The poly（2,2-dimethyltrimethylene carbonate） （PDTC） with one hydroxyl and one formate terminal functions was synthesized by in situ generated, tetrahydrosalen stabilized yttrium borohydride complex. The influences...The poly（2,2-dimethyltrimethylene carbonate） （PDTC） with one hydroxyl and one formate terminal functions was synthesized by in situ generated, tetrahydrosalen stabilized yttrium borohydride complex. The influences of monomer/initiator molar ratio, temperature and reaction time on polymerization of DTC were investigated. Under the condition： [DTC]/[I] = 500, 55℃, toluene： 0.5 mL, DTC： 0.6 g, PDTC with Mn = 15600 and PDI = 2.15 was obtained. Through 1H-NMR and 13C-NMR analyses, the structure of PDTC was characterized and a coordination-insertion mechanism was proposed. In addition, the random copolymerization of DTC and caprolactone （CL） initiated by rare-earth borohydride compound was studied. The microstructure of PDTC-co-PCL includes four diads： DTC-CL, CL-CL, DTC-DTC and CL- DTC, which were determined by the specific signals in lH-NMR spectra. Based on the typical signals of the formate （δ = 8.08） and hydroxyl （δ= 3.34） end groups of PDTC-co-PCL, a mechanism involving DTC monomer inserts before CL during the initiation process was presumed. Furthermore, the thermal properties of amorphous copolymer were characterized by differential scanning calorimetry （DSC）. The results support the random structure of PDTC-co-PCL.展开更多
基金supported by the National Natural Science Foundation(Nos.20674071,20774078)the Special Funds for Major State Basic Research Projects(No.2005CB623802)
文摘The poly（2,2-dimethyltrimethylene carbonate） （PDTC） with one hydroxyl and one formate terminal functions was synthesized by in situ generated, tetrahydrosalen stabilized yttrium borohydride complex. The influences of monomer/initiator molar ratio, temperature and reaction time on polymerization of DTC were investigated. Under the condition： [DTC]/[I] = 500, 55℃, toluene： 0.5 mL, DTC： 0.6 g, PDTC with Mn = 15600 and PDI = 2.15 was obtained. Through 1H-NMR and 13C-NMR analyses, the structure of PDTC was characterized and a coordination-insertion mechanism was proposed. In addition, the random copolymerization of DTC and caprolactone （CL） initiated by rare-earth borohydride compound was studied. The microstructure of PDTC-co-PCL includes four diads： DTC-CL, CL-CL, DTC-DTC and CL- DTC, which were determined by the specific signals in lH-NMR spectra. Based on the typical signals of the formate （δ = 8.08） and hydroxyl （δ= 3.34） end groups of PDTC-co-PCL, a mechanism involving DTC monomer inserts before CL during the initiation process was presumed. Furthermore, the thermal properties of amorphous copolymer were characterized by differential scanning calorimetry （DSC）. The results support the random structure of PDTC-co-PCL.
