Degradation mechanisms hydro-biodegradation

Biomax is, according to the producer, a standard PET with addition of special monomers to allow degradation to take place. Comparable to PLA, the degradation mechanism is described as an initial attack of water to the special monomers which are sensitive to hydrolysis. Oligomers formed by this first abiotic degradation step can be transported into microbial cells and there be metabolised (Biomax is claimed to be (hydro/ biodegradable). 

BPEO means that in practice the same disposable product may end up in any one of the alternative options discussed above. Consequently the material used should ideally be accommodated in any of the procedures used. Thus for example, if a biodegradable product is to be mechanically recycled, it should be capable of being reprocessed at the same temperature as the rest of the polymeric waste. This has proved to be difficult in the case of many bio-based materials. Degradable polyethylene can be recycled normally at polyolefin processing temperatures [10] whereas most hydro-biodegradable polymers depolymerise or scorch at these temperatures and cannot be recycled with commercial synthetic polymers in standard reprocessing equipment. 

Poly(vinyl alcohol) (PVA), a well-known water-soluble and biodegradable polymer, has been used as an initiator for the microwave-assisted bulk ROP of s-caprolactone in a domestic microwave oven. The graft procedure proved to be an excellent method for functionalizing presynthesized polymers in order to specifically tailor their properties. In contrast to PVA, poly(e-caprolactone) (PCL) is hydro-phobic and degrades very slowly. The combination of the two polymers proves to be an attractive way to control biodegradability of the final material. In addition, the resultant poly(vinyl alcohol)-gra/f-poly(e-caprolactone) (PVA-g-PCL) had improved mechanical and thermal properties compared to the parent PVA. 

What affects the biocompatibility of a polymeric material are some inherent properties, such as material chemistry, molecular weight, solubility, hydro-philicity/hydrophobicity, absorption, degradation and erosion mechanism, etc. Consequently, given the complexity and the variety of biomedical applications for which biodegradable polymers are currently used, it underlines the need for developing a wide range of biodegradable materials available for requirements of each medical application. 

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