Size exclusion chromatography weight data from

Novolac molecular weights were measured in THF at 35°C by high pressure size exclusion chromatography using a Waters Model 510 pump (flow rate=1.0 ml/min), 401 differential viscometer detector and a set of Dupont PSM 60 silanized columns. A universal calibration curve was obtained with a kit of 10 narrow molecular weight distribution, linear polystyrene standards from Toya Soda Company. Data acquisition and analysis were performed on an AT T 6312 computer using ASYST Unical 3.02 software supplied with the Viscotek instrument. 

The size exclusion chromatography for this study was done in the routine manner execept for the inclusion of an online viscosity detector called a Differential Viscometer <3> (Viscotek Corp., Porter, Texas, USAl. This instrument together with an RI concentration detector permits the calculation of intrinsic viscosities across the chromatogram. An IBM PC data system with software is also provided (5). The software acquires data from both detectors, and performs calculations of intrinsic viscosity and molecular weight distributions using the Universal Calibration Method. 

Number average molecular weight data from size exclusion chromatography for polymers A through E has been given previously... 

Size-exclusion chromatography [9] with a coupled molecular-weight-sensitive detection is a simple convenient method for characterizing dendrimers for which limited sample quantities are available. The polyether dendrimers increase in hydrodynamic radius approximately linearly with generation and have a characteristic maximum in viscosity. These properties distinguish these dendrimers from completely collapsed, globular structures. The experimental data also indicate that these structures are extended to approximately two-thirds of the theoretical, fully extended length. 

Cycloaliphatic resins were prepared by complete hydrogenation of selected aromatic resins. Molecular weight data were obtained by size exclusion chromatography, using a Styragel column set with THF as the mobile phase. Calculations were based on a polystyrene calibration. Glass transition temperatures were obtained by differential scanning calorimetry from the first break on the second heat. 

To illustrate the effect of the CTA on the polymer mass, data from ACOMP and size exclusion chromatography (SEC) experiments are combined in Rgure 12.2 [7]. Thus, MJfi data for reactions in which different amounts of CTA were used, computed based on Equation 12.1, are shown in the top portion of the figure whereas molecular weight distribution (MWD) from SEC experiments on reaction end products are shown in the bottom part. Both methods used show similar trends in the evolution of the polymer mass, that is, the higher the concentration of CTA involved in the reaction, the lower the is. 

Size exclusion liquid chromatography M) has been widely used to characterize distributions of molecular weights in polymer specimens. This paper describes a package of computer programs for automatic data collection and data reduction in size exclusion liquid chromatography (2). The programs and the environment in which they operate are carefully tailored to emphasize the interaction between the user and his data rather than the Interaction between the user and the computer. The system we describe differs from that described by Koehler et al. (J) in that all functions are performed by a stand-alone system. 

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