Polymer degradation experimental data

The final scope of the investigation of the quantitative regularities of adhesion and bio-overgrowth was obtaining macroscopic kinetic parameters of the biodamaging ability of polymers. The experimental data collected in Table 13 show the link between adhesion and the growth of biomass. Additional study is required to model media to better understand this type of degradation. 

Many experimental findings can at first glance be interpreted as some form of polymer degradation. But, scientifically valid data must try to make up the balance of the polymer and its degradation products to avoid false interpretation due to adsorption phenomena, inappropriate analytical tools or detection limits, or changes in its chemical identity. 

The kinetics of polymer oxidation in the solid phase (films) and in solutions of films, and of the polymers themselves, has been investigated. On account of the extremely large amount of theoretical and experimental data, only two fundamental cases, namely, autocatalytical oxidation in the presence of high and low concentrations of oxygen and the experimental principles in the investigation of degradation and cross-linking kinetics, are discussed in this chapter. 

As the conductive polymers are similar to various other materials such as amorphous polymers, inorganic intercalates, semiconductors, solid electrolytes and metals in one way or the other and these materials show wide range of degradation kinetics in different environments as well as dependence on temperature and the composition of the material. Hence, the predictions about degradation behaviour seem to be risky without experimental data. Also, one has to be very careful in extrapolating the available data which may lead to erroneous results. 

The complexity of the chemical structure of heterocyclic polymers, including PPO, which are very strong, thermally stable polymers, makes the study of their thermal and thermal-oxidative degradation difficnlt. The schemes suggested for their thermal degradation are in many cases only hypothetical, however, the available experimental data make it possible to delineate the major factors determining the thermal stability of these polymers [44-46]. 

Slagowski et al. (33) demonstrated the feasibility of HFIP as the SEC eluant for several polytetramethylene terephthalate polymers. Because polystyrene is not soluble in HFIP, no MW values were reported. In the same year Drott (7) used HFIP as SEC solvent for both nylons and polyesters. A polyelectrolyte effect had been observed for nylons but it was not a problem for polyesters. Drott also indicated that no polymer degradation occurred in HFIP by comparing the intrinsic viscosities of the initial and recovered PET samples. The direct calibration method was used by trial-and-error adjustment of the coefficients of a cubic polynomial until intrinsic viscosities of the samples calculated from SEC data (using the Mark-Houwink equation) agreed with experimentally measured values. 

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