In polymer chemistry, the term prepolymer or pre-polymer, refers to a monomer or system of monomers that have been reacted to an intermediate-molecular mass state. This material is capable of further polymerization by reactive groups to a fully cured, high-molecular-mass state. As such, mixtures of reactive with un-reacted monomers may also be referred to as pre-polymers. The term "pre-polymer" and "polymer precursor" may be interchanged.
Polyurethane and polyurea prepolymers
In
polyurethane chemistry, prepolymers and oligomers are frequently produced and then further formulated into CASE applications -
,
,
, and
. An
isocyanate (usually a diisocyanate) is reacted with a
polyol. All types of polyol may in theory be used to produce polyurethane prepolymers.
[Howarth G.A "Synthesis of a legislation compliant corrosion protection coating system based on urethane, oxazolidine and waterborne epoxy technology" page 40 Master of Science Thesis April 1997 Imperial College London] These then find use in CASE applications. When polyurethane dispersions are synthesized, a prepolymer is first produced usually modified with DMPA. In polyurea prepolymer production, instead of a polyol a poly
amine is used.
Lactic acid as a polymer precursor
Two
of
lactic acid can be dehydrated to the cyclic molecule
lactide, a
lactone. A variety of
can polymerise lactide to either
heterotactic or
syndiotactic polylactide, which as biodegradable polyesters with valuable (inter alia) medical properties are currently attracting much attention.
Nowadays, lactic acid is used as a monomer for producing polylactic acid (PLA) which later has application as biodegradable plastic.
See also
