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Five secondary amine terminated poly（ester-amine）s（defined as PEA）with controlled molecular structures were synthesized through reacting excessive piperazine with phthalicdiglycol diacrylate（PDDA）and 1

1

1-trimethylolpropane triacrylate（TMPTA）at a constant secondary amine/acrylate group ratio of 1.5/1 and at different PDDA/TMPTA molar ratios. Both IR and

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H-NMR spectra indicated that all acrylate groups were consumed in the reaction

based on which the structural parameters were calculated from the

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H-NMR spectra.With decreasing PDDA/TMPTA ratio

the content of secondary amine

degree of branching

molecular weight

T

g

and T

d

increased accordingly.These polymers were further used as both crosslinkers and flexibilizers for a linear epoxy resin E51 to form cured films under ambient condition.The gel content

relative hardness and T

g

of the resulting films increased as PEA molecules changed from linear to highly branching structures.Due to the flexibility of PEA molecules

all the films possessed excellent mechanical performance.