Does the Oxa-Michael Reaction of 2-Trifluoromethacrylic Acid Lead to Original Fluorinated Polyester?

• Published in: Polymer chemistry Vol. 12; no. 31; pp. 4508 - 4523
• Main Authors: Tran-Do, Minh-Loan, Eid, Nadim, Totée, Cédric, Gimello, Olinda, Ameduri, Bruno
• Format: Journal Article
• Language: English
• Published: Royal Society of Chemistry - RSC 10.08.2021
• Subjects: Chemical Sciences; Polymers
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/d1py00685a

2-Trifluoromethacrylic acid (MAF) is a peculiar fluorinated functional monomer. Though it is known to polymerise via C=C bond cleavage under anionic initiation, its oxa-Michael addition polymerisation afforded polyesters bearing trifluoromethyl side groups. This oxa-Michael addition was attempted in the presence of radical (peroxides), basic (amines, phosphines) and acidic (AlCl 3 , triflic acid, ptoluenesulfonic acid) reactants and catalysts which led to oligomers in various yields (up to 57 %) and molar masses (up to 2200 g.mol-1). The obtained polyestes were characterised by GC/MS, IR, 19 F, 1 H and 13 C NMR spectroscopies, MALDI-TOF and their thermal properties were determined by thermogravimetric analysis and differentiel scanning calorimetry. Triphenylphosphine and piperidine led to the highest degree of polymerization DP n (up to 16 th adduct) with a degradation temperature of about 200 °C. The glass transition temperatures (T g) were-59 and-46 °C for MAF bisadduct (diMAF) and oligoMAF, respectively. Such oligomers were hydrophobic, evidenced by water contact angle measurement of 107 ° showing that the contribution of trifluoromethyl group was higher than that of the ester function.