Effect of Nano-Calcium Carbonate on Re-Agglomeration of Dealcoholized RTV-1 Silicone Rubber
The re-agglomeration in dealcoholized one-component room temperature vulcanized(RTV-1)silicone rubber was simulated in experiment.The effect of nano calcium carbonate on the re-agglomeration of silicone rubber was analyzed by thermo-gravimetric analyzer,scanning electron microscope,inductively coupled plasma spectrometer.The results indicate that the re-ag-glomerate part of the RTV-1 silicone rubber exhibits an enrichment of magnesium,in the form of fatty acid magnesium.Methanol is the main cause contributing to the re-agglomeration in silicone rubber.Re-agglomeration cannot occur without the presence of methanol,and magnesium fatty acid accelerates the enrichment of methanol,thereby leading to a more rapid and severe re-ag-glomeration.The magnesium fatty acid appears during the surface treatment of nano-calcium carbonate.An increase in the con-centration of magnesium ions in the liquid phase of nano-calcium carbonate suspension leads to a higher formation of magnesium fatty acid,exacerbating the re-agglomeration in silicone rubber.The presence of magnesium salts,corresponding to common fatty acids,in nano-calcium carbonate surface treatment agents can expedite the re-agglomeration,and the extent of re-agglomeration is associated with the solubility of magnesium fatty acid in methanol;a higher solubility in methanol leads to a more severe reag-glomerate situation.
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