Synthesis and free radical ring‐opening polymerization of 2‐methylene‐4‐phenyl‐1,3‐dioxolane

Abstract

The cyclic ketene acetal, 2-methylene-4-phenyl-1,3-dioxolane (3), was shown to undergo free radical ring-opening polymerization to produce the polyester, poly[y-(8-phenyl)butyrolactone].The monomer 3 was synthesized by an acetal exchange reaction of chloroacetaldehyde dimethyl acetal with styrene glycol in an 87% yield followed by dehydrochlorination of the resulting cisand trans-2-chloromethyl-4-phenyl-1,3-dioxolane (2) with potassium tert-butoxide in tert-butyl alcohol in a 70% yield. 3 was shown to undergo essentially quantitative free radical ring-opening at all temperatures from 60 -150 "C and also nearly complete regioselective ring-opening with cleavage to give the more highly stable secondary benzyl free radical. Even in free radical copolymerization with styrene, methyl methacrylate, vinyl acetate, or 4-vinylpyridine, 3 gives essentially complete ring opening to introduce an ester groups into the backbone of the addition copolymer. The structures of the polymers were established by elemental analysis and 'H and l3C NMR spectroscopy.

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

“…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.…”

Controlled/“Living” Radical Ring-Opening Polymerization of 5,6-Benzo-2-Methylene-1,3-Dioxepane Based on Reversible Addition-Fragmentation Chain Transfer Mechanism

“…For example, when 2-methylene-4-n-decyl-1,3-dioxolane was copolymerized with vinyl chloride, the thermal stability and flexibility of the polymer obtained improved. 15 However, free radical ring-opening polymerization of the unsaturated heterocycles yields polymers with low molecular weight and broad molecular weight distribution. For instance, the radical ring-opening polymerization of 2-methylene-4-phenyl-1,3-dioxolane proceeds via chain radicals 1 and 2 as shown in Scheme 1.…”

“…In the case of 2-methylene-4-phenyl-1,3-dioxolane (MPDO), the ATRP of MPDO yielded a polymer consisted of addition and ring-opening units with well-controlled molecular weight and narrow molecular weight distribution, 32 which is different from its conventional free radical polymerization. 2 How-ever, 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) underwent complete ring-opening polymerization using ATRP initiator system, a polyester with wellcontrolled molecular weight and narrow polydispersity was produced. 33 We want to clarify whether RAFT process can be extended to free radical ring-opening polymerization of unsaturated cyclic acetals.…”

“…KEY WORDS Controlled Polymerization / Radical Ring-Opening Polymerization / Reversible Addition-Fragmentation Chain Transfer (RAFT) / 5,6-Benzo-2-Methylene-1,3-Dioxepane / Free radical ring-opening polymerization has been an attractive subject because it produces polymers with various functional groups (such as ethers, esters, amides, and carbonates) in their backbone. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Addition of unsaturated heterocycles into polymerization system of commercial monomers will improve the properties of the polymers obtained. For example, when 2-methylene-4-n-decyl-1,3-dioxolane was copolymerized with vinyl chloride, the thermal stability and flexibility of the polymer obtained improved.…”