Telechelic
Telechelics are oligomers with an approximate molar mass of approx. 2000 g / mol and controllable functional end groups . Common functional end groups are -CH = CH, -NCO, -OH, -COOH, and -SH. Telechelic are u. a. obtained by the termination of anionic polymerizations with certain reagents . Further possibilities for representation are polycondensation , whereby one component must be present in a certain excess, quantitative conversion must be ensured and side reactions must be excluded, radical polymerization , cationic polymerization , chain cleavage and criss-cross cycloaddition.
Advantages of telechelic substances over higher molecular weight substances are a lower viscosity and, as a result, better mixing and homogenizing properties, etc. a. of additives, compared to monomers a significantly lower toxicity, the possibility to work solvent-free in the case of further reactions and a lower specific heat development in further reactions. By using different telechelics and monomers, a wide range of products can also be tailor-made.
Individual evidence
- ↑ a b c Oskar Nuyken: Tailored Polymers: Synthesis Strategies for Telechelic, Macromonomers, Block and Graft Copolymers . In: Applied Macromolecular Chemistry . tape 223 , no. 1 , 1994, p. 29-46 , doi : 10.1002 / apmc.1994.052230103 .
- ↑ Koltzenburg, S .; Maskos, M .; Nuyken, O .: Polymers: Synthesis, Properties and Applications . 1st edition. Springer Spectrum, Heidelberg 2014, ISBN 978-3-642-34772-6 , p. 279 .