SYNTHESIS AND RADICAL CROSS-LINKING REACTION OF POLY(VINYLCYCLOPROPANONE ACETAL)S

Synthesis and radical crosslinking reaction of poly (vinylcyclopropano ne acetal)s (4), volume change on the crosslinking, and thermal analys is of 4 and the crosslinked polymers were carried out. 4 was prepared by the reaction of 1,1-dichloro-2-vinylcyclopropane with sodium dialko xides. Radical crosslinking of 4a was carried out in the presence of A IBN, BPO, or DTBP at 60, 80, or 120 degrees C, respectively. 4a afford ed no dichloromethane-insoluble part in the crosslinking in chlorobenz ene but afforded in 37% yield in bulk at 120 degrees C. On the other h and, 4b afforded dichloromethane-insoluble part in 33% yield in the cr osslinking in chlorobenzene at 120 degrees C. Volume shrinkage of 4a a nd 4b on crosslinking at 120 degrees C was 4.11 and 3.55%, respectivel y. Glass transition temperatures of the crosslinked polymers obtained from 4a and 4b were 28 and 163 degrees C, respectively, which were 32 similar to 49 degrees C higher than those before crosslinking. (C) 199 4 John Wiley & Sons, Inc.