Commercial Biodegradable Polymers

In response to the demand for biopol5mers, a number of new biopolymers have been developed which have been shown to biodegrade when discarded into the environment. Commercial biopolymers from various manufacturers are shown in Table 6.4. 

Each of the biopolymers listed in Table 6.4 has unique properties, benefits and weaknesses. 

Succinate Based Poly- Showa High Polymer Bionolle  

Starch and copolyes- BIOP Biopolymer Tech- BlOPar FG 

Loughmari, A. Hafid, A. Bouazza, A. El Bouadili, P. Zinck, and M. Visseaux, Journal of Polymer Science Part A Polymer Chemistry, Vol. 50, p. 2898, July 2012. 

---

Polyamides and polyesteramides are more recent arrivals to the commercial biodegradable polymer field. Copolymers of either glycine or serine with e-aminocaproic acid are biodegradable. For example, biodegradable polyaspartic acid was synthesized (95% yield) at low cost [Koskan, 1992]. A copolymer of butylene-adipate and e-caprolactam was recently introduced by Bayer as BAK 1095. The material has T = 125°C, density of 1070 kg/m, tensile modulus of 180 MPa, maximum strain at break of 400%, tensile stress at break of 25 MPa, and it fully degrades in 300 days under the ASTM standard conditions. 

A commercial biodegradable polymer, PLA reinforced with phosphate glass (PG) can be manufactured by the extrusion process followed by compression molding [40]. To limit polymer degradation, the mixture of PLA and PG was manufactured at 205 °C, with a screw rotation speed of 100 rpm and a dwelling... 

Table 19.43 Key properties of some commercial biodegradable polymer blends...

Tsutsumi C., Hayase N., Nakagawa K., Tanaka S., Miyahara Y. The enzymatic degradation of commercial biodegradable polymers by some hpases and chemical degradation of them, Macromol. Symp. 197 (2003)431. 

Figure 17 Physical properties map of commercial biodegradable polymers (shown in green) compared to commodity polymers.

There is finally a group of commercial biodegradable polymers, the blends of polymers from different origins. They have been formulated so that they offer interesting properties, limiting the amount of costly materials in their composition. In this family fall blends of starch with aliphatic polyesters, polylactic acid, polycaprolactone, polyvinylalcohol or cellulose acetate. The properties of starch (low cost material) are improved by the controlled addition of other more costly biopolymers. They will be described in section 1.2.1. 

Table 1.3 Processing possibilities of typical commercial biodegradable polymers... 

Based on these limitations, only a limited number of drug delivery systems based on biodegradable polymers have so far been successfully commercialized. One example is Lupron Depot one-month injectable microspheres of PLGA containing leuprorelin acetate (LH-RH agonist) for the treatment of endometriosis and prostatic cancer [31,32]. 

Another example where metabolic pathway engineering has made a dramatic impact is in the biodegradable polymer field. One of the most widely studied polymers in this family is poly-P-hydroxybutyrate (PHB) (64). A related member of the poly-P-hydroxyalkanoate (PHA) family commercialized by Imperial Chemical Industries (ICI), which later became Zeneca Bio Products,... 

A particular mention goes to Mater-Bi, produced by Novamont, who have revolutionised starch-based biomaterials for two decades. The commercial success of this biodegradable and biocompostable plastic relies on two main factors the scale economy that allows the reduction of costs, and the diversity of formulations to develop different end products (plastic bags, tableware, toys, etc.). More than 210 references in Chemical Abstracts are available on this (registered) keyword, and the number of patents related to different formulations and developments is also impressive. Mater-Bi can be essentially described as a blend of starch with a small amount of other biodegradable polymers and additives. The actual compositions are still known only by a very few people. 

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

Polysacharides such as starch are the most prevalent naturally biodegradable polymer in commercial use. Aliphatic polyesters such as polyhydroxyalkanoates (PHA) are also a family of easily biodegradable polymers found in nature that are beginning to find commercial use. 

In 2005, there were very few biodegradable polymer production plants operating on a fully commercial scale. NatureWorks LLC, Novamont, Rodenburg Biopolymers and BASF are currently the only major operators with significant production capacity. Nevertheless, the world biopolymers market has shown significant growth during the last five years or so, albeit from a very small base. 

---