Conductometric titrations, acid sites

Latexes initiated with persulfate normally have terminal sulfate groups, but these can be hydrolyzed to alcohols and then oxidized to carboxyl groups. Terminal alcohol groups also result from hydrogen peroxide or hydroperoxide initiated polymerization. Ottewill and Shaw (22) first showed by electrophoresis that latexes stripped of salts and emulsifiers by dialysis have both strong and weak acid sites. Van den Hul and Vanderhoff (23) then found that conductometric titrations were most effective for... 

Figure 5. Conductometric titration of polystyrene latex with strong base. Key a, strong acid sites b, weak acid sites c, both strong and weak acid sites and d, weak acid and very weak acid sites (from Ref. 38.)...

Reactions at the Silicon Nitride - Solution Interface - A study was conducted to determine the extent of aqueous reactions at the silicon nitride-water interface. It was demonstrated that up to 27 days are required to stabilize reactions at the interface as indicated by Ph and particle electrophoresis measurements. A semiautomatic titrator was also purchased and set up to utilize acid-base titrations to study the silicon nitride-solvent interface. A particular emphasis of this work will be on the nonaqueous potentiometric and conductometric titration to determine the strength of acid and base sites on the silicon nitride surface. 

Reactions at the silicon nitride - solution interface - The use of potentiometric titrations in nonaqueous solvents indicates that there are possibly several different kinds of acid and base sites on the silicon nitride depending on the prior environmental history of the powd. The results are generally consistent with potentiometric titrations us d to evaluate the silicon dioxide surface. Future work will focus on further potentiometric as well as conductometric titrations on silicon nitride as well as model systems such as silicon dioxide. 

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