Kompozyty poliuretanowe modyfikowane nanocząstkami bemitu

Magdalena Jurczyk-Kowalska

Abstract

In this dissertation original composites, with boehmite particles of nanostructured architecture as the filler and a polyurethane elastomer with 18% of hard segments as the matrix, have been fabricated. Two types of fillers, in the reactions of aluminum oxohydroxide (boehmite) with (a) lactic acid and (b) tributhyl phosphate, were obtained. The final product of the first reaction were carboxyalumoxanes particles, whereas of the second one a mixture of aluminium tri(dibuthylophosphate) and non reacted boehmite particles. Samples of the composites were synthesized in one-step method by in-situ polymerization. Their microstructures have been investigated using scanning electron and atomic force microscopy. Mechanical properties of the composites were evaluated in abrasive wear and tensile tests. Extensive investigations of their thermal properties and flammability were also carried out. The results obtained in this work clearly show that the addition of modified boehmite particles results in: synergic effects of phase separation, segments re-arrangement and formation of paracrystalline structures in polyurethane matrix. The composites containing carboxyalumoxanes particles exhibit better thermal stability of hard segments in the matrix and lower heat emission rate during combustion tests. The composites with aluminium tri(dibuthylophosphate) and non reacted boehmite particles have higher content of crystalline phase. Phosphor atoms in aluminum tri(dibuthylophosphate) particles, modify the structure of polyurethane matrix and lead to an increase of soft segments decomposition temperature and a significant decrease of the rate of heat emission. For both fillers, an increase of emission intensity of thermal degradation volatile products and changes in the reaction route of the matrix decomposition, have been observed. Finally, it should be noted that the fillers employed in this work have not been reported so far in the context of modification of polyurethane elastomers. The original composites reported here, in which fillers are well chemically bonded with polyurethane matrix, are promising materials for applications which require increased flame resistance combined with a good resistance to abrasive wear.
Diploma typeDoctor of Philosophy
Author Magdalena Jurczyk-Kowalska (FMSE)
Magdalena Jurczyk-Kowalska,,
- Faculty of Materials Science and Engineering
Title in PolishKompozyty poliuretanowe modyfikowane nanocząstkami bemitu
Languagepl polski
Certifying UnitFaculty of Materials Science and Engineering (FMSE)
Disciplinematerial sciences and engineering / (technology domain) / (technological sciences)
Defense Date18-06-2010
Supervisor Joanna Ryszkowska (FMSE / DSMP)
Joanna Ryszkowska,,
- Division of Ceramic Materials and Polymers

Internal reviewers Marcin Leonowicz (FMSE / DCFM)
Marcin Leonowicz,,
- Division of Construction and Functional Materials
External reviewers Urszula Narkiewicz - [Instytut Technologii Chemicznej Nieorganicznej i Inżynierii Środowiska (ITN) [Faculty of Chemical Technology and Engineering (WTIICH)]]
Urszula Narkiewicz,,
-
- Instytut Technologii Chemicznej Nieorganicznej i Inżynierii Środowiska
Pages137
Keywords in Englishxxx
Abstract in EnglishIn this dissertation original composites, with boehmite particles of nanostructured architecture as the filler and a polyurethane elastomer with 18% of hard segments as the matrix, have been fabricated. Two types of fillers, in the reactions of aluminum oxohydroxide (boehmite) with (a) lactic acid and (b) tributhyl phosphate, were obtained. The final product of the first reaction were carboxyalumoxanes particles, whereas of the second one a mixture of aluminium tri(dibuthylophosphate) and non reacted boehmite particles. Samples of the composites were synthesized in one-step method by in-situ polymerization. Their microstructures have been investigated using scanning electron and atomic force microscopy. Mechanical properties of the composites were evaluated in abrasive wear and tensile tests. Extensive investigations of their thermal properties and flammability were also carried out. The results obtained in this work clearly show that the addition of modified boehmite particles results in: synergic effects of phase separation, segments re-arrangement and formation of paracrystalline structures in polyurethane matrix. The composites containing carboxyalumoxanes particles exhibit better thermal stability of hard segments in the matrix and lower heat emission rate during combustion tests. The composites with aluminium tri(dibuthylophosphate) and non reacted boehmite particles have higher content of crystalline phase. Phosphor atoms in aluminum tri(dibuthylophosphate) particles, modify the structure of polyurethane matrix and lead to an increase of soft segments decomposition temperature and a significant decrease of the rate of heat emission. For both fillers, an increase of emission intensity of thermal degradation volatile products and changes in the reaction route of the matrix decomposition, have been observed. Finally, it should be noted that the fillers employed in this work have not been reported so far in the context of modification of polyurethane elastomers. The original composites reported here, in which fillers are well chemically bonded with polyurethane matrix, are promising materials for applications which require increased flame resistance combined with a good resistance to abrasive wear.
Thesis file
Jurczyk-Kowalska.pdf 9.93 MB
Citation count*5 (2020-10-22)

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