Branched polyester based on the polyethylene tere/iso phthalate and trimellitic anhydride as branching agent

Branched polyesters based on the polyethylene terephthalate were synthesized by incorporating isophthalic acid (IPA) and trimellitic anhydride (TMA). TMA has the branching agent role. During the esterification step, only terephthalic acid, IPA, and ethylene glycol were reacted and TMA was added at the beginning of the polycondensation step. Reaction progress was studied using water production and mixing torque increase during esterification and...