Biopolymers and Their Application - Research Paper Example

Growing concern about environmental issues and the fact, that petroleum is a finite resource, increases attention to these materials. Twenty years ago synthesis of biopolymers cost more than a synthesis of polymers from petroleum. However, rising prices made this sphere more attractive. Besides, biopolymers may not only substitute traditional polymers but also possess new characteristics (biodegradability, extreme strength, possibility to obtain thin and firm films) (Sample).

There is three way of synthesizing biopolymers. The first way is the extraction and modification of natural polymers from plants. Examples of such materials are thermoplastic starch, derivatives of cellulose, and rubber. Rubber obtained from the rubber tree Hevea braziliensis is the first known polymer. The second pathway is the polymerization of bio-monomers. Polylactic acid (PLA), polyamides, polyurethanes, and polyesters can be obtained using this approach. The third pathway is the extraction of polymers produced by microorganisms. Polyhydroxyalkanoates (so-called PHA family) can be obtained using this approach (Rudin and Choi 528). Microorganisms can also produce monomers or raw materials that can be extracted and polymerized. For example, bioethanol can be produced from sugarcane starch, wheat, or corn through microbial strain and biological fermentation processes.  Afterward, ethanol is dehydrated over a solid catalyst to ethylene, which is polymerized to polyethylene (Babu, O'Connor, and Seeram 6).

The production of biopolymers uses well-known polymerization techniques. For example, polyamides or polyurethanes can be produced using free radical, cationic, olefin metathesis, and condensation polymerization. Polylactic acid is obtained from lactic acid by the combination of condensation polymerization and ring-opening polymerization or by one of the mentioned techniques separately. Polymers like PHA are synthesized by microorganisms (sometimes genetically modified) and extracted using centrifugation and press filtration. The biopolymer can be mixed with another biopolymer, a biodegradable synthetic polymer, or a non-degradable synthetic polymer. It permits to change of undesirable properties of biopolymer (thermal stability, strength) or creating a new biopolymer.  Additives like pigments, antioxidants antiseptics, and various inorganic fillers may be added to improve desirable properties of biopolymer (Rudin and Choi 529-531).

Biopolymers find their application in the food industry, medicine, agriculture, fishery, and environmental protection. Package from biopolymers is biodegradable and, thus, can substitute traditional polyethylene package. In medicine, biopolymers are used for controlled drug delivery, wound healing, as dental impressions, bone replacement or fixation implants, and bone cement. Biopolymers are widely used in the food industry as low-calorie food additives providing bulk and texture or protective films for food preservation (Babu, O'Connor, and Seeram 2-12).

It is expected that the number of newly synthesized biopolymers and their amount will grow. In their article, Babu, O'Connor, and Seeram indicated, “thanks to advancements in white biotechnology, the production of bio-based polymers and other chemicals from renewable resources has become a reality.” (12). the first generation of biopolymers was synthesized from food sources. The debates on food-versus-fuel turned the attention of scientists to the utilization of other renewable sources (like wood and cellulose products) and to microbial synthesis. New materials from renewable sources should become cost-effective, environmentally friendly alternatives to conventional polymers. This goal has to be achieved in further researches.