Biopolymers - Food and Industrial Bioproducts and Bioprocessing - page 276

monomers in the formation of linear monomers, (co)polymers, cross-linked and
interpenetrating polymers and composite materials for the chemical industry.
Fatty acids and fatty acid methyl esters (FAME) can be used directly or after
functionalization as monomers for the synthesis of a variety of polymeric materials. The
most important functionalization possibilities of the double bonds and the ester groups
have been extensively reviewed in the literature (Biermann et al ., 2001 , 2007 ; Biermann
and Metzger 2004 ).
In the case of ricinoleic acid, which has hydroxyl functionality on the aliphatic chain, it
is easy to introduce functional groups suitable for polymerization leading to fatty acid-based
biodegradable polymers. Domb and Nudelman (1995) utilized succinic and maleic anhydride
(Figure 11.10) to modify ricinoleic acid and subsequently copolymerize the obtained
monomers with sebacic acid to yield a polyanhydride via condensation with acetic anhydride.
These polymers were shown to be useful as drug carriers and they are biocompatible and
degrade within 4-6 weeks both in vivo and in vitro . Ricinoleic acid was also used for
macrolactone formation, but subsequent ring-opening copolymerization with lactide to
produce 100% renewable polyesters was found to be difficult, yielding low molecular
weight polymers and oligomers (Figure 11.10). This behavior was attributed to the low
reactivity of ricinoleic acid macrolactones (Slivniak and Domb, 2005).
In 2008, Sokolsky-Papkov and co-workers prepared copolymers of ricinoleic acid
lactones and lactide then evaluated them as biomaterials for in situ formation of injectable
gels. Copolymerization with lactide resulted in molecular weights in the range of 5-16 kDa
with melting temperatures between 100 and 130 °C for copolymers containing 10-50%
ricinoleic acid.

O OH O OH

O O O O

O O

O

O

Maleic anhydride Succinic anhydride

OH

O

O

Ricinoleic acid methyl ester

Ring closure

O

O

Figure 11.10 Modification possibilities of ricinoleic acid.