Synthesis, characterization, and properties of long‐chain branched poly(butylene succinate)

Abstract

AbstractLong‐chain branched poly(butylene succinate) were synthesized through a two‐step process of esterification and polycondensation, using 1,2,4‐butanetriol (1,2,4‐BT) as a long‐chain branching agent. The effect of long‐chain branches on the crystallization behaviors, rheological properties, and tensile properties was investigated systematically. The results of differential scanning calorimetry and polarized optical microscopy showed that with the increasing of 1,2,4‐BT segments, the crystallization temperatures and glass transition temperatures increase slightly, while the relative crystallinity degree decreases gradually. Also, the double‐banded extinction patterns with periodic distance along the radial direction were observed in the spherulites of long‐chain branched poly(butylene succinate), similar to that of linear poly(butylene succinate) (PBS). The result of wide‐angle X‐ray diffraction indicated that the incorporation of 1,2,4‐BT segments had little effect on the crystal structure of PBS. However, based on data from rheology and tensile testing, the viscoelastic properties of long‐chain branched PBS under shear flow were different from the linear PBS. For example, the complex viscosities, storage modulus, and loss modulus of long‐chain branched PBS at low frequency were significantly enhanced in comparison with those of linear PBS. In addition, long‐chain branched PBS showed higher tensile strength than that of linear PBS without notable decrease in the elongation at break when compared with linear PBS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012