Synthesis of poly‐ϵ‐caprolactone via a free radical mechanism. Free radical ring‐opening polymerization of 2‐methylene‐1,3‐dioxepane

Abstract

2‐Methylene‐1,3‐dioxepane 6 polymerized with a quantitative ring opening to form poly‐ϵ‐caprolactone via a free radical mechanism. On the other hand, 2‐methylene‐1,3‐dioxolane (ethylene ketene acetal) 4 and 2‐methylene‐1,3‐dioxane 5, under the same conditions, generated polymers with mixed ring‐opened and nonring‐opened structures. In copolymerization monomer 6 also showed a high tendency toward ring opening by which the ester functionality could be conveniently introduced into the backbone of the addition polymers.

BF3�OEt2-initiated polymerization of 2-methylene-1,3-dioxepanes

“…1 Thus, the early reMaterials and Instrumentation search on CKA ring-opening polymerization foSulfuric acid (95-98%), fuming sulfuric acid cused on free radical initiation. 1,[4][5][6][7][8][9] CKAs with (30% free SO 3 ), boron trifluoride etherate, hydrofive-and six-membered rings gave only partial quinone were used as received. Pentane and cycloring opening, 7 while seven-membered rings gave hexane were distilled over Na.…”

“…1,[4][5][6][7][8][9] CKAs with (30% free SO 3 ), boron trifluoride etherate, hydrofive-and six-membered rings gave only partial quinone were used as received. Pentane and cycloring opening, 7 while seven-membered rings gave hexane were distilled over Na. Methylene chloride quantitative opening.…”

Synthesis of Degradable Materials Based on Caprolactone and Vinyl Acetate Units Using Radical Chemistry

“…[1][2][3][4][5][6][7] A less known route to the formation of poly(caprolactone), first shown by Bailey et al 8 and later followed by some others, 9,10 is by radical ringopening polymerization of 2-methylene-1,3-dioxepane (MDO). 2-methylene-1,3-dioxepane is an interesting cyclic ketene acetal monomer giving poly("-caprolactone) (PCL), on the radical-ring-opening homopolymerization (RROP) and can introduce ester groups onto the vinyl polymer backbones during copolymerizations with vinyl monomers.…”

“…is reported by us 11-18 and others. 10,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] The main problem during the copolymerization is the huge reactivity difference between the CKA and the vinyl monomers leading to either low molecular weight homo vinyl polymers without ester linkages or copolymers incorporating only low amounts of the comonomers with block structure, incomplete ring-opening or no ring-opening at all.Keeping in view our broad aim of making new degradable materials with new properties based on the conventional plastics, here an attempt has been made to study the copolymerization behaviour of vinyl acetate (VAc) and MDO under conventional radical polymerization conditions. The resulting materials depending upon the glass transition temperatures could be proposed for further studies as degradable gums, coating materials, adhesives etc.…”

“…is reported by us [11][12][13][14][15][16][17][18] and others. 10,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] The main problem during the copolymerization is the huge reactivity difference between the CKA and the vinyl monomers leading to either low molecular weight homo vinyl polymers without ester linkages or copolymers incorporating only low amounts of the comonomers with block structure, incomplete ring-opening or no ring-opening at all.…”