TY - BOOK

T1 - Design of Smart Elastomers with Tailored Network Architecture

T2 - From Advanced Crosslinking Strategies towards Stimuli-Responsive Materials with Spatially Resolved and Switchable Characteristics

AU - Manhart, Jakob Cornelius

N1 - embargoed until 12-09-2022

PY - 2017

Y1 - 2017

N2 - The present study addresses advanced crosslink strategies for carboxylated nitrile butadiene rubber that is used for the production of various elastomer articles (e.g. medical technology, petrol and automotive industry). In contrast to state-of-the-art procedures, two strategies are pursued that are based on thermal and photochemical reaction initiation mechanisms and feature an enhanced production and energy efficiency. Newly developed thermal procedures lead to irreversible crosslinked elastomers that exhibit excellent mechanical properties as well as low amounts of residual chemicals, leading to high skin compatibility. The impact of crucial key parameters (e.g. reaction time, reaction temperature and crosslinker concentration) on the property characteristics of the elastomer are studied and the process parameters are accordantly optimized for an implementation on the industrial scale. In addition to the generation of irreversible network sites, the second approach aims at the selective integration of reversible crosslink points capable of undergoing repeated cleavage and crosslink reactions in response to an external stimulus (e.g. light or heat). The generation of those switchable elastomeric networks is based on a side chain modification of the carboxylated rubber by the attachment of epoxy functional anthracene derivatives. Curing of the modified rubber is accomplished upon illumination with long wave UV-light (λ>300nm), exploiting the reversible [π4s+π4s]-photodimerization of the anthracene pendant groups. Due to the reversible nature of the photodimerization reaction, the photodimers can be cleaved again through exposure to short wave UV-light (λ

AB - The present study addresses advanced crosslink strategies for carboxylated nitrile butadiene rubber that is used for the production of various elastomer articles (e.g. medical technology, petrol and automotive industry). In contrast to state-of-the-art procedures, two strategies are pursued that are based on thermal and photochemical reaction initiation mechanisms and feature an enhanced production and energy efficiency. Newly developed thermal procedures lead to irreversible crosslinked elastomers that exhibit excellent mechanical properties as well as low amounts of residual chemicals, leading to high skin compatibility. The impact of crucial key parameters (e.g. reaction time, reaction temperature and crosslinker concentration) on the property characteristics of the elastomer are studied and the process parameters are accordantly optimized for an implementation on the industrial scale. In addition to the generation of irreversible network sites, the second approach aims at the selective integration of reversible crosslink points capable of undergoing repeated cleavage and crosslink reactions in response to an external stimulus (e.g. light or heat). The generation of those switchable elastomeric networks is based on a side chain modification of the carboxylated rubber by the attachment of epoxy functional anthracene derivatives. Curing of the modified rubber is accomplished upon illumination with long wave UV-light (λ>300nm), exploiting the reversible [π4s+π4s]-photodimerization of the anthracene pendant groups. Due to the reversible nature of the photodimerization reaction, the photodimers can be cleaved again through exposure to short wave UV-light (λ

KW - Elastomer

KW - Vernetzung

KW - Photochemie

KW - Anthracen

M3 - Doctoral Thesis

ER -