Round particle formation mechanism

The Stober route (8) is a well-known method for providing submicro-meter- or micrometer-sized silica particles by hydrolysis and condensation of silicon alkoxide an excess of base and water is used in the reaction. Compared with this method, ours has quite different reaction conditions, namely, the use of a limited amount of water and a large amount of acid. In contrast to the reaction of silicon alkoxide with a large amount of water in basic conditions, Sakka and Kamiya (9) noticed from the measurement of the intrinsic viscosity of silica sols that linear particles or polymers, not round particles, are formed with acidic conditions and the addition of a small amount of water. Therefore, the reaction conditions for this method for producing round micrometer-sized particles is new, and the mechanism of formation of round particles is of interest. 

Effect of H2O and Hcl Content of the Mechanism of the Formation of Round Particles... 

Thus, the formation of the two-phase system by the method with PER ensures optimal values of some of the physical-mechanical characteristics. These conclusions are confirmed by the results of electron-microscopic studies. With chemical bonds between the epoxy polymers and the rubber particles, the developing crack does not pass round the rubber particle but penetrates it, which causes delocalization of stresses at the tip of the crack and results in improvement of the physical and mechanical properties of the ERC. 

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