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- Preparation of flame resistant polymers (Dr. Manuela List)

Sorry, this page is currently not available in English. Below you will find the contents in German.

Polyethylene is the most widely used plastic in the world. The properties of polyethylene can be modified and enhanced by copolymerization with higher ɑ-olefines. The most important ones are butene (C4), hexene (C6) and octene (C8). Ethylene can also be copolymerized with a wide range of non-olefinic monomers. Common examples are ethylene-vinyl-acetate copolymer (EVA) and different ethylene-acrylate copolymers.
A method to increase the flame resistance of polyolefines is the addition of nitrogen compounds (e.g. melamine, melamine-cyanurate, trihydrazinotriazine, etc.), halogen compounds or inorganic fillers. In most cases these compounds are added after the polymerization process to the polymer. However, this may lead to problems (e.g. melamine partly migrates to the surface; melamine-cyanurate tends to sublime and foam the polymer; etc.).

The research group’s interest is focused on the incorporation of different nitrogen based heterocyclic systems (e.g. melamine based materials, imidazole derivatives,…) primarily with ethylene via copolymerization to circumvent the above mentioned problems. Not only the copolymerization with ethylene has to be tested, also ionic- and radical polymerization with e.g. styrene, different acrylates will be investigated.
Depending on the used monomers, basic polymerization parameters such as the type of catalyst, concentrations of reactants, temperature, solvent, reaction time, and the way of adding the nitrogen compound are studied and optimized.

Another important field of research is the characterization of these novel products. For this purpose a wide variety of analysis methods are used (elemental analysis, IR-, and Raman spectroscopy, DSC, TGA, pyrolysis-GC/MS, GPC, Maldi-Tof,…).

Pyrolysis-GC/MS of a tetramethyldivinylmelamine-ethylene-copolymer

Furthermore, the copolymers are evaluated with the respect to their flame resistance and their mechanical properties.

Flame resistance of polyethylene and different ethylene-vinylmelamine copolymers