Synthesis and characterization of copolymers of perfluoro(2-methylene-4,5-dimethyl-1,3-dioxolane) and perfluoro(2-methylene-1,3-dioxolane)

• Perfluorinated ideal random copolymers are synthesized and characterized.
• The copolymers can be amorphous or crystalline depending on the composition.
• The amorphous copolymers are transparent and soluble in fluorinated solvents.
• The Tgs of the copolymers do not change linearly with the composition.
• They are thermally stable (>378 °C) and have low refractive index (1.32–1.34).

Amorphous perfluorinated polymers with outstanding unique properties have established a solid position in various fields, but less costly preparations are required for practical application. Here, copolymers of perfluoro(2-methylene-4,5-dimethyl-1,3-dioxolane) I and perfluoro(2-methylene-1,3-dioxolane) II are synthesized, and the effect of composition on various properties is studied. The copolymers are found to be almost ideal random copolymers with monomer reactivity ratios of r1 = 1.12 and r2 = 1.32. When the amount of II is 0–70 mol%, the copolymers are completely amorphous, optically transparent, and soluble in fluorinated solvents. The glass transition temperatures (Tg) of the copolymers are lower than the sum of the products of the weight fractions of the monomer units and their respective Tg values, suggesting the presence of attractive intermolecular interactions in the homopolymer of I. The copolymers show low refractive indices (1.32–1.34) and high decomposition temperatures (>378 °C), which are comparable with or even better than those of conventional amorphous perfluorinated polymers.

Copolymers of perfluoro(2-methylene-4,5-dimethyl-1,3-dioxolane) I and perfluoro(2-methylene-1,3-dioxolane) II are synthesized, and the effect of composition on various properties is studied. The copolymers are found to be almost ideal random copolymers with monomer reactivity ratios of r1 = 1.12 and r2 = 1.32. When the amount of II was in the range of 0–70 mol%, the copolymers were completely amorphous, optically transparent, and soluble in fluorinated solvents.Figure optionsDownload as PowerPoint slide