Synthesis Of Double End-Functionalized Liquid Polybutadiene Rubber And Research Of UV Curing

3D printing technology, which belongs to manufacturing industry of new functional materials, is presently recognized as an important standard for measurement of the level of science. As we all know, material plays a decisive role in forming structure, it would largely limit the applications of 3D printing. Recently, extensive efforts have been taken to prepare origin material for 3D printing, aiming to improve print speed with more cost efficient and higher level of precision.Our research focus is liquid rubber which has fluidity at room temperature, their molecular weight usually under 1000. One of the major advantages of liquid rubber compared to other materials is the feature of solvent-free, it means that liquid rubber can be operated easily without any pollution to the surroundings. In addition, liquid rubber had been referred as future rubber, having a broad prospects for development. In this paper, polybutadiene liquid rubber with dual-functional was synthesized by living anionic polymerization. Due to the carbon-carbon structure in molecular chain, it would take place curing reaction under UV light.In this polymerization system, cyclohexane was used as solvent, homemade dilithium was used as initiator, polybutadiene with low molecular weight and narrow polydispersity was finally synthesized.Then excess ethylene oxide was added to react with ends of polymer chain, obtaining hydroxyl terminated polybutadiene. After that, acryloyl chloride was also introduced, it formed double bond structure at the end of chain. Characterization of synthesized polymer was determined by NMR> IR^ GPC. It shown that molecular weights were among 4000-10000, the narrowest polydispersity was 1.16, and the content of 1, 2-polybutadiene structure were 60%. The efficiency of capping reaction with ethylene oxide was nearly 80%, as for acryloyl chloride, the rate was over 90%.As the liquid rubber composed by double-ended functionalized polybutadiene, it can be used as 3D printing material by UV curing reaction. Experiments confirmed that solid products with elastic characteristic could be synthesized by adjusting system composition and controlling the position of light triggers. Specific methods of the experiment are as follows. One synthetic route is using dual thiol to occur click reaction for UV-curing. It was found that conversion rate of double bond can approach 90% after 60s light exposure and completely reacted at last. The second method is using radical photopolymerization system, it needs acrylate as reactive diluent and photoinitiator. The conclusion was similar to above, and curing reaction could be controlled by using different initiators.