Chemistry Reference
In-Depth Information
O
C
O
O
O
O
C
O
O
O
C
O
O
O
Figure 3.2 The structure of epoxidized soybean oil (ESO).
O
O
12
9
O
O
O
12
9
O
O
O
12
9
O
Figure 3.3 The structure of euphorbia oil (EuO).
natural epoxy oil from Euphorbia resinifera seeds, and its structure is shown
in Figure 3.3. The advantage of polymerization of EuO is that the epoxidation
reaction of plant oils is avoided. The polymerization of EuO has been re-
ported by Liu and co-workers.
10
Liquid carbon dioxide was first used as a solvent for polymerization in
1960,
11
but it is only recently that there has been an explosion of interest in
the use of supercritical carbon dioxide (scCO
2
). This is due to its low toxicity
of CO
2
and the lack of solvent residues in the final product, as well as it
being an environmentally acceptable alternative to conventional solv-
ents.
12-14
Also, CO
2
is inexpensive, readily available and non-flammable.
Supercritical CO
2
is a green medium for organic reactions and polymeriza-
tions. The critical parameters of CO
2
are a P
c
(critical pressure) of 73.8 bar
and a T
c
(critical temperature) of 31.1 1C. Although the T
c
is low, obtaining
the high P
c
may not be easy. However, CO
2
in the liquid state provides many
of the advantages of the supercritical system, but at a lower pressure and
temperature. We wish to review here the work we carried out on the poly-
merization of plant oils such as SBO, ESO and EuO using supercritical and
subcritical CO
2
as reaction media. The catalyst used for the polymerization
was a Lewis acid, boron trifluoride diethyl etherate, BF
3
OEt
2
. The formed
polymers are referred to ''PSBO'', ''RPESO'' and ''RPEuO'' for SBO, ESO and
EuO, respectively. The thermal properties of the resulting polymers have
been determined. Also, the conversion of RPESO into polysoap (HPESO) and
its surface and interface properties have been studied in order to explore
their applications in various areas. Here, P means polymerized, RP means
ring-opening polymerized, H means hydrolyzed.
