Graft copolymers based on a poly(vinyl butyral)(PVB) backbone were
prepared using a non-ionic grafting onto procedure. Monofunctionalised poly( methyl
methacrylate)(PMMA) and poly(phenyl ethyl methacrylate)(PPEMA) were prepared
using a matched free radical initiator and chain transfer system of 4,4 '-azobis-4-cyano
valeric acid (ACV A) and thioglycollic acid (TGA) respectively. By changing the
concentration of TGA, two series of prepolymers having molecular masses from 1400
to 4300 g mor1 were prepared. The carboxylic acid groups at the chain ends of
prepolymers were then converted to the corresponding acid chloride groups. These
were reacted onto the PVB backbone by a condensation reaction with some of the
hydroxyl groups on the PVB. The PVB was chosen so that 21% of the polymer was
vinyl alcohol, 3% was vinyl acetate and the remainder was vinyl butyral. Reaction
conditions were chosen carefully, because PVB was known to aggregate in solution,
and this ensured that grafting frequencies up to 10 grafts per chain were achieved.
The PVB backbone, prepolymers and graft copolymers were all characterised
so that the full architecture of the final graft copolymer was known. GPC was used,
relative to a polystyrene calibration plot, to obtain molecular mass distributions of
polymers. However, PVB and graft copolymers were seen to aggregate and this
resulted in erroneously high molecular mass values. IR spectroscopy was used
qualitatively and quantitatively so that the types of bonds and grafting frequencies
could be obtained. 1H and 13C NMR spectroscopy were used qualitatively and 1H
NMR spectroscopy was used quantitatively so that prepolymer molecular masses and
graft copolymer grafting frequencies could be determined.
Solution viscometry was used to obtain intrinsic viscosities of all polymers in
solution. This showed that the GPC results were correct and that the main method of
separation was due to size exclusion. Slope constants from Huggins and Kraemer
plots suggested that PVB and graft copolymers formed aggregates in solution. Laser
light scattering was used but Zimm plots obtained were markedly curved and this
provides evidence to the existence of aggregates in solution.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.