Effect of Substituents on Cationic Polymerization of Six-Membered Spiro Orthocarbonates

Abstract

ABSTRACT:Six-membered spiro orthocarbonates with methyl substituents were prepared from cyclic dibutylstannyl glycolates and carbon disulfide, then polymerized using boron trifluoride etherate as the catalyst in l,2-dichloroethane at 30°C. The methyl substituent caused a decrease in the polymer yield. The 2,8-dimethyl and 2,4,8,10-tetramethyl spiro monomers were polymerized by a l,10-transfer reaction to bring about polyethercarbonates analogously to the unsubstituted spiro monomer. The spiro-monomer having 3,3,9,9-tetramethyl substituents underwent a 1,10-transfer polymerization at 30°C accompanied with the formation of polycarbonate segment which was partially depolymerized to the corresponding cyclic carbonate monomer at refluxing temperature of 1,2-dichloroethane. Contrary to the above, no polymer was obtained from the 2,2,4,8,8,10-hexamethyl spiro monomer.KEY WORDS Spiro Orthocarbonate / Cationic Polymerization / Transfer Polymerization / Substituent Effect / Polyethercarbonate /

Synthesis, cationic polymerization and curing reaction with epoxy resin of 3,9-di(p-methoxybenzyl)-1,5,7,11-tetra-oxaspiro(5,5)undecane

“…If M-attack takes place, a by-product, 2-(p-methoxybenzyl) propylene carbonate, and polyether are formed. 6 Thus, the peak at 4.1 ppm in Fig 2b should reduce even if only a small portion of polymerization underwent M-attack. N-attack of monomer 2 results in the formation of p-methoxybenzyl substituted oxetane and polycarbonate (see Scheme 2).…”

Synthesis of copolymers containing a spiro orthocarbonate moiety and evaluation of the volume change during their cationic crosslinking

“…One of the best solutions is the use of mono-mers that show no volume shrinkage in their polymerizations. For example, double ring-opening monomers have been developed that are based on spiro orthoester (SOE), [1][2][3][4] bicyclic orthoester, [5][6][7][8][9][10][11][12] and spiro orthocarbonate (SOC) [13][14][15][16][17][18][19][20][21] skeletons; their double ring-opening polymerizations result in no shrinkage or expansion in volume. The volume expansion degrees in the polymerization of SOC derivatives are higher than those for other bicyclic monomers.…”

Matrix‐assisted laser desorption/ionization time‐of‐flight analysis of the copolymerization reaction of an expanding monomer with a diepoxide

“…Several studies have suggested that the polymerization of bicyclic materials such as 1,5,7,11‐tetraoxaspiro[5.5]undecane (TOSU or I ) or its derivatives results in expansion upon polymerization due to a presumed ring opening mechanism in which two bonds break for each bond created 2–12. The homopolymer product formed from unsubstituted TOSU is a linear polymer lacking rigidity and resistance to dissolution in aggressive solvents.…”

“…The homopolymer product formed from unsubstituted TOSU is a linear polymer lacking rigidity and resistance to dissolution in aggressive solvents. Unfortunately, substituents placed on this structure for crosslinking and increased resilience substantially reduce monomer reactivity, presumably because of steric effects 9…”

“…Several studies have suggested that the polymerization of bicyclic materials such as 1,5,7,11tetraoxaspiro [5.5]undecane (TOSU or I) or its derivatives results in expansion upon polymerization due to a presumed ring opening mechanism in which two bonds break for each bond created. [2][3][4][5][6][7][8][9][10][11][12] The homopolymer product formed from unsubstituted TOSU is a linear polymer lacking rigidity and resistance to dissolution in aggressive solvents. Unfortunately, substituents placed on this structure for crosslinking and increased resilience substantially reduce monomer reactivity, presumably because of steric effects.…”