Synthesis and Cationic Polymerization of Multifunctional Vinyl Ethers Containing Dipolar Electronic Systems

摘要

2,4-Di-(2`-vinyloxyethoxy)benzylidenemalononitrile (la), methyl 2,4-di-(2`-vinyloxyethoxy)benzylidenecyanoacetate (lb), 3,4-di-(2`-vinyloxyethoxy)benzylidene malononitrile (2a), methyl 3,4-di-(2`-vinyloxyethoxy)benzylidenecyanoacetate (2b), 2,5-di-(2`-vinyloxyethoxy)benzylidenemalononitrile (3a), methyl 2,5-di-(2`-vinyloxyethoxy)benzylidenecyanoacetate (3b), 2,3-di-(2`-vinyloxyethoxy)benzylidenemalononitrile (4a), and methyl 2,3-di-(2`-vinyloxyethoxy)benzylidenecyanoacetate (4b) were prepared by the condensation of 2,4-di-(2`-vinyloxyethoxy)benzaldehyde, 3,4-di-(2`-vinyloxyethoxy)benzaldehyde, 2,5-di-(2`-vinyloxyethoxy) benzaldehyde, and 2,3-di-(2`-vinyloxyethoxy)benzaldehyde with malononitrile or methyl cyanoacetate, respectively. Trifunctional divinyl ether monomers 1-4 were polymerized readily with boron trifluoride etherate as a cationic initiator to give optically transparent swelling poly(vinyl ethers) 5-8 havina oxybenzylidenemalononitrile and oxycyanocinnamate, which is presumably effective chromophore for second-order nonlinear optical applications. Polymers 5-8 were not soluble in common organic solvents such as acetone and DMSO due to crosslinking. Polymers 5-8 showed a thermal stability up to 300 ∩ in TGA thermograms, which is acceptable for electrooptic device applications.