3.3. Effect of MP on the isothermal crystallization mechanism of palm oil
Fig. 5 shows the DSC crystallization curves recorded during
cooling of PO and PO blended with MP in different concentrations
(1, 2, 4 and 8%). A higher concentration of MP yielded an earlier crystallization
along with the appearance of extra crystallization peaks at
higher temperatures for the highest concentrations. The occurrence
of extra peaks was also clear from the stop-and-return melting curves
recorded during the early stages of isothermal crystallization. The
results obtained at 15 °C for the blend with the highest MP concentration
(8%) is shown in Fig. 6D. As can be seen, the 8% MP blend showed
three melting peaks after 5 min crystallization at 15 °C. The first
melting peak showed a peak maximum at 27 °C, the second peak at
38 °C and the last melting peak at 52 °C. During the 90 min isothermal
time, a polymorphic transition seemed to occur as the first melting
peak disappeared while another peak with a peak maximum at
31 °C appeared. The emerging peak partly overlapped with the second
melting peak which stayed present as a shoulder. At the end of
the isothermal period, three fractions thus seemed to be present: a
high-melting fraction and two fractions with only a small difference
in melting point
3.3. Effect of MP on the isothermal crystallization mechanism of palm oilFig. 5 shows the DSC crystallization curves recorded duringcooling of PO and PO blended with MP in different concentrations(1, 2, 4 and 8%). A higher concentration of MP yielded an earlier crystallizationalong with the appearance of extra crystallization peaks athigher temperatures for the highest concentrations. The occurrenceof extra peaks was also clear from the stop-and-return melting curvesrecorded during the early stages of isothermal crystallization. Theresults obtained at 15 °C for the blend with the highest MP concentration(8%) is shown in Fig. 6D. As can be seen, the 8% MP blend showedthree melting peaks after 5 min crystallization at 15 °C. The firstmelting peak showed a peak maximum at 27 °C, the second peak at38 °C and the last melting peak at 52 °C. During the 90 min isothermaltime, a polymorphic transition seemed to occur as the first meltingpeak disappeared while another peak with a peak maximum at31 °C appeared. The emerging peak partly overlapped with the secondmelting peak which stayed present as a shoulder. At the end ofthe isothermal period, three fractions thus seemed to be present: ahigh-melting fraction and two fractions with only a small differencein melting point
การแปล กรุณารอสักครู่..