Chemistry Reference
In-Depth Information
ABSTRACT
The data on aromatic polyesters based on phthalic and
n
-oxybenzoic acid
derivatives have been presented and various methods of synthesis of such
polyesters developed by scientists from different countries for last 50
years have been reviewed.
7.1 INTRODUCTION
The important trend of modern chemistry and technology of polymeric
materials is the search for the possibilities of producing materials with
novel properties based on given combination of known polymers.
One of the most interesting ways in this direction is the creation of
block-copolymers macromolecules of which are the “hybrids” of units dif-
fering in chemical structure and composition. Thermodynamical incom-
patibility of blocks results in stable microphase layering in the majority
cases what, finally, allows one to combine the properties of various frag-
ments of macromolecules of block-copolymers in an original way.
Depending on diversity of chemical nature of blocks, their length,
number and sequence as well as their ability to crystallize one can ob-
tain materials of structure and properties distinguishing from that of initial
components. Here are the huge potential possibilities the practical realiza-
tion of which has already been started. The most evident is the creation
of thermoplastic elastomers (TPEs) - high-tonnage polymeric materials
synthesized on the base of principle of block-copolymerization: joining
of properties of both thermoplastics and elastomers in one material. The
great potentials of block-copolymers caused considerable attention to
them within the last years.
Nowadays, all the main problems of physics and physic-chemistry of
polymers became closely intertwined when studying block-copolymers:
the nature of ordering in polymers, the features of phase separation in
polymers and the influence of general molecular parameters on it, the sta-
bility of phases at exposing to temperature and power impacts, the features
of physical and mechanical properties of microphases and the role of their
conjugation.
Existing today numerous methods of synthesis of block-copolymers
give the possibility to combine unlimited number of various macromol-
ecules, what already allowed people to synthesize multiple block-copo-
