The investigation of the dynamics of the phase transformation in triolein and oleic acid under pressure

An aim of our work is the understanding of processes happening during phase transformations under the pressure in triglycerides and unsaturated fatty acids. Particles of investigated liquids possess the double bond between carbon atoms, which causes the bended shape of the particle and makes its free rotation impossible. This property causes low temperatures of melting point and high temperatures of boiling and also investigated by us phase transformations. For study of the dynamics of phase transformation in these liquids we measured light transmission and light scattering at 90 degrees angle, temperature, permittivity and internal pressure versus time. We applied pressure using computer controlled pump with a stepping motor, which makes increase of the pressure steady. The phase transformation in oleic acid lasts several seconds, in triolein it lasts several minutes. We think that the elongated time of phase transformation is caused by a hooked shape of particles of triolein and the dynamics of that process is determined by the tangling of particles. We checked the influence of smaller particles of oleic acid on the phase transformation by investigating the mixture of these liquids.