Free radical ring‐opening polymerization and its use to make biodegradable polymers and functionally terminated oligomers

Abstract

Abstract-Since a carbon-oxygen double bond i s considerably more s t a b l e a n a carbon-carbon double bond, i t has been possible to use t h i s d r i v i n g force to promote free r a d i c a l ring-opening polymerization o f unsaturated heterocyclic compounds. This process, f o r the f i r s t time, has permitted the i n t r o d u c t

Radical Ring-Opening Polymerization: Scope, Limitations, and Application to (Bio)Degradable Materials

“…The polymerization of the 5-membered CKA monomer (CKA1, Figure 68) clearly showed that the formation of polyester increased with an increase of the temperature (50% of ringopening at 60 °C, 83% at 125 °C, 10 and 100% at 160 °C). 183 This trend was observed with other CKA monomers. 181 It has also been shown that addition of a solvent also facilitated the ring-opening, which was explained by favored intramolecular mechanisms (CKA ring-opening in this case), upon dilution.…”

“…Several studies, and in particular Bailey's work, proved the importance of the temperature to facilitate the ring-opening process. The polymerization of the 5-membered CKA monomer (CKA1, Figure68) clearly showed that the formation of polyester increased with an increase of the temperature (50% of ringopening at 60 °C, 83% at 125 °C, 10 and 100% at 160 °C) 183. This trend was observed with other CKA monomers 181.…”

“…The 2-methylene-1,3-dioxolane (CKA1 Figure 72) yielded polymer chains with 83% of ring-opening at 125 °C10 and 87% at 120 °C. 183 At 50 °C, the percentage of ring-opening decreased to 50 %. 11 A slight lower tendency of ring-opening was observed with the 6-membered ring monomer: 2-methylene-1,3-dioxane (CKA17 Figure 72) since 85% of ring-opening were calculated but at 130 °C.…”

“…The first work dealing with the influence of the ring-size on the monomer polymerization was based on the polymerization of 5- to 7-membered ring monomers. The 2-methylene-1,3-dioxolane ( CKA1 Figure ) yielded polymer chains with 83% of ring-opening at 125 °C and 87% at 120 °C . At 50 °C, the percentage of ring-opening decreased to 50% .…”

Controlled Radical Polymerization and Copolymerization of 5-Methylene-2-phenyl-1,3-dioxolan-4-one by ATRP

“…These polymers are therefore degradable upon exposure to an acidic or basic environment or to ultraviolet irradiation. 1,3,7,12,13,16,17 For this reason, CKA and CA polymers are attractive candidates in medical and lithographic applications. 1,12,18 Scheme 2 illustrates the mechanism of radical ringopening polymerization for both the CKA and CA monomers.…”