; ;Qiting Lu
. 2013, 44(17): 23-0.
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The trimellitic anhydride – ethanediol polyester (TEPES) and the trimellitic anhydride – 1,3-butanediol polyester (TBPES) have been synthesized with trimellitic anhydride (TMA), ethanediol (EG) or 1,3-butanediol (1,3-BG) as raw materials, and monobutyl tin oxide as the catalyst. The results show that, the hydroxyl value, number average functionality (fn) and weight average functionality (fw) of TEPES are 400.0 mg KOH/g, 6.55 and 7.31, respectively. The hydroxyl value, fn and fw of TEPES are 357.2 mg KOH/g, 5.87 and 6.49, respectively. It can be seen that TEPES has a wider molecular weight distribution than TBPES. 1H NMR spectra and TGA curves reveal that, during the reaction there are not only a single hydroxyl reaction, but also a dihydroxy crosslinking reaction between dihydroxy alcohol and TMA, which further verify the GPC results. In addition, The synthesized polyester polyols both have a few raw dihydroxy alcohol, which is also identified by TGA。It is indicated that TBPES has a better low temperature thermal stability than TEPES, while its high temperature thermal stability is worse than TEPES. With the same apparent density 60 kg?m-3, the PU rigid foams of different polyol synergistic systems, have been prepared with GR-835G, TEPES, TBPES and PM-200, as main raw materials. Comparing to the single system with GR-835G, the compressive modulus of the polyol synergistic system between TEPES and GR-835G, has a greater improvement than that of the polyol synergistic system between TBPES and GR-835G. The compressive strength of PU rigid foams will decrease with TEPES used, however, The compressive properties can be improved using TBPES.