摘要
采用两性离子型的催化剂Rh+[η-C6H5(nbd)B-(C6H5)3]实现了含手征性中心和硫代乙酸酯基的苯乙炔单体的聚合,用红外光谱、核磁共振氢谱和紫外-可见吸收光谱表征了聚合物的结构,证实得到了预期产物.聚合物的重均分子量达到了73200,在氯仿、四氢呋喃、二氯甲烷等有机溶剂中有良好的溶解性能.聚合物热稳定性高,在氮气氛围下热分解温度为336℃,在900℃的高温下有31%的重量残留.用扫描电子显微镜观察发现,在浓度为5.0mg/mL的聚合物氯仿溶液形成的薄膜中有微米长度的棒状有序结构;由浓度为0.5mg/mL的聚合物氯仿稀溶液形成的薄膜表面有晶体析出.用透射电子显微镜观察聚合物在氯仿溶液中缓慢形成的微结构,发现当浓度高于1.0mg/mL时,聚合物在碳膜上形成铺展的薄膜,薄膜由纳米尺寸的丝带状结构取向排列而成;当浓度低于0.5mg/mL时,聚合物形成具有规则几何形态的微晶体.在聚合物热稳定性的显著提高和有序微结构的形成过程中,聚苯乙炔侧链中的手征性中心发挥了关键的作用.
Polymerization of a phenylacetylene monomer containing chiral center and thiolacetate was achieved by using a zwitterionic rhodium complex or Rh＋[η-C6H5（nbd）B-（C6H5）3] as catalyst. Chemical structure was characterized with infrared （IR）, nuclear magnetic resonance （NMR）, UV-Vis absorption spectroscopic techniques, and the experimental data confirmed the formation of the expected polymer. The obtained polymer was soluble in common organic solvents such as chloroform, dichloromethane, tetrahydrofurran, and its weight-average molecular weight was about 7.32 × 10^4. The polymer was highly thermally stable; it lost 5% of its original weight at a temperature of 336℃, and about 31% residual weight was measured at 900℃. SEM images showed that rod-like ordered entities were observed for the thin film fabricated by casting polymer solution （a concentration of 5.0 mg/mL in chloroform ） under ambient condition; while crystallites were observed when dilute polymer solution （a concentration of 0.5 mg/mL in chloroform） was used to film fabrication. As revealed by TEM images, when the evaporation rate was controlled to be slow and the concentration of polymer in chloroform was higher than 1.0 mg/ mL,a polymer layer spread on the carbon supporting film on copper micro-grid; when polymer concentration was lower than 0.5 mg/mL, microcrystallites with the improvement of the thermal stability and regular shapes were observed. Based on the macromolecular structure, the formation ordered microstructure can be tentatively ascribed to the role of chiral centers on the side chains of the resulted polyphenylacetylene.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
2009年第10期1031-1036,共6页
Acta Polymerica Sinica
基金
国家自然科学基金(基金号20634020
50573065)
国家重点基础研究发展计划(973计划
项目号2002CB613401)资助
关键词
官能化聚炔
手性中心
有序
热稳定性
Functional polyacetylenes
Chiral center
Ordered structure
Thermal stability
