Synthesis and characterization of segmented poly(butylene succinate) urethane ionenes containing secondary amine cation

The segmented poly(butylene succinate) urethane ionenes (PBSUI) containing secondary amine cation were synthesized by chain extension reaction of dihydroxyl terminated poly(butylene succinate) and diethanolamine hydrochloride (DEAH) in the presence of hexamethylene diisocyanate. NMR, DSC, WAXD, POM, SAXS, DMA, and rotational rheometer were used to characterize the structure and properties of the PBSUI, and the tensile properties and hydrolytic degradation of the PBSUI were also investigated. All the results suggest that the content of urethane ionic group plays an important role in tuning the properties of the PBSUls. The crystallization rate increased first and then decreased and the equilibrium melting temperature increased gradually with increasing urethane ionic group content. The maximum crystallization rate was obtained for PBSUI with 3 wt% DEAH. The obvious clusters formed by aggregation of urethane ionic group were evidenced by DMA and SAXS for the PBSUI containing 5 wt% DEAH. The complex viscosity increased significantly with increasing urethane ionic group content due to the physical crosslinking effect resulted from aggregation of ionic groups. The storage modulus increased with DEAH content increased up to 3 wt %, while decreased with further increasing DEAH content. Tensile testing indicated incorporation of urethane ionic group did not change the tensile properties apparently. The hydrolytic degradation rate of the samples increased with the increase in urethane ionic group content which was mainly ascribed to the increased hydrophilicity. (C) 2014 Elsevier Ltd. All rights reserved.