| Research Abstract |
We have developed new methodology for synthesizing telechelic polymers with hydroxy, amino, carboxy, mercapto, and 1,3- butadienyl groups. The methodology involves the reaction of anionic living polymers from styrene, 1,3-butadiene, and isoprene with haloalkyl compounds with protected functional groups. The resulting polymers all were observed to possess controlled molecular weights and narrow molecular weight distributions. More importantly, the degrees of functional groups are quantitatively introduced by the above reactions. The analyses of end functional groups were successfully performed by NMR, IR, UV, and the newly developed TLC-FID methods. These functional groups could be transformed into more reactive acid anhydride, acid chloride, and chloroformate moieties. Similarly, the synthesis of telechelic polymers using cationic living polymers are under investigation at the present time.
In order to make multi-block copolymers with well-defined structures, a model reaction between aminated polystyrene and carboxylated polyisoprene was carried out. The reaction was found to proceed quantitatively to produce the corresponding block copolymer. The similar reactions on polystyrene gel have been carried out followed by elimination from the gel to afford the block copolymers in high yields more than 90%. The well-defined multi-block copolymers are now attempted to synthesize by sequential addition of different telechelic polymers on polystyrene gel.
|
