Medium, hydrocarbon

The slurry process is the oldest and still widely used method for manufacturing polymers of ethylene, propylene and higher a-olefins. In this process, the monomer dissolves in the polymerisation medium (hydrocarbon diluent) and forms a solid polymer as a suspension containing ca 40 wt-% of the polymer the polymerisation occurs below the melting point of the polymer. In slurry polymerisation, the temperature ranges from 70 to 90 °C, with the ethylene pressure varying between 7 and 30 atm. The polymerisation time is 1-4 h and the polymer yield is 95-98 %. The polymer is obtained in the form of fine particles in the diluent and can be separated by filtration. Removal of the catalyst residues from the polymer can be achieved by the addition of alcohol (isopropanol, methanol), followed by recovery and extraction of the catalyst residues. The polymer is freed from diluent by centrifuging and then dried. In the case of polypropylene manufacture, the atactic fraction remains in the diluent [28,37]. 

A charged molecule in high dielectric medium (water) experiences image forces at an interface towards low dielectric medium (hydrocarbon, air) [41]. This favors counter-ion binding, hence the polyelectrolyte is not charged near the interface. 

Medium Hydrocarbon Oils High MW Silicone Oil Hydraulic Oil... 

Most single chain surfactants do not sufficiently reduce interfacial tension at the oil/water interface to form MEs, furthermore they may lack the right molecular attributes (i.e., HLB) to act as cosolvents. To overcome such a hurdle, cosur-factant/cosolvent molecules are introduced to sufficiently lower the oil/water interfacial tension, fluidize the rigid hydrocarbon region of the interfacial film, and induce ideal curvature of the interfacial film. Typically, molecules with small to medium hydrocarbon chains (C3-C8) with a polar head group (hydroxyl, amine group, sulfoxide, or -oxides) that can effectively diffuse between the immiscible phases and the interfacial film are used [11]. 

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