Synthesis of poly[oligo(hexafluoropropylene oxide) perfluoroisopropenylether (PIPE)] graft copolymers with vinylidene fluoride (VDF) using CF radicals

• Published in: Polymer chemistry Vol. 1; no. 48; pp. 6651 - 6661
• Main Authors: Burgess, Trevor J, Vitale, Alessandra, Joly-Duhamel, Christine, Bongiovanni, Roberta, Manseri, Abdelatif, Ono, Taizo, Améduri, Bruno, Friesen, Chadron M
• Format: Journal Article
• Published: 10.12.2019
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/c9py01453e

The synthesis of poly(vinylidene fluoride)- graft -oligomeric hexafluoropropylene oxide graft copolymers [poly[VDF- g -oligo(HFPO)-PIPE] is presented, where VDF, HFPO, and PIPE stand for vinylidene fluoride (CH 2 &z.dbd;CF 2 ), hexafluoropropylene oxide (CF 3 CFCF 2 O) and, perfluoroisopropenylether (-OC(CF 3 )&z.dbd;CF 2 ), respectively. First, an 82% isolated yield of oligo(HFPO)-PIPE macromonomer was achieved by using oligo(HFPO) primary iodide as the starting reagent. Then, the radical copolymerization of VDF with the PIPE comonomer, initiated by perfluoro-3-ethyl-2,4-dimethyl-3-pentyl persistent radical (PPFR), was studied under various conditions. The PPFR initiator, stable at room temperature, was able to release a &z.rad;CF 3 radical starting from 80 °C. The resulting poly[VDF- g -oligo(HFPO)-PIPE] graft copolymers were produced in good isolated yields (76 to 97%). The molar percentages and molar masses of such graft copolymers were assessed by 19 F-NMR spectroscopy using the CF 3 - end-group label. The molar percentages of VDF and oligo(HFPO)-PIPE comonomers reached up to 99% and 20%, respectively, while the molar masses ranged between 7500 and 42 600 g mol −1 . Their thermal properties showed: (i) fair to satisfactory thermostability ( T 5% d ) showing up to 271 °C under nitrogen, (ii) glass transition ( T g ) ranged from −81 to −82 °C while (iii) their melting temperature ( T m ) ranged between 150 and 163 °C. Moreover, the synthesized copolymers were demonstrated to be highly omniphobic ( i.e. , simultaneously hydrophobic and oleophobic), showing a water contact angle of ca. 133°, a hexadecane contact angle ca. 70°, and a surface energy as low as 12 mN m −1 . The synthesis of poly(vinylidene fluoride)-graft-oligomeric hexafluoropropylene oxide copolymers [poly[VDF- g -oligo(HFPO)-PIPE] is provided, having glass transitions of ca. −82 °C and respective water and hexadecane contact angles of ca. 133° and 70°.