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Fig. 2.7 Effects of methanol and water on the first Michael addition of surface amino groups with MA

2.3.2.5 Effects of Reaction Conditions on the Grafting of Hyperbranched Poly(Amidoamine)

The effects of reaction time and temperature on the grafting of hyperbranched poly(amidoamine) onto silica nanoparticle were investigated. The results are shown in Table 2.3. As shown in Table 2.3, the percentage of grafting increased with increase in reaction time, but the amount of ungrafted polymer also increased. This indicates that the formation of ungrafted polymer was accelerated because of thermal polymerization of MA during the prolonged reaction time. On the other hand, the grafting of poly(amidoamine) onto silica nanoparticle surface decreased at higher temperature.

2.3.2.6 Effect of Surface Amino Group Content on the Grafting of Hyperbranched Poly(Amidoamine) onto Silica Nanoparticle

Table 2.4 shows the effect of amino group content on the grafting of the hyperbranched poly(amidoamine) onto silica nanoparticle surface. It was found that the percentage of grafting with repeated reaction cycles of two times increased with increase in the initial amino group content on the surface. However, R (ratio of experimental value to theoretical value) decreased with increase in amino group content on the surface as grafting site.

Table 2.3 Effect of reaction conditions on the grafting of hyper-branched poly(amidoamine) onto silica nanoparticle surfacea

Temperature

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