Availability biodegradables

When looking at the life cycle of biodegradable plastics, two aspects are of particular importance the end-of-life options and the use of renewable resources in the material production (the major part of the currently available biodegradable plastic products are made of blends of fossil-based polymers and polymers derived from biomass). 

Phenobac is a commercially available biodegradation technology designed to treat industrial and manufacturing hydrocarbon waste discharges. The technology can be used for pretreatment... 

BioSolve is a commercially available biodegradable surfactant that is used to enhance bioremediation of petroleum hydrocarbons in soil and water. According to the vendor, BioSolve emulsifies and encapsulates petroleum-based products so that they become nonflammable and more readily bioavailable. Bioavailability is the combination substrate availability and substrate transport that allows for the initiation of bioremediation. 

There are broadly three classes of commercially available biodegradable polymers in existence. 

Most of the commercially available biodegradable devices are polyesters composed of homopolymers or copolymers of glycolide and lactide. There are also devices made from copolymers of trimethylene carbonate and e-caprolactone, and a suture product made from polydioxanone. 

Several other novel biodegradable polymer systems were also developed. One of these stems from the observation that many polymers used in medicine today were not initially designed for that purpose. It may be particularly useful to have available biodegradable polymers that are composed of, and will break down into, naturally occurring substances. One example is the synthesis of structurally new polyfamino acids) in which L-amino acids or dipeptides are polymerized by nonamide bonds (e.g., ester, iminocarbonate) involving the functional groups located on the amino acid side chains, rather than the extensively used approach involving the amino acid termini. 

Phosphate esters Wide range available. Biodegradable. Less effective than phosphonates. 

Table 1. Commercially available biodegradable synthetic polymers...

Chlorofonn 0.030 23 1 0.0004 1,733 0.03 23 Only one field study available. Biodegradation under nitrate-reducing conditions expected... 

A few commercially available biodegradable polymer-based articles. 

FUTURE DEVELOPMENTS 369 Table 9.1 Commercially Available Biodegradable Polymers... 

Fig. 17.2 Structure, trade names, and suppliers of main commercially and available biodegradable polyesters. Reproduced with permission (Bordes et al. 2009). Copyright of Elsevier...

Figure 13.12 Part representations for two commercially available biodegradable plastics.

Biopolymers have always been attractive materials in a variety of biomedical appU-cations including transdennal drug deUvery (Petrasic, 2011). Chitosan, a readily available biodegradable and biocompatible biopolymer, has been successfully used in fabrication of microcapsules intended for oral or topical medications. In a smdy of Lam et al., 5-fluoromucil was encapsulated in chitosan microcapsules and subsequently applied to a cotton fabric to a create transdennal delivery vehicle (Lam et al., 2012) 5-fluorouraciI (5-fluoro-lH-pyrimidine-2,4-dione) was chosen for its effective cytotoxic activity in the topical treatment of various forms of skin cancers. It was dissolved in calendula-infused oil and the mixture was then dispersed in the chitosan solution (in acetic acid) and stined into an emulsion. Sodium hydroxide... 

Poly(3-hydroxybutyrate) (PHB) 8 was a commercially available, biodegradable, non-linear polyester. Kumagai and Doi established that this polymer (M = 652,000, M /M =l.8) is immiscible with PCL (M =68,000, M /M =1.9) when solvent cast from chloroform [113]. Samples studied by DSC showed two glass-transition temperatures, identical with those of the individual components and invariant with composition. Mechanical properties of the blends were poor and tensile modulus and strength were minimal at 50 wt % of the components. PCL had a complex and accelerating influence on the rate of enzymatic degradation of PHB, the kinetics of which were correlated with scanning electron microscopy observations. 

A series of cellrrlose acetate films, differing in degree of srrbstitutiorr, was evalrrated in the bench-scale composting system [56]. Commercially available biodegradable pofymers such as pofy(hydroxybutyrate-co-valerate) (PHBV) and polycaprolactone (PCL) were included as... 

Figure 2. Chemical structures of available biodegradable polyesters.

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