Silicone Aging Viscosity

Depending on the silicon-bonded substituents R in the starting compound, the viscosity of the solution increased considerably within 30 to 60 min (R = H, Cl) or within 24 h (R = CH3). The obtained gels aged readily and excess Bis as well as the couple product, Me3SiCl, which separated from the polymer, were distilled off under reduced pressure. The whole process is inexpensive, since excess bis and Me3SiCl can be recycled. Time-intensive processing steps are not required. 

Compared to a common thixotrope such as fumed silica, pulp provides equivalent viscosity at less than one tenth the weight in a typical epoxy resin. In addition, fluid viscosity is unaffected by further processing (agitation) or aging—in contrast to fumed silica modified resin where viscosity drops and is not fully recovered under similar conditions. Pulp can also provide reinforcement in an adhesive matrix as shown by the significant increase in tensile strength, modulus, and tear strength of both a PVC plastisol adhesive and a silicone sealant on the addition of pulp [137,140]. 

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