材料期刊网

在以Gilch路线合成了一系列含烷氧基超支化聚对苯撑乙烯（HPPV）共聚物的基础上,对其聚合反应的过程及机理进行了初步研究。通常,PPV的聚合是按照自由基机理进行,即反应物单体在分子内脱去卤化氢（HX）后形成一种对醌二甲烷单体,再通过自由基链增长达到聚合的目的。通过DFT（B3LYP/6-311G（d））方法对反应单体1,3,5-三氯甲基-2,4,6-三甲氧基苯（TCMTMOB）在分子内脱去HCl后的结构进行了优化,发现此单体同样可以形成稳定的间二醌结构,易于与对醌二甲烷单体共聚生成超支化共聚物,这与实验结果相吻合。

Based on the synthesis of a series of hyperbranched PPVs via Gilch polymerxzatlon, the polymermauon mechanism was discussed. It is a broad consensus that in Gilch polymerizations the 1,4-bis（halomethylene）ben- zene starting material first changes into an α-halo-p-quinodimethane intermediate which then acts as the real ac- tive monomer in the subsequent radical chain polymerization. In this copolymerization reaction, the branched unit cannot be eliminated to form a p-quinodimethane intermediate. The plausible route is a trigonal trianion acting as initiator for an anionic polymerization, If the copolymerization reaction is processed in radical mecha- nism, it is the key step to form a stable a-halo-m-quinodimethane in the copolymerization. In order to verify the existence and stability of α-halo-m-quinodimethane intermediate, the molecular geometry of 1,3,5- trichlorom- ethyl -2,4,6- trimethyloxybenzene （TCMTMOB） were optimized by DFT methods （B3LYP/6-311G（d））. The results show that the monomer TCMTMOB can eliminate HC1 to give a stable α-halo-m-quinodimethane struc- ture; the negative charges on quinodimethane are increased because of the electron-donating effect of the alkoxy groups in the ring, which is in favor of the stability of the corresponding exocyclic double bonds. The interme- diate represent the initiators of subsequent bilateral radical chain growth via 1,6-type addition of further p- quinodimethane monomers to form a hyperbranched copolymer. So, the theoretical analysis agrees well with experiment result.