Degradation and stabilization

The method of formation of thermosetting IPNs governs the nomenclature for the system and some examples are the following. 

The melting of a poljmer for chemorheological measurements and processing often involves subjecting the material to shear in the presence of oxidizing agents, such as air. 

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K. Schwetlick, Mechanisms of Polymer Degradation and Stabilization (G. Scott, ed.), Elsevier Science Publishers, New York, Chap. 2, (1990). 

Horst mechanism of PVC stabilization. In fact, based on his observations Naqvi [134] has proposed an alternative model for the degradation and stabilization of PVC based on polar interactions within the polymer matrix, which will be discussed in the following section (Section VI). 

Naqvi [134] has proposed an alternative model to the Frye and Horst mechanism for the degradation and stabilization of PVC. At room temperature, PVC is well below its glass transition temperature (about 81°C). The low thermal stability of the polymer may be due to the presence of undesirable concentrations of like-poles in the more or less frozen matrix with strong dipoles. Such concentrations, randomly distributed in the polymer matrix, may be considered to constitute weak or high energy spots in the polymer, the possible sites of initiation of thermal dehydrochlorination. 

Every alternating atom in the PDMS chain is the electronegative oxygen, which makes it a polar polymer. The authors observed that at low loadings of PDMS, PVC is destabilized. This is to be expected according to the alternative model for degradation and stabilization of PVC put forward by Naqvi. But for compositions with 50% or more PDMS, both polymers are stabilized. No possible explanation can be given for this reversal in thermal stability at this time. 

N. M. Emanuel and A. L. Buchahenko, Chemical Physics of Polymer Degradation and Stabilization, VNU Science Press, p. 340(1987). 

K. S. Minsker, S. V. Kolesov, and G. E. Zaikov, Degradation and Stabilization of Polymers on the Base of Vinyl-chloride, Pergamon Press, Oxford, p. 526 (1988). 

N. Grassie, and G. Scott, Polymer Degradation and Stabilization, Cambridge University Press, Cambridge, p. 222 (1985). 

The degradation and stabilization of polymers are very important problems from the scientific and industrial points of view. A better understanding of their mechanism is necessary to achieve better stabilization. A small amount of compounds, called stabilizers, are added into the polymer matrix to retard degradation and to impart... 

Sivaram, S. and Singh, R. P. Degradation and Stabilization of Ethylene-Propylene Copolymers and Their Blends A Critical Review. Vol. 101, pp. 169-216. 

Polymer Degradation and Stability 75,No.l,2002,p.l85-91 STUDY ON METHANOLYTIC DEPOLYMERIZATION OF PET WITH SUPERCRITICAL METHANOL FOR CHEMICAL RECYCLING... 

Polymer Degradation and Stability 53,No.2, 1996,p.l89-97 THERMAL DEGRADATION OF MIXED PLASTIC WASTE TO AROMATICS AND GAS... 

Antony, P., Puskas, J.E., and Kontopoulou, M. The Rheological and Mechanical Properties of Blends Based on Polystyrene-Polyisobutylene-Polystyrene Triblock Copolymer and Polystyrene. Proceedings of MODEST, International Symposium on Polymer Modification, Degradation and Stabilization, Budapest, Hungary, 2002. 

Gillen, K.T., M. Celina, and R. Bernstein, Validation of improved methods for predicting long-term elastomeric seal lifetimes from compression stress-relaxation and oxygen consumption techniques. Polymer Degradation and Stability, 82(1), 25-35, 2003. 

Figure 9.2 500 MHz H NMR spectra of a commercial stabilised PE product solvent and temperature as in Figure 9.1. See Figure 9.1 for structural designations (S and P refer to residual solvent and polymer resonances, respectively). After Schilling et al. [48]. Reprinted from Polymer Degradation and Stability, 31, F.C. Schilling et al., 141-152, Copyright (1991), with permission from Elsevier...

E. Owen "Degradation and stabilization of PVC" Elsevier Appl. Sci. Publ. London 1984... 

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