Synthesis and characterization of novel cyclomatrix-type poly(organophosphazene) colloids
- Synthese und Charakterisierung neuartiger cyclomatrix Poly(organophosphazen) Kolloide
Kühl, Sebastian Michael Josef; Pich, Andrij (Thesis advisor); Möller, Martin (Thesis advisor)
Dissertation / PhD Thesis
Dissertation, RWTH Aachen University, 2019
Colloid systems based on cyclomatrix-type poly(organophosphazene) polymers have received increasing attention in recent years as they combine the high synthetic flexibility of poly(organophosphazene) polymers as well as their outstanding properties with the field of colloid chemistry and related applications. Although these materials generally exhibit promising properties, such as high thermal stability, flame retardant properties, biodegradability and biocompatibility, and despite their high potential for application in various fields, the number of publications referring to these materials is still low. Regarding this, the aim of this work is the synthesis and investigation of novel cyclomatrix-type poly(organophosphazene) colloid systems with a special focus on new properties and applications. In the first part of this work, two novel cyclomatrix-type poly(organophosphazene) colloid systems on basis of hexachlorocyclotriphosphazene (HCCTP) and the aliphatic amine crosslinkers hexamethylenediamine (HMDA) or branched polyethyleneimine (bPEI), respectively, are studied. Both systems are prepared via precipitation polycondensation in acetonitrile in the presence of triethylamine and can be effectively tuned in size through the application of the steric stabilizer polyvinylpyrrolidone (PVP) as well as the reactant concentration adjusted in the feed. Through an additional introduction of non-crosslinking reactants, namely ethylenediamine (EtDA) or 2-dimethylaminoethylamine (DMEN), microgels with adjustable crosslinking density are accessible. Further, when amino-functionalities are applied in excess in the syntheses, amino-functional microgels, which are open to post-modification reactions, can be obtained. Finally, the potential application of both microgel systems as flame-retardant finishing for cotton fibres is investigated with a special focus on coating methods and flame-retardant properties.The second part of this work addresses the synthesis and investigation of degradable cyclomatrix-type poly(organophosphazene) colloid systems. For this purpose, two approaches are investigated, one of which based on the incorporation of hydrolysable glycine ethyl ester side groups into the cyclomatrix structure of PVP-stabilized poly(HCCTP-co-HMDA) colloids, while the other involves the application of two inherently degradable glycine ester crosslinkers. In the latter case, poly(organophosphazene) colloids, which show good degradability in acid and basic aqueous media, are obtained.