Development of analytical system of composition- and molecular weight-distributions for organic functional materials

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The purpose of this research project has been the development of the analytical system to measure both the composition- and molecular weight distributions independently each other and successively. Temperature descending adsorption chromatography (TDAC) was designed and preheater tubing and a by-pass column were connected in a column-oven of the TDAC system. The performance of the system was estimated with styrene-methyl methacrylate copolymers. The mobile phase was a mixture of 1,2-dichlo-roethane and ethanol and a silica gel column was connected in the column-oven as the stationary phase. Column temperature at the begining was 60 ﾟC and a sample solution was injected into the system. The column temperature was decreased from 60 ﾟC to room temperature every 5 ﾟC and the fraction at each column temperature was monitored with UV detectors. Two UV detectors at 260 nm and 233 nm were used to monitor the effluent from the column: the wavelength at 260 nm was used to measure the composition and that at 233 nm the content of the copolymers. The results showed that the copolymers were separated according to their composition. Next step was to connect the size exclusion chromatography (SEC) system to the TDAC system. The effluent from the TDAC column at each column temperature was then introduced to the SEC system directly and molecular weight and molecular weight distribution of the copolymers were thus determined. With this TDAC-SEC system, both distributions, composition and molecular weight, could be measured directly without any fractionation technique.