Degradation durability

The new nanocomposite materials can be produced having improved physical, thermal and flammability properties with controlled durability, by having various types of nanoparticles. However, the degradation durability and toxicity of polymer-nanoparticles systems have to be evaluated for each nanoparticle with different polymers matrix under different environmental conditions for realizing the potential of nanomaterials. 

The slow rate of hydration for buried surfaces is desirable from a service point of view, but makes the study and evaluation of the durability of surface treatments difficult unless wedge tests (ASTM D3762) or similar tests are used to accelerate the degradation. As for the wedge test, the stress at the crack tip, together with the presence of moisture at the tip, make this a more severe test than soaked lap shear specimens or similar types and therefore a better measure of relative durability. 

Compared with tar, which has a relatively short lifetime in the marine environment, the residence times of plastic, glass and non-corrodible metallic debris are indefinite. Most plastic articles are fabricated from polyethylene, polystyrene or polyvinyl chloride. With molecular weights ranging to over 500,000, the only chemical reactivity of these polymers is derived from any residual unsaturation and, therefore, they are essentially inert chemically and photochemically. Further, since indigenous microflora lack the enzyme systems necessary to degrade most of these polymers, articles manufactured from them are highly resistant or virtually immune to biodegradation. That is, the properties that render plastics so durable... 

An alternative tactic to deal with the problem of polymer wastes is to make polymers degradable. The difficulty with this approach is that in making synthetic polymers degradable one of the greatest assets of these materials, namely their durability, may be eliminated. There is also the possibility that... 

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. 

L. Matisova-Rychla and J. Rychly, Inherent relations of chemiluminescence and thermooxidation of polymers, In R.L. Clough, N.C. Billingham and K.T. Gillen (Eds.), Advances in Chemistry, Series 249 Polymer Durability, Degradation, Stabilization and Lifetime Prediction. American Chemical Society, Washington, DC, 1996, p. 175. 

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