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The Effect of the Degree of Branching in Hyperbranched Polyesters Used as Reactive Modifiers in Epoxy Thermosets
Author(s) -
Foix David,
Khalyavina Anna,
Morell Mireia,
Voit Brigitte,
Lederer Albena,
Ramis Xavier,
Serra Angels
Publication year - 2012
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201100078
Subject(s) - materials science , thermosetting polymer , epoxy , cationic polymerization , branching (polymer chemistry) , polyester , monomer , curing (chemistry) , bisphenol a , diglycidyl ether , composite material , polymer chemistry , thermal stability , copolymer , polymer , chemical engineering , engineering
The effect of the degree of branching (DB) of a hyperbranched polyester (GBPEX) added as a modifier of new thermosets obtained from diglycidylether of bisphenol A has been studied. The use of ytterbium triflate as cationic initiator allows the hydroxyl chain‐ends in the GBPEX to become covalently linked to the matrix through the monomer activated propagation mechanism. The curing process has been studied by DSC and rheology. The DB of the modifier does not affect appreciably the thermal stability and the chemical reworkability but shrinkage exhibits a significant reduction on increasing the DB. Thermomechanical characteristics are also improved with increasing the DB of the modifier.