He Yi’nan,Li Qian,Zhu Caijun,Li Huayi,Zheng Shuirong,Xue Zhaohong,Hu Youliang
Polyethylene based polyurethanes (PE-PUs) with 20% ethyl branches were synthesized through hydrogenation reaction of linear and thermoplastic hydroxyl-terminated polybutadiene based polyurethanes (HTPB-PUs), which has not been explored widely. Linear and thermoplastic HTPB-PUs with M
w
ranged from 130~280 kg/mol were synthesized by microwave-assisted reaction. More importantly, we systematically researched a series of reaction conditions to ensure the degree of hydrogenation meanwhile slow down the extent of degradation reaction of urethane bond. In addition, structure and thermal performance of PE-PUs have been investigated in the present work by NMR, FT-IR, DSC and TGA. The M
w
of PE-PUs ranging from 120~207 kg/mol were carried out with a high temperature GPC. Moreover, the degree of crystalline of PE-PUs with 20% ethyl branches at the range of 10% to 33% were further explored by X-ray diffraction, which in turn certify that the PE-PUs possess certain strength but lower than polyethylene with no branches.
Qingyun Ge,Baihu Dong,Yunqi Chen,Xinqiang Wang,Xiang Wang,Chaogang Fan,Chuhua Chen,Shaohui Lin,Qinmin Pan,Flora T. T. Ng
The polymerization and degradation behaviors of polypropylene carbonate (PPC) of different molecular weights were explored in the presence of catalyst Salen–Co(III)–Cl. The degradation of low-molecular-weight PPC (Mn = 2500 g mol−1, Đ = 1.01) was studied in detail, which was a second-order reaction related to the molar concentrations of PPC and the catalyst. Catalyzed by salen–cobalt, the degradation reaction proceeded spontaneously and could be completed at room temperature and atmospheric pressure, which provided a green and economical method for chemical degradation recycling of CO2-based polycarbonate plastics. On the basis of the degradation investigation, a method for the synthesis of cyclic propylene carbonate from propylene oxide and CO2 at room temperature and atmospheric pressure was developed.
危险品化学品经营许可证（带存储）