Computerized HDC

In this publication monitoring of different particle growth patterns during latex polymerizations using the high speed computerized HDC will be described for S/B latexes. Kinetic information will not be dealt with in this paper. 

Prior to the measurements of the different reactor latex samples the computerized HDC was calibrated for particle-size using the standard procedure (3) and also for particle-size distribution quantification. For the particle-size distribution calibration two different particle-size monodisperse carboxylated S/B latexes were polymerized. Various mixtures of these latexes were prepared by blending the large 2100A and the small 700A latexes in different ratios by weight 60/40, 70/30, 80/20 and 90/100 respectively. 

The relative amount of each latex (Vj, Vg) in the different blends, as determined by HDC are shown in Figures 2 and 3. There was excellent correlation between the actual and the measured quantities of each component in the different binary mixtures. This calibration for particle-size distribution demonstrated that the computerized HDC could be used to determine the relative amount of each latex in the various binary mixtures within IX. 

Also it should be noted that this computerized HDC analysis for particle-size measurements oi these latexes was within 2% oi that measured by TEM. Since the particle-size determinations by the two different methods were in close agreement it was accepted that the HDC eluant composition was minimizing the particle-swelling phenomenon of the carboxylated S/B particles. 

Computerized HDC for Monitoring the Latex Emulsion Polymerization Particle Growth Patterns. 

The computerized HDC technique was used to quantify the relative amounts of the large 2100A and small 700A monodisperse latexes in different binary mixtures. The HDC measurements for the relative amounts of the two components were within 1% of the actual amounts. 

In the earlier publications (1,2) it was shown how hydrodynamic chromatography (HDC) could be applied in the study of polymer latexes to determine particle-size. An improved technique for the HDC was developed which utilized higher efficiency and resolving power columns to significantly reduce the analysis time (3). A high speed integrated computer was included in this improvement so that both particle-size and particle-size distribution of latexes could be quantified in the relatively short period of time. This high speed computerized version of the HDC has been used extensively for measurements on the final latex. 

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