Study on the systhsis and polymerization of 8,9-benzo-2-methylene-1,4,6-trioxaspiro[4,4] nonance (BMTN)

Abstract

8, 9-Benzo-2-methylene-1, 4, 6-trioxaspiro[4, 4]nonane (BMTN) was synthesized by the reaction of phthalide with epichlorohydrin followed by dehydrochlorination. When the radical polymerization of BMTN was carried out by radical initiators such as 2, 2``-azobis(isobutyronitrile) (AIBN), benzoyl peroxide (BPO), and di-t-butyl peroxide (DTBP), BMTN showed quite different polymerization behavior depending on the employed polymerization temperature. In the presence of AIBN as an initiator at 60℃ polymerization was very limited, whereas BMTN was polymerized with DTBP to give a soluble polymer with a high molecular weight and thermal stability. The IR and NMR spectra indicated that the structure of the polymer obtained by DTBP contains aromatic ester and ketone due to the radical ring-opening processes in the backbone. In the radical ring-opening polymerization the increase of polymerization temperature was observed to promote the ring-opening process. $T_g$ and $T_m$ of homopolymer of BMTN by DTBP were, respectively, 98 ℃ and 282 ℃ . BMTN was also polymerized with cationic initiators like boron trifluoride etherate and aluminium chloride to produce a low molecular weight polymer. The copolymerization of BMTN with such vinyl monomers as methyl methacrylate (MMA), acrylonitrile (AN), and maleic anhydride (MA) was readily conducted, but not with styrene in the presence of radical initiators. From the results of thermogravimetric analysis and differential scanning calorimetry it was observed that homopolymers and copolymers with good thermal stability can be obtained by radical ringopening polymerization. The copolymerization of BMTN as an electron donor monomer with AN, MA or nitroethylene (NE) as an electron acceptor gave rise spontaneously to the alternating copolymers by the participation of charge-transfer complexes in the absence of radical initiators. The rate of spontaneous copolymerization was found to be enhanced with increasing solvent polarity and polymeriz...