Molecular weight, degradation

This equation is based on a light scattering-intrinsic viscosity correlation for pentanediol based polyurethanes ( ). No molecular weight degradation in DMF was observed after aging the solutions for several days. 

The pollutant atoms or chemical functions are not eliminated by the degradation. For example, the chlorine in PVC is included in the low-molecular weight degradation products. Nevertheless, the pollution is globally reduced. 

Mass spectrometry Determination of molecular weight, degradation products, and contaminants PFGE [58]... 

Figure 2. A general scheme of various ways to modify lignin and its low molecular weight degradation products.

The solution behavior of poly(amic acids) was until recently, probably the least understood aspect of the soluble polyimide precursor. However, the advent of sophisticated laser light scattering and size exclusion chromatography instrumentation has allowed elucidation of the solution behavior of poly(amic adds). In the early days of polyimide chemistry, when most molecular weight characterization was based on viscosity determinations, a decrease in viscosity was associated with molecular weight degradation [15, 28, 29]. Upon combination of the two monomers an increase in the viscosity to the stoichiometric equivalence point is observed, followed by a decrease in the solution viscosity as a... 

Distillation under reduced pressure allowed separation of the TBP-diluent mixture components into three fractions diluent, 60% TBP, and distillation residue. The first two fractions can be reused in the process, but the residue contains high-molecular-weight degradation products, which are not eliminated by alkaline scrubbing. Distillation removes the degradation products that are responsible for poor hydrodynamic behavior and for the retention of radioactive products such as plutonium, zirconium, and ruthenium (143). 

Table 2 Low molecular weight degradation products identified in thermo- and photo-oxidised polyethylene ...

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