3. Results and discussion
3.1. The preparation of PBT
PBT with different molecular weights were synthesized via the one-step strategy of direct polycondensation from BD and l-TA,using PTSA as a catalyst. When compared with traditional pro-cedure of tedious protection and deprotection of the pendanthydroxyl groups [13], the reaction process was simple and feasible.The synthesis data are shown in Table 1.