| 초록 |
PVA is commercially valuable polymer due to its wide applications. These properties of polymer are depends on primary structure like molecular weight and stereoregurarity. PVA is generally produced by free radical polymerization of vinyl acetate (VAc). However, it is very difficult to control of primary structure in free radical polymerization because its low energy barrier between two enantiomers. In this study, we utilized photo-initiated RAFT process to achieve the goal. The RAFT process proceeded well to give polymers with controlled molecular weight and narrow molecular weight distribution. Fluoroalcohol was used to improve stereoregularity of the resulting polymers. It forms hydrogen bonding with carbonyl groups in VAc, and induces a enhanced steric repulsion between two active repeating units. As a result, the prepared PVA showed high content of racemic diad. The detailed polymerization schemes to check the effects of reaction conditions will be discussed. |
