Synthesis, Characterization, Modification And Biodegradation Of Poly(butylene Succinate) (PBS)

In recent years, biodegradable aliphatic polyesters have gained increasingly attention in the development of biodegradable textile products due to its biodegradability. In particular, poly (butylene succinate) (PBS) is extremely popular because of its high melting temperature and favorable thermal properties. However, the product of PBS has poor mechanical properties owing to its high crystallinity. To cater for textile products much better, this paper mainly focused on improvement of mechanical properties for the modified PBS. Poly(ethylene adipate) (PEA) was used to improve the mechanical properties of PBS by mixing. Whereas, poor thermal stability for the PEA with low molecular weight results in poor thermal stability for the mixtures. An effective way to fabricate high molecular weight PEA was also discussed in this paper.The catalyst tetroisopropoxide(TTP), which is commonly used in the synthesis of PBS, was selected to confect with magnesium sulphate(MgSO₄) at molar ratio of 1:1 and 2:1, respectively. The optimum scheme was obtained by comparing the mixture system with single TTP synthesis in the time consumed and mechanical properties of the final products. The TTP/MgSO₄ at the molar ratio of 2:1 works effectively. For the synthesis of PEA, the TTP is superior to p-Toluenesulfonic acid in catalysis.The crystallization behaviors of PBS, PEA and their mixture were studied by DSC. The results showed that PEA reached the maximal crystallization speed at about 16°C.With the increase of PBS content, the mixture at low temperature can hardly crystallized. When PBS mixed with PEA at the ratio of 9:1, the mixture got the minimum crystallinity. Polarizing optical microscope(POM) tests showed the growth rate of PBS and PEA were correlated with temperature.Enzymatic degradation of PBS and PEA was investigated at 37°C in vials containing 3mL potassium phosphate buffer (pH=7.0) in the presence of lipase PS. GPC results showed that as the incubation time went on, the samples reduced (?) steadily, and degradation rate seemed independent of (?). In addition, DSC analysis suggested little increase in T_m andâ–³H values, and this phenomena is more remarkable when it came to PEA.Hydrolytic degradation of PBS and PEA was carried out under 60℃and 90% relative humidity. GPC and DSC were applied to analyze films undergoing degradation. The logarithmic plots of (?) against time for both PBS and PEA tended to be linear, suggesting that all the samples underwent an auto-catalytic random chain scission hydrolysis by their end group.