Polymer peak area correlation

Figure 10. Polymer peak area correlation with total solids (( ) polymerization 1 (A) polymerization 2 (O) polymerization 3)...

Amount of soluble polymer generated in this reaction (Figure 9) was only 18-19% solids, which was well below the 29% total solids found after reaction completion. Differences between calculated soluble solids and gravimetrically measured total solids were large, but variable, for all three polymerizations studied. Thus, amount of soluble polymer was not proportional to total solids. However, a good correlation between total solids and the sum of refractometer peak areas for both polymer peaks was obtained. Figure 10. This correlation included all three polymerizations and there was little or no batch bias. 

The next step in the calculation of n(A) is the correlation of trimer peak intensities with the number of specific triads in the polymer. A parameter K can be assigned as a coefficient to express the relationship between the pyrolysis peak area and the triad number. These K values can be obtained by calibrating through copolymers with known composition. A random copolymer of known composition is the best choice in this case since it produces all trimer peaks allowing good calibration. For each trimer type, a simple relation of the type ... 

To verify that this library was successfully synthesized, a portion of the resin was removed, and the compounds were cleaved from the polymer with trifluoroacetic acid and analyzed with HPLC electrospray ionization mass spectrometry. All the compounds shown could be identified. On cyclo-addition of the maleimides, endo/exo isomers and -in the case of the vinylsulfones - regioisomers were obtained. This led to complex chromatograms of isomeric compound mixtures co-elution often occurred. Quantification of the single compounds was not possible, and the peak area in the UV trace (detection at 214 nm) did not correlate with those of the total ion current chromatogram in the mass spectrum. 

The indentation test is one of the simplest ways to measure mechanical properties of a material. The micromechanical behavior of polymers and the correlation with microstrnctnre and morphology have been widely investigated over the past two decades (23). Conventional microindentation instruments are based on the optical measnrement of the residual impression produced by a sharp indenter penetrating the specimen surface under a given load at a known rate. Microhardness is obtained by dividing the peak load by the contact area of impression. From a macroscopic point of view, hardness is directly correlated to the yield stress of the material, ie, the minimnm stress at which permanent strain is produced when the stress is snbseqnently removed. 

As a rule, in a mixed mobile phase a solvent peak appears near the void volume of the column. The appearance of the solvent peak may due to one of several effects, the first of which is the preferential solvation of polymers [172]. After dissolution in a mixed solvent, the polymer binds into its solvation shell one part of mixture to a larger extent. After the separation of the solvated polymer from rest of injected solvent, the solvent peak appears on chromatogram as was demonstrated by SEC [172] and under suitable condition [173] its area, or height, may be correlated with coefficient of preferential solvation [ 172]. An evaporation of one component from the sample bottle or displacement effects may also lead to appearance of a solvent peak [173]. The solvent peak represents a local change of composition of the mobile phase. Under critical conditions small changes of the mobile phase composition (for example, 0.1 % wt.) have a large influence on polymer retention, thus the solvent peak could influence the elution of the macromolecules. If so, this could imply that a tabulated critical composition is not precisely that, which really correspond to the critical conditions. The real, acting critical composition of eluent may be, and likely is, the composition somewhere, in the middle, of the solvent peak. The presence of the solvent peak influences especially pronouncedly the elu-... 

Conversion andi p data may also be obtained using spectroscopic techniques such as Raman spectroscopy (73-75) and infrared spectroscopy (15,50,73,75-77). Here, peaks in these spectra correlate to functional groups within a molecule. As the monomer is converted to polymer, the peaks associated with the 0=C bonds decrease. The conversion in the system may be calculated by ratioing this peak height or area at any point in time to the initial peak height or area, as shown in Figure 8 ... 

---