Facile synthesis of PET-based poly(ether ester)s with striking physical and mechanical properties

Abstract

New poly(ethylene terephthalate) (PET)-based poly(ether-ester)s were successfully synthesized, by using the bicomponent catalyst of titanium isopropoxide (TPT) and methanesulfonic acid (MSA) to directly catalyze polycondensation of terephthalic acid and ethylene glycol, for randomly copolymerizing poly(ethylene terephthalate) (PET), poly(diethylene terephthalate) (PDET) and poly(ethylene oxide terephthalate) (PEOT), which denoted as linear PET-co-PDET-co-PEOT. The chemical structures of PET-co-PDET-co-PEOT were evidenced by two-dimensional and one-dimensional nuclear magnetic resonance (2D and 1D-NMR) techniques, and the segment contents of the poly(ether-ester) were tunable by adjusting the feeding molar ratios of catalytic systems. The thermal properties, mechanical properties and rheological behavior of linear PET-co-PDET-co-PEOTs were studied in detail. In particular, the branched PET-co-PDET-co-PEOT were afforded via introducing the multifunctional reagents, such as 1,1,1-tris(hydroxymethyl) ethane (TME), 2,2-dimethylolpropionic acid (DMPA) or 1,2,3-propanetricarboxylic acid (PTA). Compared to linear PET-co-PDET-co-PEOTs, the elongation at break of the branched PET-co-PDET-co-PEOTs were strongly enhanced to 409%, and their flow properties were accordingly altered, as revealed by rheological analysis. The novel PET-based poly(ether-ester)s will be promising as potential thermal elastomers.