Radioactive ion implantation of thermoplastic elastomers


Première édition

The radioactive ion implantation wear measuring method (RII) has been used for many years as a tool to make highly sensitive real-time in-situ measurements of wear and corrosion in metallic or ceramic materials. The method consists of the controlled implantation of radioactive ions of limited decay time in a thin layer at the surface of the material. The progressive abrasion of the material results in a decline in radioactivity which is followed to monitor material losses.

The application of RII to control the wear of polymers is potentially of interest, but it has been lagging behind because of uncertainties related to possible changes in material properties during and after the implantation, and to the exact shape of implantation profiles. In this thesis, we investigate these issues on two thermoplastic elastomers, among which one contains radiation-sensitive unsaturated bonds, using as ions 7Be, 7Li and Kr. The results of the sample characterisation indicate that the 7Be and 7Li implantations, under properly-selected conditions, do not induce significant modifications in the materials. The implantation of a stack of polymer thin films and the activity measurements performed to determine the implantation profile are also presented. The experimental results on the ion implantation profiles and the determination of calibration curves are presented and discussed in comparison with simulated results. The results indicate that it is possible to predict the implantation profile by means of simulations. This bodes well for the application of the RII method to polymer materials.

An experimental study is presented regarding the possible redistribution of the implanted 7Be after implantation. Since very few existing experimental techniques are able to detect light elements implanted in polymer targets at fluences less or equal to 1012 cm-2, with implantation depths of a few µm, a new method is presented, which implies the use of plasma etching techniques in order to remove layers of polymers and measuring the remaining activity after each step. Our results indicate that a redistribution of the implanted ions takes place during the implantation process, resulting in a scrambling of the initial implantation profile. Nevertheless, provided a suitable methodology be used, wear measurements in polymers by using the RII method are still possible, as we propose in the thesis.


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Spécifications


Éditeur
Presses universitaires de Louvain
Partie du titre
Numéro 204
Auteur
Veronica Borcea,
Collection
Thèses de l'École polytechnique de Louvain
Langue
anglais
BISAC Subject Heading
TEC000000 TECHNOLOGY & ENGINEERING
Code publique Onix
06 Professionnel et académique
CLIL (Version 2013-2019 )
3069 TECHNIQUES ET SCIENCES APPLIQUEES
Date de première publication du titre
2008
Subject Scheme Identifier Code
Classification thématique Thema: Technologie, ingénierie et agriculture, procédés industriels
Type d'ouvrage
Thèse

Livre broché


Date de publication
01 janvier 2008
ISBN-13
978-2-87463-127-6
Ampleur
Nombre de pages de contenu principal : 184
Code interne
78631
Format
16 x 24 x 1,1 cm
Poids
306 grammes
Prix
16,00 €
ONIX XML
Version 2.1, Version 3

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Sommaire


CHAPTER I GENERAL INTRODUCTION 1
1. Context 1
2. Wear of polymer materials 2
2.1. Classification 2
2.2. Two case studies: 3
2.2.1. The weathering of polymer coatings 3
2.2.2. The abrasive wear of polymers 8
2.3. Common wear measuring methods 12
3. Wear measurement using Radionuclide Techniques 12
3.1. Activation of materials 14
3.1.1. Activation based on nuclear reactions induced in the wear parts 14
3.1.2. Radioactive Ion Implantation 16
3.1.3. Calibration curves 17
3.2. Wear measurement methods 18
3.2.1. Concentration method 18
3.2.2. Difference method 19
3.3. Advantages over other wear measuring methods and applications 21
3.4. Radionuclide techniques and polymers 22
4. Thermoplastic elastomers 23
4.1. General considerations 23
4.2. Industrial applications 25
4.3. The SEPS block copolymer (Hybrar 7125) 26
5. Thesis overview 28
6. References 31
CHAPTER II ION IMPLANTATION – SOME THEORETICAL CONSIDERATIONS 39
1. Introduction 39
2. Interactions between ion beams and polymers: ion irradiation and ion implantation 40
2.1. Phenomena and specific parameters 40
2.1.1. Energy loss mechanisms 40
2.1.2. Stopping power 42
2.1.3. Range and range straggling 45
2.2. Physico-chemical modifications 46
2.2.1. Primary phenomena 46
2.2.2. Parameters influencing physico-chemical modifications 49
2.2.3. Macroscopic modifications 54
3. Redistribution of the implanted ions 55
3.1. Possible experimental techniques 56
3.2. Bibliographic review of experimental results and theoretical aspects 58
4. Radioactive ion implantation, the special case of radioactive emissions 60
4.1. The radioactive decay 60
4.2. 7Be radioactive decay 62
4.3. Electromagnetic radiation and matter 63
5. References 66
CHAPTER III BE7 ION IMPLANTATION IN POLYMERS - EXPERIMENTAL IMPLANTATION PROFILE 77
1. Introduction 77
2. Experimental section 78
2.1. Copolymer foils preparation 78
2.2. Energy degraders thickness measurement 79
2.3. Experimental and simulated energy distributions 82
2.4. Ion implantation in SEPS foils 83
2.5. Activity measurements 84
3. Results and discussion 84
3.1. Energy degraders thickness measurement 84
3.2. Experimental and simulated energy distributions 86
3.3. Experimental stopping power of 7Be ions in aluminium 90
3.4. Implantation profile of Be7in SEPS 93
4. Conclusions 101
5. References 102
CHAPTER IV PHYSICO-CHEMICAL MODIFICATIONS OF ION IMPLANTED POLYMER 103
1. Introduction 103
2. Experimental section 104
2.1. Copolymer films preparation 104
2.2. Ion implantations 104
2.2.1. 7Be and 7Li ion implantation 104
2.2.2. Kr ion implantation 105
2.3. Exposure to the radioactive emission 106
2.4. Characterisation techniques 106
2.4.1. Optical microscopy 106
2.4.2. Atomic Force Microscopy 107
2.4.3. Fourier Transform Infrared Spectroscopy 107
2.4.4. X-ray Photoelectron Spectroscopy 108
3. Results and discussion 108
3.1. 7Be and 7Li ions – implantation and radioactive emission 108
3.1.1. Optical microscopy 108
3.1.2. Atomic force microscopy 108
3.1.3. Fourier Transform Infrared Spectroscopy 109
3.1.4. X-ray Photoelectron Spectroscopy 114
3.2. Kr ion implantation 114
3.2.1. Optical microscopy 116
3.2.2. Atomic force microscopy 118
3.2.3. Fourier Transform Infrared Spectroscopy 120
3.2.4. X-ray Photoelectron Spectroscopy 123
4. Conclusion 127
5. References 128
CHAPTER V IMPLANTED 7BE IONS DIFFUSION IN SEPS COPOLYMER 131
1. Introduction 131
2. Plasma etching 133
2.1. Generalities 133
2.2. Plasma etching of polymers 133
2.2.1. Plasma parameters influencing the etching rates of polymers 135
2.2.2. Etching rate versus chemical structure 137
2.2.3. Etching rate versus physical properties 137
3. Experimental section 138
3.1. Copolymer films preparation 138
3.2. Ion implantation 138
3.3. Plasma etching 139
3.4. Radioactivity measurements 140
3.5. Thickness measurement by ellipsometry 141
3.6. AFM 141
4. Results and discussion 141
4.1. Etching rates 141
4.2. Roughness 145
4.3. Diffusion of the implanted ions 150
5. Conclusion 154
6. References 156
CONCLUSIONS AND PERSPECTIVES 161
ANNEXE A ION IMPLANTATION EXPERIMENTS 165
ANNEXE B CORRECTING FOURIER TRANSFORM INFRARED SPECTROSCOPY (FT-IR) SPECTRA 167