Quality of Brazilian vegetable oils evaluated by (modulated) differential scanning calorimetry

Abstract

Vegetable oils are increasingly replacing fossil-oil-based polymers, and therefore aimed at being used in polymerization reactions from -20 to 100 A degrees C. Therefore, phase transitions and heat capacities in this temperature range should be well characterized to optimize processing conditions and energy inputs. By using the DSC analysis, only small primary correspondence or divergence between different oil types are seen as a function of their degree of unsaturation, but it does not clearly distinguish detailed features such as shoulder bands related to the separate melting processes of single fatty acid components. By using modulated DSC analysis, the combined analysis of reversing and non-reversing heat signals provides better results. The latter confirms that the melting is not a physical one-step process, but equilibrates between phase transitions and enthalpic reorganizations of the fatty acids that can be monitored separately. The specific heat capacities measured during modulated DSC are somewhat lower than traditional calorimetric measurements, but relate to the degree of unsaturation. The thermal behavior of palm-, soy-, sunflower-, corn-, castor-, and rapeseed-oil is discussed in relation to their composition, by applying a first or second heating scan

Hybrid palm-oil/styrene-maleimide nanoparticles synthesized in aqueous dispersion under different conditions

“…The oil composition and physical properties were previously characterized with spectroscopy (Samyn et al, 2012b) and thermal analysis (Samyn et al, 2012c): the PO has a iodine value of 54 g(I 2 )/100 g oil, peroxide value of 2.1 meq/kg, saponification value of 198 mg (KOH)/1 g oil and acid value of 0.10. The average fatty acid profile comprises 0.3% (C12:0), 0.7% (C14:0), 43.0% (C16:0), 4.5% (C18:0), 0.3% (C20:0), 0.3% (C16:1), 41.0% (C18:1), 0.1% (C20:1), 9.5% (C18:2), 0.4% (C18:3).…”

Synthesis of imidized nanoparticles containing soy oil under various reaction conditions

“…The oil composition and physical properties were previously characterized by spectroscopy [36], and thermal analysis [37]: it has a iodine value I.V. = 122 g(I 2 )/100 g oil, peroxide value = 2.7 meq/kg, saponification value = 195 mg (KOH)/1 g oil and acid value <1.…”

Characterization of a New α‐Linolenic Acid‐Rich Oil:Eucommia ulmoidesSeed Oil

“…The fatty acid composition of E. ulmoides seed oil is similar to that of flaxseed oil as reported in our previous studies (Zhang et al., ), whereas the melting thermogram of the 2 kinds of oil were quite different (Figure ). This may be attributed to different TAG profile and crystal forms, since the shapes of endothermic peaks are the result of overlapping effects from composition and polymorphism of the TAG (Samyn, Schoukens, Vonck, Stanssens, & Abbeele, ). In the range of temperature tested, that is, from –50 °C to 60 °C, the crystallization peak of E. ulmoides seed oil was observed at –41.3 °C and –23.9 °C, respectively.…”