s):

Total Pore Volume ◽

Cross Linking ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

The Cross ◽

Chain Lengths ◽

First Time ◽

Substituent Influence ◽

Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

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Copper Containing Glass-Based Bone Adhesives for Orthopaedic Applications: Glass Characterization and Advanced Mechanical Evaluation

10.1101/2020.11.19.390138 ◽

2020 ◽

Author(s):

Sahar. Mokhtari ◽

Anthony.W. Wren

Keyword(s):

Mechanical Properties ◽

Photoelectron Spectroscopy ◽

Structural Changes ◽

Viscoelastic Behavior ◽

Polymer Chains ◽

Nano Particles ◽

X Ray Diffraction ◽

X Ray ◽

Compression Data

AbstractThis study addresses issues with currently used bone adhesives, by producing novel glass based skeletal adhesives through modification of the base glass composition to include copper (Cu) and by characterizing each glass with respect to structural changes. Bioactive glasses have found applications in fields such as orthopedics and dentistry, where they have been utilized for the restoration of bone and teeth. The present work outlines the formation of flexible organic-inorganic polyacrylic acid (PAA) – glass hybrids, commercial forms are known as glass ionomer cements (GICs). Initial stages of this research will involve characterization of the Cu-glasses, significant to evaluate the properties of the resulting adhesives. Scanning electron microscopy (SEM) of annealed Cu glasses indicates the presence of partial crystallization in the glass. The structural analysis of the glass using Raman suggests the formation of CuO nanocrystals on the surface. X-ray diffraction (XRD) pattern and X-ray photoelectron spectroscopy (XPS) further confirmed the formation of crystalline CuO phases on the surface of the annealed Cu-glass. The setting reaction was studied using Fourier transform infrared spectroscopy (ATR-FTIR). The mechanical properties of the Cu containing adhesives exhibited gel viscoelastic behavior and enhanced mechanical properties when compared to the control composition. Compression data indicated the Cu glass adhesives were efficient at energy dissipation due to the reversible interactions between CuO nano particles and PAA polymer chains.

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Printable Alginate Hydrogels with Embedded Network of Halloysite Nanotubes: Effect of Polymer Cross-Linking on Rheological Properties and Microstructure

Polymers ◽

10.3390/polym13234130 ◽

2021 ◽

Vol 13 (23) ◽

pp. 4130

Author(s):

Svetlana A. Glukhova ◽

Vyacheslav S. Molchanov ◽

Boris V. Lokshin ◽

Andrei V. Rogachev ◽

Alexey A. Tsarenko ◽

...

Keyword(s):

3D Printing ◽

Rheological Properties ◽

Shear Thinning ◽

Halloysite Nanotubes ◽

Polymer Chains ◽

Cross Linking ◽

Saxs Data ◽

Nanocomposite Hydrogels ◽

Embedded Network ◽

The Cross

Rapidly growing 3D printing of hydrogels requires network materials which combine enhanced mechanical properties and printability. One of the most promising approaches to strengthen the hydrogels consists of the incorporation of inorganic fillers. In this paper, the rheological properties important for 3D printability were studied for nanocomposite hydrogels based on a rigid network of percolating halloysite nanotubes embedded in a soft alginate network cross-linked by calcium ions. Particular attention was paid to the effect of polymer cross-linking on these properties. It was revealed that the system possessed a pronounced shear-thinning behavior accompanied by a viscosity drop of 4–5 orders of magnitude. The polymer cross-links enhanced the shear-thinning properties and accelerated the viscosity recovery at rest so that the system could regain 96% of viscosity in only 18 s. Increasing the cross-linking of the soft network also enhanced the storage modulus of the nanocomposite system by up to 2 kPa. Through SAXS data, it was shown that at cross-linking, the junction zones consisting of fragments of two laterally aligned polymer chains were formed, which should have provided additional strength to the hydrogel. At the same time, the cross-linking of the soft network only slightly affected the yield stress, which seemed to be mainly determined by the rigid percolation network of nanotubes and reached 327 Pa. These properties make the alginate/halloysite hydrogels very promising for 3D printing, in particular, for biomedical purposes taking into account the natural origin, low toxicity, and good biocompatibility of both components.

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