Irreversible and reversible crosslinking of carboxylated acrylonitrile butadiene rubber
Research output: Thesis › Master's Thesis
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Abstract
The present work aims at the development of new crosslinking strategies for carboxylated nitrile butadiene rubber (XNBR) which is used in different fields of applications ranging from seals to gloves. Besides thermal curing approaches with low molecular weight crosslinkers and functional inorganic particles, photochemical routes such as UV induced thiol-ene chemistry were pursued to crosslink XNBR latex. The crosslink kinetics was studied by FTIR spectroscopy whilst the mechanical properties of crosslinked XNBR latex films were characterized by means of tensile testing. The corresponding crosslink densities were determined by equilibrium swelling measurements. The influence of selected key parameters such as crosslinker concentration, reaction time, reaction temperature and UV exposure dose on the tensile strength and elongation at break were studied and optimized. Along with the formation of irreversible crosslinks, a new way of reversible crosslinking of XNBR was established by using the reversible [4πs+4πs] photodimerization of anthracenes. Epoxy-functionalized anthracene derivatives were attached to the XNBR by ring-opening reaction of epoxy-groups with carboxylate moieties of the polymer chains. Anthracene groups undergo a photocycloaddition reaction upon irradiation with UV light (λ > 300 nm) which can be reverted thermally or upon UV irradiation (λ <300 nm). The crosslinking kinetics and reversibility of the photoreaction were studied by means of UV-Vis measurements, light microscopy and confocal microscopy. Based on these studies, the reversibility of the photodimerization could be enhanced considerably by employing hydrogenated XNBR (H-XNBR) and amounted up to 30%.
Details
Translated title of the contribution | Irreversible und reversible Vernetzung von carboxyliertem Acrylnitril-Butadien-Kautschuk |
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Original language | English |
Qualification | Dipl.-Ing. |
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Award date | 27 Mar 2015 |
Publication status | Published - 2015 |