Magnetic Biofoams Based on Polyurethane Applied in Oil Spill Cleanup Processes - Natural Polymers, Biopolymers, Biomaterials, and Their Composites, Blends, and IPNs - page 256

table 1. Composition of the biofoams.
Sample Castor Oil

(mL)

Toluene Diisocyanate
(mL)

Water (mL)

PU-1

2.0 2.0 0.25

PU-2 2.0 2.0 0.35

PU-3 2.0 2.0 0.45

PU-4 2.0 1.0 0.25

Figure 4. Biofoams obtained from the compositions shown in Table 1: (a) PU-1, (b) PU-2, (c) PU-3,
(d) PU-4.

Nanoparticles Production
Nanoparticles can be produced from several materials. Among them, iron oxide has
shown great versatility. To obtain magnetic biofoams, it was used maghemite nanopar-
ticles, which is a kind of iron oxide nanoparticles. These nanoparticles were prepared
through the homogeneous precipitation technique. In a typical procedure, the ferric
chloride solution and the deionized water were added into a beaker under continu-
ous agitation. Soon afterwards, the sodium sulfite solution was added to the beaker,
still under continuous stirring. The reaction product was precipitated by the slow