| A series of poly (butylene succinate) PBS, poly (butylene succinate-co-1,2-propylene succinate) PBSP, poly (butylene succinate-co-1,2-pentylene succinate) PBST and poly (butylene succinate-co-1,2-hexylene succinate) PBSH were synthesized by direct esterification and polycondensation route with succinic acid,1,4-butanediol, respectively with1,2-propanediol,1,2-pentanediol and1,2-hexanediol. The PBS and its copolyesters were characterized with Ubbelohde viscometer,1H-NMR, DSC, TGA, POM, mechanics performance testing and rheological testing. Then, the influece of branched chain segment content and branched chain length on the PBS copolyesters’molecular weight, thermal properties, crystallization behavior, mechanical properties and rheological behavior were studied.Results showed that,(1) the PBS and its copolyesters are random copolymers, the number average molecular weight were4.15×104～5.20×104, the addition of modified monomers had almost no effect on the molecular weight of PBS copolyesters.(2) While with the increase of the content or length of branched chain, the PBS copolyesters still showed good thermal properties;(3) the crystalline form of PBS and its copolyesters was banded spherulites and the nucleation mode was heterogeneous nucleation; With the higher crystallization temperature, the crystallization rate of the copolyesters became more slowly. While at the same isothermal crystallization temperature, with the increase of branched chain segment content or length of the copolyesters, the corresponding crystalline rate became more slowly. The change of mechanical properties of the copolyesters was coincide with the crystallization behavior.(4) PBS and its copolyesters were performed as a typical pseudoplastic fluid. The change of the molecular structure of PBS copolyester had complicated influence on the rheological properties. Compared with the linear PBS, branched PBS showed higher zero-shear viscosity value, better elastic effect and strain hardening performance. |
PDF Full Text Request