Preparation of CO2-based poly(carbonate-co-lactide) with different porphyrin aluminum (III) catalysts

Two-component catalysts composed of tetra ( para -X substituted) phenylporphyrin aluminum (III) chloride, T ( p -X-P)PAlCl, (where X = H, F, Cl, Br, CH 3 , OCH 3 , tert -butyl), and cocatalyst bis(triphenylphosphine)imminium chloride (PPN + Cl − ), could initiate the polymerization of propylene oxide (PO). And they could react with rac -lactide, ( rac -LA), in the presence of propylene oxide (PO), to yield chains of enriched isotactic polylactide (PLA) with trace polyether segment. Also, these catalysts displayed different catalytic activity in the copolymerization of CO 2 and PO, resulting in poly(carbonate-co-ether) copolymer with different carbonate unit content (CU%). Further, these catalysts could initiate one-pot regio- and stereo- selective terpolymerization of rac -LA, CO 2 and rac -PO, resulting in multi-blocky poly(carbonate-co-lactide) with trace polyether segment. The structure of the products was verified by 1 H NMR, 13 C NMR, GPC, and DSC analysis, and it was found that variation of substitution groups in the periphery of porphyrin ligand would affect on the catalytic efficiency of ter-polymerization, and the relative polymerization reaction ratio of the ring-opening polymerization of LA (ROP) to the ring-opening copolymerization of PO and CO 2 (ROCOP), resulting in ter-polymer with different contents of PLA segment and PPC segment. However, H-T % in polycarbonate unit and P i % in polylactide unit did not vary much with the change of catalysts. Graphical