Abstract (Invited) |
High Power Ultrasound in Making and
Breaking Polymers
G.Price (University of Bath, Bath, UK)
e-mail:
g.j.price@bath.ac.uk
The
passage of high power ultrasound through liquids can cause cavitation resulting
in the generation of reactive intermediates such as free radicals as well as
producing high shear conditions around the collapsing bubble. In heterogeneous
systems, efficient mixing and enhanced transport of reagents to and from
surfaces can occur. All of these effects can be exploited in polymer chemistry.
The oldest known effect is the breakage of long polymer chains in solution when
exposed to ultrasound. Recent work in understanding the kinetics of the process
and its usefulness in promoting polymer mixing will be described. The
usefulness of ultrasound in preparative work will be illustrated by reference
to investigation of radical polymerisation using sonoluminescence and
spectroscopic measurements, with other applications selected from the
preparation of silicon containing polymers by reactions at metal surfaces,
emulsion polymerisation processes and the modification of polymer surfaces. The
emphasis will be to illustrate how the use of ultrasound allows us to control
and/or modify the reactions.
Section
: 11