Bioplastics – Overview

Bioplastics harness the natural structures such as polymer networks that share the ability to be easily reshaped. Material – scientists are constantly tuning these natural structures to try and better replicate properties like durability and flexibility of conventional plastics.

As the awareness of rising oil prices and ecological responsibility increases, global business is now turning to implement bioplastics for a growing number of applications.

In general, bioplastics are plastics which derive from renewable agricultural and forestry resources such as corn, starch, protein, and cellulose. Differentiation from conventional petroleum based plastic relies mainly upon avoiding fossil fuel based polymers in their manufacture and the biodegradability of many bioplastic products.

Precision Dice Made From Biodegradable Cellulose Acetate; Image by Roland Scheicher

The main advantage of biodegradable plastics is their decomposition into carbon dioxide, methane, water, inorganic compounds, or biomass via microbial assimilation. Production, use and disposal of bioplastics are environmentally friendly compared to plastic production from petroleum due to a significant lowered emission of greenhouse gases. During the process of growing, the renewable resource absorbs the amount of carbon dioxide which is released while biodegradation of the biopolymers derived thereof. Nevertheless, manufacturing and processing of bioplastic materials is often still reliant upon petroleum as an energy and material source. This comes in the form of energy required for growing, harvesting, processing and transportation of the raw material to produce the bioplastic and finally of course, the production itself. The option of using renewable energy is considered to obtain petroleum independence. However, bioplasics significantly reduce hazardous waste caused by oil-derived plastics, which remain solid for hundreds of years.

To be considered as biodegradable, decomposition has to be measured by standardized tests, and take place within a specified period of time. The American Society of Testing and Materials (ASTM) has defined on what constitutes biodegradability in various disposal environments. Plastics that meet ASTM D6400, for instance, are biodegradable and compostable in commercial composting facilities. The ASTM 6400 standard is the regulatory framework for the United States and sets a less stringent threshold of 60% biodegradation within 180 days, within commercial composting conditions. The European equivalent standardized test criteria are EN 13432. This is arguably the most international in scope and compliance. The standard is required to claim that a product is compostable in the European marketplace. In summary, it requires biodegradation of 90% of the materials in a commercial composting unit within 180 days. While many bioplastics are compostable in commercial compost facilities, not all can be composted at home since they require specific conditions to degrade. Also some of fossil fuel based polymers are certified biodegradable and compostable due to the fact that biodegradability is directly linked to the chemical structure, not to the origin of the raw materials.

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