The starch plasticized by ionic liquid and glycerol were
submitted to ScCO2 treatment at different temperatures,
pressures and duration of processing time.
X-ray diffraction analysis showed that the structure of
plasticized starch after ScCO2 treatments was close to that
of untreated plasticized starch. The appearance of a V_H
polymorph was induced by both temperature and pressure.
At 120 C, the temperature effect was more predominant in
the evolution of the V_H polymorph than the effect of
pressure.
The plasticizing effects of ScCO2 on plasticized starch
were evaluated by DSC. According to the thermal result,
CO2 acted as a plasticizer and induced mobility and interaction
with the starch chains. In fact, the glass transition
of samples obtained by extrusion process evolved from
7.59 C to 13.21 C for respectively ST-BM-20–100 C-
0 MPa-1 h and ST-BM-20–100 C-10 MPa-1 h samples.
The glass transition of plasticized starch decreased with
the increase of pressure and with the decrease of temperature.
These results also show an increased interaction
between CO2 and plasticized starch with ionic liquid compared
to glycerol–starch samples. The use of carbon dioxide
can therefore reduce the quantity of plasticizers and
enhance properties.
Ackn