Influence of Polydimethylsiloxane on the Oxygen Concentration of Oils at Various Temperatures
Influence of Polydimethylsiloxane on the Oxygen Concentration of Oils at Various Temperatures
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DOI：
10.1007/s11746-011-1762-7
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发表时间：
2011-07-01
影响因子：
2
通讯作者：
White, Pamela J.
中科院分区：
文献类型：
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作者：
Gerde, Jose A.;Hammond, Earl G.;White, Pamela J.
在未添加聚二甲基硅氧烷 (PDMS) 的大豆油和橄榄油中测试了温度对油中氧浓度的影响，结果表明，氧浓度随着温度的升高而增加，达到约 100 A 摄氏度。超过 100 A 摄氏度时，氧浓度突然下降。这种变化归因于油氧化的氧气吸收率和消耗率之间的平衡，在温度高于 100°C 时，这有利于氧气消耗而不是吸收。在 93 至 180°C；因此表明PDMS具有氧屏障作用。通过比较油的内部温度和表观表面温度，确定了保持在 180 A 摄氏度的大豆油中空气-油界面上 PDMS 的积累情况。当油保持在恒定的内部温度时，表观表面温度的降低归因于PDMS在空气-油界面中的积累导致表面发射率的变化。证实空气-油界面上存在 100 ppm 的 PDMS，该浓度大于在油表面形成单层 PDMS 所需的浓度。
The effect of temperature on the oil oxygen concentration, tested in both soybean and olive oils with no added polydimethylsiloxane (PDMS), showed that the oxygen concentration increased with temperature to approximately 100 A degrees C. Above 100 A degrees C, the oxygen concentration abruptly decreased. This change was attributed to the balance between the rates of oxygen uptake and consumption by oil oxidation, which favored oxygen consumption over uptake at temperatures above 100 A degrees C. The addition of 100 ppb PDMS to soybean oil, enough to form a continuous layer over the surface of the oil, reduced the oxygen concentration when compared to a soybean oil control containing no added PDMS at temperatures ranging from 93 to 180 A degrees C; thus suggesting an oxygen barrier effect of PDMS. The accumulation of PDMS at the air-oil interface in soybean oil held at 180 A degrees C was determined by comparing the oil's internal temperature and the apparent surface temperature. A decrease in the apparent surface temperature while the oil was held at a constant internal temperature was attributed to a change in the emissivity of the surface as a consequence of the accumulation of PDMS in the air-oil interface. The presence of PDMS at the air-oil interface was confirmed for 100 ppm of PDMS, a concentration greater than the concentration necessary to form a monolayer of PDMS on the oil surface.