Abstract: Hyperbranched polyester (HBPE) was synthesized via condensation polymerization of triethylolpropane and 2,2is(hydroxymethyl) propionic acid, which was used to modify phenolic resins(PF). The structure and thermal property of the blend were characterized with FTIR and differential scanning calorimetry (DSC), a relation between the effective activation energy and the fractional conversion during the curing was determined using a modelfree isoconversional method, viz, FlynnWallOzawa (FWO) method. Due to intermolecular hydrogen bonding between hydroxyl groups of HBPE and PF, a single glass transition was observed. The impact and bend strengths of PF were increased with the addition of HBPE, reached 4.5 kJ/m2 and 77.84 MPa, respectively.

Key words: hyperbrached polyester, phenolic resins, modify, curing kinetics