12th
Bratislava IUPAC/EPF International Conference on Polymers:
Modified Polyolefins for Advanced Polymeric Materials
Symposium
Editor, E. Borsig
Editor-in-Chief, Hartwig Hocker
Editors,
W. Guth, B. Jung, I. Meisel, and S. Spiegel
Wiley-VCH (1998), pp.
1-172
ISBN 3-85739-326-2.
Preface
The
12th Bratislava IUPAC/EPF International Conference on Polymers devoted
to modified polyolefins for advanced polymeric materials was held in
Bratislava from August 25 to August 28, 1997.
The
aim of the Conference was to bring together scientists from academical
and industrial institutions to stimulate the exchange of ideas on recent
advances in chemistry and physics of modified polyolefins leading to
advanced polymeric materials.
More
than 120 scientists coming from 23 countries of the five continents
presented 10 invited lectures, 22 contributed papers and 5 1 posters.
At the opening ceremony of the Conference, the
Slovak Chemical Society decided to grant Honorary Memberships to Professors
Rolf C. Schulz from the University of Mainz and Piet J. Lemstra from
the University of Technology, Eindhoven as an expression of our deep
appreciation of their scientific merits, support, and friendly approach
to the Slovak macromolecular community.
The
Conference showed that there are still two main kinds of effective chemical
modification of polyolefins: the catalytic systems in polyolefin production
and during polyolefin processing using extruders as reaction vessels.
New catalysts tolerating known catalyst poisons such as carbon monoxide
in the copolymerization with ethylene or methyl methacrylate and other
vinyl-functional esters can be incorporated into polyethylene. They
allow to control molar mass, end groups, stereochemistry, monomer incorporation,
and morphology. In addition to isotactic poly(propylene) also syndiotactic,
hemiisotactic poly(propylene)s are available in high yields. Polyethylene
short and long-chain-branching is controlled either by uniform ethylene
copolymerization with I -olefins using "single-site " metallocene catalysts
or by migratory polyinsertion of ethylene, respectively.
An
alternative variation of the polyolefin structure by catalysts is the
preparation of elastomeric poly(propylene) the properties of which are
influenced by variation of the length of isotactic and atactic segments.
The incompatibility of polyolefins with other,
mainly polar polymers requires to adjust their apolar chains to more
polar blend components using peroxide-initiated grafting of acrylic
and maleic anhydride derivatives onto polyolefin chains. Many Conference
contributions were also devoted to other kinds of functionalization
of polyolefins, mainly poly(propylene), which could extend the possibilities
of the preparation of entirely new materials, including polymer blends.
New
effective methods of grafting of vinyl monomers onto polyolefins, mainly
on poly(propylene) were also reported. The grafting of styrene onto
poly(propylene) with more than 50% yield in the solid state seems to
be very advantageous.
The
results obtained in the preparation of polyolefin blends showed that
reactively compounded polymer blends have generally better mechanical
properties than the blend prepared only by mechanical mixing, It was
illustrated in PP rubber blends and also during UHMW-PE spinning with
reactive solvents. The presented contributions on interaction between
polymer components in polyolefin blends like dispersion forces, the
influence of the crystalline part on the miscibility and morphology
of the
blend, and adhesive properties of modified polyolefins onto metal have
a practical importance for the development of the new advanced polyolefin
materials.
These few examples of the topics discussed at the Conference demonstrate
that the participants brought fresh ideas into the field of modification
of polyolefins.
My special thanks go to those who have provided their manuscripts for
publication in this volume of
Macromolecular Symposia.
Bratislava,
November
1997
Eberhard Borsig
Symposium Editor
