P. Ghosh et G. Pal, PHOTOPOLYMERIZATION OF METHYL-METHACRYLATE USING MORPHOLINE-BROMINE CHARGE-TRANSFER COMPLEX AS THE PHOTOINITIATOR, European Polymer Journal, 34(5-6), 1998, pp. 677-682
Photopolymerization of methyl methacrylate (MMA) was kinetically studi
ed using near UV/ visible light at 40 degrees C and by employing the m
orpholine (MOR)-bromine (Br-2) charge transfer (CT) complex as the pho
toinitiator. The rate of polymerization (R-p) was dependent on the mor
pholine:bromine mole ratio; the 1:2 (MOR-Br-2) CT complex acted as the
latent initiator complex C which underwent further complexation with
monomer molecules to give the actual initiator complex, I. Using a 1:2
(MOR-Br-2) CT complex as the latent initiator, the initiator exponent
for bulk photopolymerization of MMA was 0.08 and the monomer exponent
determined from studies of photopolymerization in a carbon tetrachlor
ide diluted system was 1.20. Benzoquinone behaved as a strong inhibito
r and the polymers tested positive for the incorporation of bromine at
oms as end groups. Polymerization followed a radical mechanism. Kineti
c non-ideality was revealed by low (<<0.5) initiator exponent and a mo
nomer exponent of greater than unity; it was explained in terms of pri
mary radical termination. (C) 1998 Elsevier Science Ltd. All rights re
served.