Price: 10.00
Introduction
Advanced polymeric materials for coating technology can be obtained both by improving resin
formulations and by better controlling crosslinking and drying processes.
The present tendency to produce tailor-made materials for specific applications makes essential the
prediction of the relationships between molecular structure and properties.
In the frame of UV curable coatings great efforts have been recently done in order to design new
photoinitiators able to improve the curing rate and the ultimate properties of the films in terms of
non yellowing , low odour and adhesion.
In this context polymeric photoinitiators are gaining a great deal of interest (1-3) because they are
expected to offer several advantages as compared with conventional low molecular weight
analogues:
a) Higher photoinitiating activity due to either energy migration along the polymer backbone or
intramolecular hydrogen extraction as well as a—cleavage reactions , that lead to polymer
anchored radical species with improved efficiency
b) Possibility to attach different photosensitive moieties to the same macromolecule in order to
increase curing efficiency
c) No emission of bad odours and reduced yellowing, since most of the fragments from the
splitting reaction remain linked to the polymenc backbone.
The relationships between molecular structure and photoinitiating activity were already investigated
in polymeric systems bearing side-chain benzophenone moieties(4-6), using the microwave
dielectrometry (MD) technique , that permits to evaluate the kinetic parameters of the curing reactions.