Cleavable polybutadiene rubber: A versatile precursor to hydroxyl-terminated or multi-hydroxyl polybutadiene and polyethylene. (19th December 2016) - Zhou, Qinzhuo
Abstract: A series of hydroxyl functionalized polybutadienes has been prepared by combining the oxidolysis and reduction of cis -polybutadiene rubber (BR). For the first time, multi-hydroxyl polybutadiene (MHPB) with α, ω- and intrachain hydroxyl groups was synthesized through the simultaneous reduction of –CHO and epoxy groups in epoxidized aldehyde group terminated polybutadiene (EATPB) by sodium dihydro-bis-(2-methoxyethoxy) aluminate (Red-Al). The corresponding hydroxyl functionalized polyethylenes, including hydroxyl-terminated polyethylene (HTPE), multi-hydroxyl polyethylene (MHPE) and hydroxyl-terminated polyethylene with ethyl branches (FHTPE), were readily obtained via the hydrogenation of C=C double bonds in the functionalized polybutadienes with TSH/TPA regents. The microstructures of all the products were confirmed by 1 H NMR, 13 C NMR and FT-IR, and their thermal properties were determined by TGA and DSC. It has been indicated that the linear HTPE and MHPE possessed high initial thermal degradation temperature, high degree of crystallinity, and high melting temperature due to their stereoregular microstructure. However, the FHTPE obtained through the hydrogenation of HTPB from free radical polymerization had much lower degree of crystallinity and melting temperature due to the presence of more ethyl branches. Graphical abstract: Highlights: MHPB with α, ω- and controllable intrachain hydroxyl groups was synthesized. Hydroxyl functionalized polyethylenes (HTPE, FHTPE and MHPE) were synthesized. Linear HTPE has high degree of crystallinity (70%) and melting temperature (123.2 °C). MHPE has lower degree of crystallinity (47%) and melting temperature (110.9 °C).