"Front Matter". In: Modern Polyesters: Chemistry and Technology of ...

Preface
Polyesters are one of the most important classes of polymers in use today. In
their simplest form, polyesters are produced by the polycondensation reaction of
a glycol (or dialcohol) with a difunctional carboxylic acid (or diacid). Hundreds
of polyesters exist due to the myriad of combinations of dialcohols and diacids,
although only about a dozen are of commercial significance.
Mankind has been using natural polyesters since ancient times. There are
reports of the use of shellac (a natural polyester secreted by the lac insect)
by the ancient Egyptians for embalming mummies. Early last century, shellac
was still used as a moulding resin for phonographic records. True synthesis of
aliphatic polyesters began in the 1930s by Carothers at DuPont in the USA and
more significantly with the discovery of aromatic polyesters by Whinfield and
Dickson at the Calico Printers Association in the UK. The complete historical
development of polyesters is described in Chapter 1.
Polyesters are in widespread use in our modern life, ranging from bottles
for carbonated soft drinks and water, to fibres for shirts and other apparel.
Polyester also forms the base for photographic film and recording tape. Household
tradenames, such as Dacron ® ,Fortrel ® , Terylene ® and Mylar ® , demonstrate
the ubiquitous nature of polyesters.
The workhorse polyester is poly(ethylene terephthalate) (PET) which is used
for packaging, stretch-blown bottles and for the production of fibre for textile
products. The mechanism, catalysis and kinetics of PET polymerization are
described in Chapter 2. Newer polymerization techniques involving the ringopening
of cyclic polyester oligomers is providing another route to the production
of commercial thermoplastic polyesters (see Chapter 3).
High-molecular-weight polyesters cannot be made by polymerization in the
molten state alone – instead, post-polymerization (or polycondensation) is performed
in the solid state as chips (usually under vacuum or inert gas) at temperatures
somewhat less than the melting point. The solid-state polycondensation of
polyesters is covered in detail in Chapters 4 and 5.