硫化反式聚异戊二烯电子性质的理论化学研究  

Theoretical studies on the electronic properties of vulcanized trans-polyisoprene

作　　者：何丽霞[1] 刘维[1] 王存国[1] 陈辉[1] 孙琳[1] 林琳[1] 

机构地区：[1]青岛科技大学高分子科学与工程学院橡塑材料与工程教育部重点实验室,山东青岛266042

出　　处：《分子科学学报》2007年第3期189-193,共5页Journal of Molecular Science

基　　金：山东省优秀中青年科学家科研奖励基金资助项目(2005BS09002);国家留学归国人员科研启动基金资助项目

摘　　要：应用量子化学计算方法,对反式聚异戊二烯本征态和硫化态结构的能量及电子性质等进行了计算.结果表明,当聚异戊二烯掺杂硫后,相邻两链之间的距离a⊥变窄,体系的总能量降低,从而使整个掺杂体系更加稳定.另外,在硫化聚异戊二烯分子中,S原子位于两个相邻聚异戊二烯链之间,并偏向于其中一个分子链的C C双键的一侧,即与相邻两链中相对应的两个C C双键形成π-p-π共轭体系,增加了电子在两个聚异戊二烯链间的流动性,从而使硫化的反式聚异戊二烯更加稳定.另外,根据固体能带理论,采用量子化学EHMO方法,对反式聚异戊二烯本征态和硫掺杂态的能带结构进行了计算,根据硫化前后能隙和带宽的变化,解释了反式聚异戊二烯掺杂后呈现电导率各向异性的原因.The quantum chemical methods were used to optimize the structure of trans-1,4-polyisoprene （TPI） undoped and doped by sulfur atoms and to study the energies and electronic properties of doped TPI. Here,on the basis of our investigation, the two dimensional （2D） models of the undoped and doped TPI were designed. The calculation results showed that when TPI was doped by sulfur atoms, the distance between two neighboring chains was reaused, resulting in the decrease of energy of the system. Therefore, the doped TPT system got more stable. Moreover, in vulcanized TPI molecular, sul- fur atom was at the position near the double bonds of CH chain,and formed π-p-π conjugated system. That is to say,in the direction perpendicular to the TPI chains, it is the π-p-π conjugative effect that makes the band gap （E,） smaller andelectrons transport easier. This made the vulcanized TPI more stable. In addition, using EHMO quantum chemical method, the band gap and band width of S-doped TPI were studied. On the basis of the calculated results, we explained the reason why doped TPI showed the anisotropic conductivity in parallel and perpendicular to the TPI chains.

关 键 词：反式聚异戊二烯 硫化 电子性质 导电各向异性 量子化学计算 

分 类 号：O641[理学—物理化学]