The original solution of polybutadiene (PBD) rubber from industrial plant was directly used as a starting material to synthesize hydroxyl-terminated polybutadiene (HTPB) with high cis-1

4 content and extremely low glass transition temperature for the first time.The synthetic process was divided into two parts

including the oxidolysis for the preparation of aldehyde group-terminated polybutadiene (ATPB) and the subsequent reduction reaction from ATPB to HTPB by NaBH4.The microstructure of PBD rubber nearly kept unchanged during the whole process so that the resulting HTPB retained a high cis-1

4 content ( 95%).The molecular weight was manipulated in the range of 2200~7000 (determined by 1H-NMR) by controlling the stoichiometric ratio between oxidant (mCPBA) and butadiene units with the polydispersity index within 1.5~2.1

and the functionality (fn) of HTPB was close to 2.0.In comparison with the HTPB prepared by the anionic or free radical polymerization

the HTPB with high cis-1

4 content possesses more regular microstructure (cis-1

4 95%) and extremely low glass transition temperature (Tg -104 ℃).Meanwhile

many high energy-cost and time-consuming processes

such as steam agglomeration and drying in PBD rubber production

and cutting

swelling and dissolving of slab rubber during the preparation of HTPB

can be removed.In short

this process was more economic

efficient and controllable.