| Summary: | 碩士 === 逢甲大學 === 化學工程研究所 === 81 === The main purpose of this study is to investigate the floccula-
tion properties of polyurathane cationomer toward silica
suspens- ions. At first, the process which was used to
synthesize the water- based polyurethane cationomer by the
method of quaternizing poly- addition was decided. The
flocculants this study used was obtain- ed with different
concentration of reactant by the aboved process and the
intrinsic viscosity was measured by Ostwald Viscometer. In
the different values of pH and dosages of flocculant used, the
flocculating ability to silica suspensions were evaluated by
mea- suring the concentration of the residual particles in the
supern- atant after flocculation in terms of the turbidity.
From the experiments we gain the results that the polymer mol-
ecular weight decreases as the ratio of N-
Methyldiethanolamine (NMDEA) to Polyether Polyol(DL) increases.
Adequate flocculation, with clear supernatant,is achieved at
pH<7 but the residual turb- idity after flocculation is higher
than untreated suspensions' at pH value above 9. Another result
we found is that the subsidence rate decreases as the residual
silica in supernatant decreases.
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