Silicone fluids are widely used in industry. The most common silicone fluids used are dimethylsiloxane fluids, which are typically low molecular weight cyclic molecules. However, high molecular weight and highly branched fluids are also used in many applications.
The phenomenon of a viscoelastic liquid climbing a rotating rod, known as the Weissenberg effect, has been observed in polymer solutions, and in pituitous silicone fluids as described by Starch et al. (US Pub. No. 2012/0220549 A1). This behavior is representative of entanglements between polymer chains that develop under shear stress. These pituitous silicone fluids are high molecular weight, highly branched organopolysiloxanes that are used in personal care products and are shown, for example, in FIGS. 1A and 1B.
These branched organopolysiloxanes are obtainable by the reaction of organohydrogencyclosiloxanes with alkenyl functionalized polydimethylsiloxanes. However, these pituitous silicone fluids are formed using a process that is very sensitive to stoichiometry. For this reason, it is difficult to produce consistently high yields of predictable products. Moreover, these highly branched organopolysiloxanes are sterically hindered such that large side chains are difficult to add. Therefore, there remains opportunity for improvement.
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