Effects Of Catalysis On Synthesis Of Poly (Butylene Succinate)

Biodegradable poly(butylenes succinate) (PBS) was prepared by direct esterification and polycondensation route using tetrabutoxytitanium as catalyst. The effects of monomer feed molar ratio, polycondensation temperature and catalyst concentration on molecular weight, acid value and so on were investigated in detail to determine the suitable reaction conditions. Then, six Ti-based compounds with different structure were used as catalysts to synthesize PBS to get insight into the relationships between structure and activity of Ti-based catalysts for PBS synthesis.. Further, a primary catalyst together with different cocatalysts were used to systhesize PBS, catalytic activity of cocatalysts and the effect on properties of products were studied.The results showed that the optimal synthetic conditions was:monomer feed molar ratio BD/SA 1.3; catalyst concentration 300ppm and catalyst added after esterrification; polycondensation temperature 230℃; the pressure below 50Pa; polycondensation time 2.5h. Under these conditions, PBS with Mn of 7.8 X 104 could be synthesized. The thermal analysis indicated that catalytic activity of different Ti-based compounds was related with its steric hinderance. When Bi2O3 was added into TAIP catalyst as cocatalyst, Mn of the PBS reached to 1×105, which suggested that Bi2O3 was optimal cocatalyst.