Aspects of Polymer Degradation

Fundamental Aspects of Polymer Degradation By High-Energy Radiation... 

McNeill, I. C. (1991). Fundamental aspects of polymer degradation. In Polymers in... 

A number of solutions have been forthcoming as evidenced by the large number of publications and patents concerned with methods for environmentally degrading polymers. In a publication of the Plastics Technical Evaluation center at Picatinny Arsenal entitled "Environmentally Degradable Plastics A Review" and authored by Mrs. Joan Titus, much of the past history up to about February 1973 has been covered. Also papers presented at the conference on "Degradability of Polymers and Plastics" in London in November, 1973 have summarized many of the fundamental and practical aspects of polymer degradation. 

Volume 14 deals with all aspects of polymer degradation, classified on the basis of the method of initiation for the process. Thus, Chapter 1 covers thermal degradation, Chapter 2 radiolysis initiated by high-energy radiation such as X- and 7-radiation and electrons, Chapter 3 photodegradation arising from exposure of polymers to visible or ultraviolet radiation and Chapter 4 discusses oxidative degradation, oxidation and photooxidation. 

Degradation and disappearance of a biodegradable polymer matrix occurs in a sequence of steps. Some of these steps are understood reasonably well as a consequence mathematical expressions can be used to describe some aspects of polymer degradation and drug release. These mechanisms will be illustrated using the pLGA system. 

McNeill, I. C. (1992). Fundamental aspects of polymer degradation. In Postprints of Polymers in Conservation Manchester 17-19 July 1991 (N. S. Allen, M. Edge and C. V. Horie, eds.) pp.14-31. Royal Society of Chemistry. 

G. Zaikov, Quantitative aspects of polymer degradation in the living body, J. Maaomol. Sci. Rev. Macromol. Chem Phys. 25 (1985) 551-597. 

Rivaton, A., Gardette, J.L., Mailhot, B., and Morlat-Therlas, S. (2005) Basic aspects of polymer degradation. Macromol. Symp., 225,129-146. 

The above results have illuminated important aspects of polymer degradation in general, and of ionomeric membranes in particular evidence was provided that both the end chains... 

Other aspects of stabilization of acetal resins are briefly discussed under processing and fabrication. Reference 15 provides a more detailed discussion of the mechanism of polymer degradation. 

Bomp R, Meyers J, KvovarB, Kim YS, Mukundan R, Garland N, Myers D, Wilson M, GarzonF, Wood D, Zelenay P, Mote K, Stroh K, Zawodzinski T, Boncella J, McGrath JE, Inaba M, Miyatake K, Hori M, Ota K, Ogumi Z, Miyata S, Nishikata A, Siroma Z, Uchimoto Y, Yasuda K, Kimijima Ki, Iwashita N. 2007. Scientific aspects of polymer electrolyte fuel cell durability and degradation. Chem Rev 107 3904-3951. 

Kabatek, Z., Gas, B. and Vohlidal, ]., Gel permeation chromatography of polymers degrading randomly in the column. Theoretical treatment and practical aspects, /. Chromatogr. A, 786, 209,1997. 

As is evident in the many examples selected in this chapter to illustrate the molecular characterisation and analysis of polymer degradation and oxidation processes, almost, without exception, each study or investigation cited has involved use of more than one analytical method or characterisation technique, often many more than two. This clearly emphasises the importance of using a multi-technique approach to provide supportive, complementary and confirmatory information, since each technique or method yields a different aspect of the degradation/oxidation process in polymers. 

There are 22 chapters in the book and they cover the most important aspects of polymers as drugs, prodrugs, dmg delivery systems, and in situ prostheses. The major features promulgated are synthesis, derivatization, degradation, characterization, application, and evaluation techniques as well as new biodegradable materials, assemblies, hydrogels, telechelic polymers, derivatized polysaccharides, micro- and nanoparticles, mimetic... 

A.J. Chirinos-Padrdn, Aspects of polymer stabilisation. In Handbook of Polymer Degradation, S. Halim Hamid, M.B. Amin, and A.G. Maadhah (eds.), Dekker, New York, 1992, Chapter 8, pp. 261-303. 

This represents the key aspect of polymer fire retardancy using hydrated fillers, and involves energy changes that occur on the decomposition of the filler, related heat capacity effects, which influence the degradation profile of the polymer and thermal barrier formation resulting from the residue remaining from degraded filler. 

Yet another important aspect of polymers is associated with environmental effects polymers can degrade at moderately high temperatures and through moisture absorption. Absorption of moisture from the environment causes swelling in the polymer as well as a reduction in its glass transition temperature, Tg. Polymers can also undergo chain scission when exposed to ultraviolet radiation. 

Chirinos-Padron, A.J. Allen, N.S. Aspects of polymer stabilization. In Handbook of Polymer Degradation Hamid, S.H., Amin, M.B., Maadhah, A.G., Eds. Dekker New York, 1992 Chapter 8, 261-303. 

Starnes, W. H. (1981) Mechanistic aspects of the degradation and stabilisation of poly(vinyl chloride), in Grassie, N. (Ed.) Developments in Polymer Degradation - 3, London Elsevier Applied Science. 

This aspect of the kinetics of polymer degradation has been surveyed by Jellinek and Luh [22]. Three types of diffusion controlled reaction have been discussed. 

The theoretical aspect of polymer crosslinking developed by Stock-mayer [20] and Flory [21] was extended by Charlesby [2, 22—24] to the irradiation of polymers. Other developments have been given by Shultz et al. [25] and more recently by Saito et al. [26]. The theory of polymer degradation has been developed by many other authors [27—36]. The methods developed by Charlesby will be briefly reported here and his notations will be adopted. Later theories will then be outlined. 

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