Hyperbranched polymers were modified with terminal methacryloyl groups to be used as crosslinkers. The photoinitiated polymerization of several methacrylic monomers was examined in the presence of the hyperbranchedmacromers and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819®) as a photoinitiator, upon UV irradiation. The photopolymerization kinetics was systematically studied by fluorescence and photoDSC in real time and in situ. Six types of monofunctional methacrylic monomers, two types of difunctional methacrylic monomers and four types of (meth)acrylate-modified hyperbranchedmacromers with different structures were employed for series of photopolymerization reactions. The incorporation of the hyperbranchedmacromers allows to increase the conversion at gelation and thus, final conversion. This behaviour is dependent on monomer and macromer nature and has been explained as due to an increase of the free volume fraction and confirmed by fluorescence. The results indicate that H-bonding and π-stacking induce self-assembly of hyperbranchedmacromers leading to reaction induced phase separation at the highest concentration of hyperbranched macromer used

The authors would like to thank the Plan Nacional I+D+I (Ministerio de Ciencia e Innovación) for financial support (MAT2006-05979) as well as the Comunidad Autónoma de Madrid for the funding through I +D Program (S0505/MAT- 0227)

Peer reviewed