The polypropylene additives were extracted by dissolution-precipitation and Soxhlet. The Soxhlet method was adapted for the extraction of phosphorous antioxidants. The RP HPLC method with quaternary gradient elution separated five chemical groups of additives: lower molecular mass di-tert-butyl phenol (D.T.B.P.), hindered amine light stabilizers (Tinuvin 326), hindered phenolic antioxidants (Irganox 1010) and phosphorous antioxidants (Irgafos 168 and Ultranox 626) with their degradation products.

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Propylene oligomers were isolated from polymer matrix by dissolution precipitation and Soxhlet methods and characterized by Fourier transform infrared spectrometry, ultraviolet, high-performance liquid chromatography, and gel permeation chromatography. Both extracts showed that these hydrocarbon chemicals have a maximal absorption at 210 nm and are eluted from a C8 column with a strong mobile phase (tetrahydrofuran). However, their average molecular weights are different depending upon the quality of extraction: the fraction obtained by the dissolution-precipitation method is homogeneous in molecular weight, whereas the one obtained by Soxhlet extraction has a higher polydispersity index (M n /M w ). The specific migration test of propylene oligomers in a food simulant (isooctane) shows total diffusion within 60 min.

Cavitation phenomenon is defined as the process of rupturing any liquid by a decrease in pressure at nearly constant temperature. The cavities driven by the flow in a region of high pressure will implode and generate high pressure pulses leading eventually to erosion and vibration. But in supercavitation the bubbles produced by cavitation combine to form a large, stable bubble region around the supercavitating object. This phenomenon decreases the drag on the supercavitating body. Experimental testsware performed at 2-D unsteady flow for two wedge shaped bodies made before in laboratory and cavitation inception and its development were captured by a high speed camera. Then this cavitation regime around the wedge was studied numerically. In these cases CFD code was developed to simulate the unsteady and incompressible flow based on finite volume, 2D transient, with different boundary conditions. These numerical models which were evaluated experimentally depicted the capabilities of this CFD code to simulate this flow field cavitation inception, its development, and drag force in all cases. In this study we worked on two different geometries. Whether the cavitation is occurred at nose of body or not is worthy and studied by the above mentioned scheme. Moreover, we wanted to find the supercavitation regime and drag reduction for these two bodies.

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