A NOVEL CROSS-LINKING-DECROSSLINKING SYSTEM OF POLYMERS HAVING SPIRO ORTHOESTER MOIETIES IN THE SIDE-CHAINS

Acid-catalyzed reversible crosslinking-decrosslinking of polymers havi ng spiro orthoester groups in the side chains was carried out. The cop olymers obtained by the radical copolymerizations of 2-methylene-1,4,6 -trioxaspiro[4.6] undecane with acrylonitrile, methyl, cyclohexyl, and 2-ethylhexyl acrylates were treated with trifluoroacetic acid (5 mol% ) at -10 degrees C for 1 h in CH2Cl2 (4.2 M) to afford the crosslinked polymers in 69-99% yields. The crosslinked polymers were then treated with trifluoroacetic acid at a low concentration (0.1 M) in CH2Cl2 at room temperature for 1 h to give the original polymers in 55-99% yiel ds. These results strongly support the conclusion that the acid-cataly zed reversible crosslinking-decrosslinking of the polymers possessing the spiro orthoester groups in the side chains could be constructed.