초록 |
Recently, Polyvinylsilazane (PVSZ) is used as the well known preceramic polymer for SiCN and/or Si3N4 ceramic materials. Because of its excellent thermal stability, good thermal conductivity, good chemical properties and oxidation resistance, PVSZ find widespread applications in many technologies. Microwave-Assisted synthesis has long been known to accelerate thermal reactions and there exist many literature examples whereby microwave reactors have been used in conventional free-radical polymerizatio. High molecular weight and high conversion Polyvinylsilazane have been successfully synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization in toluene at temperature 120oC, using microwave method. The conversion of Polyvinylsilazane with 81.7% was readily controlled to obtained the molecular weight 5911 with narrow polydispersity <1.5. The resulting polymer showed a high ceramic yield of 71% at 1000oC. Interestingly, the polymerization time of Polyvinylsilanzane has reduced by the use of microwave heating, compared to conventional heating. |