Addition polymers degradation/biodegradation

Figure 2. Degradation/Biodegradation of Addition and Condensation Polymers.

PHAs can be either thermoplastic or elastomeric materials with variable mechanical, thermal stability and durability properties. They are water insoluble and impermeable to oxygen [14]. Due to the stereospecificity of the PHA synthase, all the hydroxyalkanoate monomers incorporated in the polymer are in the R(—) configuration, resulting in an optically pure polymer [15]. Additionally, they are biodegradable hence, they can be degraded and metabolized by microbes and by enzymes within the human body biocompatible, they do not generate toxic byproducts and some of them are piezoelectric, a property known to stimulate cell growth [4]. 

Hiltunen K, Seppala JV, Itavaara M, Harkonen M (1997) The biodegradation of lactic acid-based poly(ester-urethanes). J Environ Polym Degrad 5 167-173 Hossein AK, Seyed HJ, Ahmad A (2008) A review on homopolymer, blends, and nanocomposites of poly(trimethylene terephthalate) as a new addition to the aromatic polyesters class. Iran Polym J 17 19-38... 

ComCard International manufactures a degradable polylactic acid-based polymer called Mazin. It also contains a proprietary additive polymer. The lactic acid is derived from corn. The polymer has been tested at the University of Nebraska to verify its biodegradability. ... 

Addition polymers, such as polyolefins, on the other hand, have had limited testing in the laboratory and extensive testing in the real world in working landfill sites. They degrade initially by oxidation and subsequently by biodegradation. 

Other Addition Polymers. There are few studies on other reported polymer and plastic components of landfills. Poly(vinyl chloride) seems to be inert in landfill showing no degradation in real-world tests (23,24) and laboratory simulations (25). In the latter study, plasticizer migration occinred with its subsequent biodegradation. 

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