Degradation of polymeric materials

In contrast to the extensive work of the pure thermal degradation of polymers, less fundamental chemical information is available on the mechanism of oxidative degradation of polymeric materials. As another point of... 

Zee, M.E. van der, Stoutjesdijk, J.H., Fell, H. and Feijen, J. (1998b). Relevance of aquatic biodegradation tests for predicting degradation of polymeric materials during biological waste treatment. Chemosphere, 36(3), 461 73. 

In comparison, no structural modification of model B was seen before 120 h of aging (80 °C). However, after 120 h two small doublets appeared in the NMR spectrum and several additional peaks became noticeable in the NMR spectrum. It was determined by NMR and IR spectroscopy that the hydrolysis products were an imide/carboxylic acid and an imide/anhydride. Model B was then aged for 1200 h at 80 °C to quantitatively determine the amount of hydrolysis products as a function of time. The relative intensity of the peaks due to carboxylic acid is constant after some time. The authors suggest that an equilibrium occurs between model B and the products formed during hydrolysis, and therefore, the conversion to hydrolysis products is limited to about 12%. This critical fraction is probably enough to cause some degradation of polymeric materials, but research on six-membered polyimides has remained active. 

In the absence of tin less asphaltene is produced which manifests itself as Increased yields of THF insolubles and preasphaltenes. At this time the activity of iron is not completely certain as no effects have been observed on the reactions of the coal derived products. However the proven ability of iron to both catalyze the reactions of some ethers while suppressing propagation reactions of phenoxy radicals suggests that its major activity is probably restricted to the first minutes of reaction (reactions 1,2) and to the slow catalytic degradation of polymerized material. The iron-tin synergism (1) can be interpreted as a co-operative action... 

Three methods that were used to measure the chemical changes associated with oxidative degradation of polymeric materials are presented. The first method is based on the nuclear activation of lsO in an elastomer that was thermally aged in an, 802 atmosphere. Second, the alcohol groups in a thermally aged elastomer were derivatized with trifluoroacetic anhydride and their concentration measured via 19F NMR spectroscopy. Finally, a respirometer was used to directly measure the oxidative rates of a polyurethane foam as a function of aging temperature. The measurement of the oxidation rates enabled acceleration factors for oxidative degradation of these materials to be calculated. 

K. Pielichowski and J. Njuguna. Thermal Degradation of Polymeric Materials. Rapra Technology, Rapra Technology Ltd., UK, 2005, p. 20. 

Pielichowski, K. and Njuguna, ). 2005.. Thermal Degradation of Polymeric Materials. Rapra. Technology, Schrewsbury, Shoropshire, UK. 

G. Ji-Dong. Microorganisms and microbial biofilms in the degradation of polymeric materials. Paper No. 03570, Corrosion 2003, NACE International, Houston, TX, 2003. 

Dr. Lattimer is an internationally recognized authority in the analytical characterization and degradation of polymeric materials. His research interests include mechanisms of crosslinking and pyrolysis of polymers, and the mass spectrometric analysis of polymeric systems. He is Editor of the Journal of Analytical and Applied Pyrolysis and a past Associate Editor of Rubber Chemistry and Technology. Dr. Lattimer is past Chairman of the Gordon Research Conference on Analytical Pyrolysis, and he received the ACS Rubber Division s Sparks-Thomas Award in 1990. He has won two Rubber Division Best Paper Awards, as well as three Honorable Mentions. 

P. Kaali, E. Stromberg, S. Karlsson, Prevention of biofilm associated infections and degradation of polymeric materials used in biomedical applications (INTECH Open Access Publisher, 2011), pp. 513-540... 

Pielichowski K, Njuguna J (2005) Thermal degradation of polymeric materials. RAPRA Technologies Limited, Shawbury, Surrey... 

In principle, degradation of polymeric materials can occur from a variety of causes such as... 

Budrugeac, P On the pseudo compensation effect due to the complexity of the mechanism of thermal degradation of polymeric materials, Polymer Degradation and Stability, 58 (1997), p. 69 - 76... 

Atomic oxygen plays a very important role in the degradation of polymeric materials in the Earth s space environment (cf. section 9.3). 

In summary, micro-organisms (MOs) can cause degradation of polymeric material individually or as co-cultures also known as consortiums. There is little evidence of the mechanical strength of polymeric materials being affected by MOs which allows for a wider scope of research into this area. 

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