Biodegradable polymers hydrolysis

It should be pointed out that the raw materials for VAM and its related polymers (i.e. ethylene and acetic acid) are produced from fossil resources, mainly crude oil. It is possible to completely substitute the feedstock for these raw materials and switch to ethanol, which can be produced from renewable resources like sugar cane, com, or preferably straw and other non-food parts of plants. Having that in mind, the whole production of PVAc, that nowadays is based on traditional fossil resources, could be switched to a renewable, sustainable and C02-neutral production process based on bioethanol, as shown in Fig. 3. If the vinyl acetate circle can be closed by the important steps of biodegradation or hydrolysis and biodegradation of vinyl ester-based polymers back to carbon dioxide, then a tmly sustainable material circle can be established. 

Chiellini E, Corti A, Del Sarto G, D Antone S (2006) Oxo-biodegradable polymers - effect of hydrolysis degree o biodegradation behaviour of poly(vinyl alcohol). Polym Degrad Stab 91 3397-3406... 

Incorporation of F-chain end-groups into biodegradable polymers can help modulate their biodegradation (e.g., the hydrolysis rate of polyesters) and drug release [68], Surface treatment of polymer for example, poly(lactic-co-glycolic acid)... 

Crommen, J.H.L., Schacht, E.H., and Mense, E.H.G. (1992). Biodegradable Polymers. 2. Degradation Characteristics of Hydrolysis-Sensitive Poly[(Qrgano)Phosphazenes]. Biomaterials, 13, 601-611. 

Biodegradable polymers used in the field of controlled drug delivery are typically degraded by hydrolysis [38]. In addition, some biomedical polymers are enzymatically degradable [35,39]. Many factors are known to influence the bio-... 

As pointed out by Heller (2), polymer erosion can be controlled by the following three types of mechanisms (1) water-soluble polymers insolubilized by hydrolytically unstable cross-links (2) water-insoluble polymers solubilized by hydrolysis, ionization, or protonation of pendant groups (3) hydrophobic polymers solubilized by backbone cleavage to small water soluble molecules. These mechanisms represent extreme cases the actual erosion may occur by a combination of mechanisms. In addition to poly (lactic acid), poly (glycolic acid), and lactic/glycolic acid copolymers, other commonly used bioerodible/biodegradable polymers include polyorthoesters, polycaprolactone, polyaminoacids, polyanhydrides, and half esters of methyl vinyl ether-maleic anhydride copolymers (3). 

DuPont offers a family of biodegradable polymers based on polyethylene terephthalate (PET) technology known commercially as Biomax. Proprietary monomers are incorporated into the polymer, creating sites that are susceptible to hydrolysis. At elevated temperatures, the large polymer molecules are cleaved by moisture into smaller molecules, which are then consumed by naturally occurring microbes and converted to carbon dioxide, water and biomass. Biomax can be recycled, incinerated or landfilled, but is designed specifically for disposal by composting. 

Chitosan Chitosan is a nontoxic, biodegradable polymer obtained by hydrolysis of chitin, a natural polysaccharide that is a chief component of the crustacean exoskeleton. Unmodified chitosan is soluble in acidic media and has significant muco-adhesive properties. 

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