THE CHEMISTRY OF FLUORINATED DIOXOLES AND DIOXOLANES .5. STRUCTURE-PROPERTY RELATIONSHIP OF FLUORINATED DIOXOLE POLYMERS

Teflon-AF, based on the perfluoro-2,2-dimethyl-1,3-dioxole monomer (1), is a new class of high-T(g) amorphous fluoroplastics with enhanced properties over traditional fluoropolymers. New monomer and polymer chemistry that relates to fluorodioxole molecules was explored. Synthetic methods for introducing different substituents at 2-, 4-, and 5-positions of the dioxole ring were developed. The structure-property relationships of these polymers were studied, and we have found that the polymer glass transition temperatures are highly sensitive toward the structure of these monomers. The results indicated that the steric bulkiness of the substituents on the dioxole ring is critical for polymer properties, not only in the determination of glass transition temperature but also on the rate of polymerization. A rationalization is proposed to explain these observations.