Polymers in strong magnetic fields
Triggering chemical reactions across polymer-polymer interfaces
Polymer composites are of great importance in the development of new synthetic materials. Important is the knowledge about molecular processes and interactions between different polymers in order to obtain materials with tailored and outstanding properties. In terms of long term stability and high mechanical stability the formation of covalent bonds between different polymers are of high impact. However, there are a number of restrictions for the formation of such bonds between polymers. Reactive additives or special interface layers have to be introduced for bonding polymers. However these additives may lead either to unwanted properties of the material.
The aim of project is focused on the triggering of chemical reactions between poly-mers. When small metal particles, embedded in the polymer-polymer interface, ex-posed to high magnetic field pulses an Eddy current heating occurs. The local ele-vated temperature triggers chemical reactions between functional groups of two dif-ferent polymers. The major advantage is that the increased temperature is limited to the polymer-polymer interface.
Reactive Welding of polymers - new materials
The welding process between two or more different polymers is initiated by local heating of metal particles due to Eddy current caused by very short but strong mag-netic pulses. Since the metal particles are placed in the polymer-polymer interface bulk material will be not heated. The magnetic pulse welding initiated also the for-mation of covalent bonds so that new types of materials with high performance fea-tures can be produced.
- Helmholtz-Zentrum DresdenRossendorf, Hochfeld Magnet-Labor
- Technische Universität Dresden, Medizinische Fakultät Carl Gustav Carus, Klinisches Sensoring und Monitoring
- Vilnius University, Lithuania, Department of General Physics and Spectroscopy
"Cold" boundary layer reactions
Low-interaction transfer of energy into the interior of the material. Initiation of chemical reactions. Processing without heating the bulk volume. Processing of bio- or renewable macromolecules. No material class-dependent shrinkage after coupling.
Biopolymers or biopolymer composites are preferable to polymer materials made from fossil raw materials from the point of view of environmental compatibility and sustainability. When using composites or hybrid construction, the interfacial layers make a decisive contribution to the material properties. Targeted interfacial engineering and powerful analytical methods are required.
In the case of thermally unstable or hydrate-shell-stabilised biopolymers, conventional processing at high temperatures is out of the question. Heating the bulk volume for processing causes irreversible destruction of the molecular structures. Instead, the goal must be to introduce the processing energy specifically into the interfaces. Without interaction with the bulk material, undesirable processes such as discolouration, shrinkage or chain degradation do not occur.
Development of processes for "cold" boundary layer reaction.
Chemical coupling in magnetic high fields
Magnetic high fields with field strengths of up to 70 T and are used at low frequency for energy input into the boundary layers.
Application, e.g. chemical bonding/debonding of thermolabile materials, such as hydrogels or biopolymers also as solid-phase conversions.
High-frequency fields for initiating chemical reactions
If electromagnetic transducers are placed in the boundary layer, a locally limited energy absorption of an electromagnetic high-frequency field can be achieved.
Application, e.g. chemical boundary layer reaction, chain fission generates a second inner phase, chain growth - cross-linking of biopolymers at s-l interfaces in the aqueous system (energy input in the terahertz frequency range).