聚苯乙烯微球负载脲催化剂与碱协同催化环内酯的开环聚合

通过环己基异氰酸酯和4-三氟甲基苯异氰酸酯分别与氨基化聚苯乙烯反应, 构筑了聚苯乙烯(PS)负载的环己基脲(PS-U₁)和聚苯乙烯负载的4-三氟甲基苯基脲催化剂(PS-U₂). 利用PS-U/KOMe二元催化体系协同催化环内酯的开环聚合. 结果表明, PS-U/KOMe二元体系可高效催化ε-己内酯(ε-CL)、 δ-戊内酯(δ-VL)和L-丙交酯(L-LA)的开环聚合, 制备了低催化剂残留且环境友好的聚酯材料; 同时实现了PS-U的回收及循环利用.

Ring-opening Polymerization of Cyclic Esters Using Recyclable Polystyrene Supported Urea-Base Binary Catalyst

To solve the catalyst residual problem， a promising strategy is to immobilize active catalyst on the surface of polymer microspheres to make heterogeneous catalyst. Herein， a metal-free approach to the ring-opening polymerization of lactones using recyclable polystyrene supported urea-potassium methoxide binary catalyst system is described. The new heterogeneous catalysts， polystyrene（PS）-supported cyclohexyl urea （PS-U₁） and polystyrene-supported 4-（trifluoromethye） phenyl urea（PS-U₂）， were prepared by reactions of amine-functionalized PS microspheres with cyclohexyl isocyanate and 4-（trifluoromethyl）phenyl isocyanate， respectively. It was found that PS-U-potassium methoxide catalytic system exhibited high catalytic activity for ring-opening polymerization（ROP） of lactones， including ε-caprolactone（ε-CL）， δ-valerolactone（δ-VL） and rac-lactide（rac-LA）. In addition， the heterogeneous PS-U could be easily separated via simple filtration and recycled. It is worth noting that the recycled PS-U catalyst could be reused without significant decrease of catalytic activity.