Premium
New Thermosets Obtained by Thermal and UV‐Induced Cationic Copolymerization of DGEBA with 4‐Phenyl‐ γ ‐butyrolactone
Author(s) -
FernándezFrancos Xavier,
Salla Josep M.,
Pérez Guillermo,
Mantecón Ana,
Serra Àngels,
Ramis Xavier
Publication year - 2009
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200900118
Subject(s) - copolymer , cationic polymerization , polymer chemistry , glass transition , thermal stability , curing (chemistry) , thermosetting polymer , trifluoromethanesulfonate , polymerization , materials science , ether , ring opening polymerization , chemistry , polymer , organic chemistry , composite material , catalysis
Abstract Mixtures of DGEBA with 4‐phenyl‐ γ ‐butyrolactone (PhBL) were cationically copolymerized in the presence of ytterbium triflate or triarylsulfonium hexafluoroantimoniate as thermal or photo initiator respectively. Changes during curing and final properties of the cured materials were studied by means of DSC, FT‐IR/ATR, TMA, DMTA, TGA and densitometric measurements. The formation of a network containing polyether and poly(ether‐ester) moieties was demonstrated to take place through the ring‐opening polymerization of a spiroorthoester intermediate (SOE) formed during the copolymerization. An increase in the proportion of lactone resulted in an increase in the curing rate, a decrease in the shrinkage after gelation and in the thermal stability and glass transition temperature ( T g ). A strong influence of the initiator on the curing mechanism was observed. As a consequence, the photocured materials exhibited superior thermal stability and T g than those obtained thermally.