Synthesis of Phosphonated Oligomers and Layer by Layer Assembly for Flame Retardant applications on cotton or on PU foams

摘要

The work focuses on the synthesis and layer by layer assembly of oligoamines and phosphonated oligoamine. To this aim, 2 generations of oligoamines under the phosphonated form have been obtained in aqueous media: the first generation has a vinyl backbone and the second one is based on a chitosan structure. Firstly, radical polymerization of acid salt of allylamine was performed and characterized by size exclusion chromatography. Phosphorus-containing oligoallylamines had a number-average molar mass ranging from 4500 to 20,000 g.mol~(-1). Secondly, native chitosan was depolymerized via microwaves to obtain low molar masses and post-fonctionalized via Kabachnik-Field reaction. Multilayered films were prepared by the dipping method in a solution of polyanion then a solution of polycation. Then, thermogravimetric analyses of the LbL assembled polymers showed both high thermal and thermo-oxidative stabilities. Lastly, the flame retardancy tests were successfully made on different substrates (cotton fabrics or PU foams) and the influence of nature and molecular weight of oligomers were discussed in term of ignifugation efficiency.