4 TYPES OF DEGRADABLE PLASTICS
1. Photodegradable bioplastics
Photodegradable bioplastics have light sensitive group incorporated directly into the backbone of the polymer as additives. Extensive ultraviolet radiation (several weeks to months) can disintegrate their polymeric structure rendering them open to further
bacterial degradation
2. bio-based bioplastics
The Business-NGO (non-government organization) Working Group for Safer Chemicals and
Sustainable Materials defines bio-based bioplastics as “plastics in which 100% of the carbon is derived from renewable agricultural and forestry resources such as
corn starch, soybean protein and cellulose”
3. Compostable bioplastics
Compostable bioplastics are biologically decomposed during a composting process at a similar rate to other compostable materials and without leaving visible toxic remainders. In order to designate a plastic as bio-compostable, its total biodegradability, its disintegration degree, and the possible eco-toxicity of the degraded material must be determined by means of standard tests
4. Biodegradable bioplastics are fully degraded by microorganism without leaving visible toxic remainders. The term “biodegradable” refers to materials that can disintegrate or break down naturally into biogases and biomass (mostly carbon dioxide and water) as a result of being exposed to a microbial environment and humidity, such as the ones found in soil, hence reducing plastic waste, whereas bio-based sustainable materials. The fourth types of bioplastics are rather promising because of their actual utilization by microorganism.
BIOPLASTIC MARKET
1. Researchers have developed the “plastic spectrum” to assist in decision-making about plastics selection.
2. Packaging films and containers bioplastics are particularly interesting, since most of these products have a relative short service life and end up in landfills. Biodegradable bioplastics have been found to possess wide range of properties, which find application in biomedical field like making bone plates and screws, in drug delivery carriers and tissue engineering scaffolds.
3. The global bioplastics market is thought to be growing about 20%~25% per year. Approximately 10%~15% bioplastics of the total plastics market will increase its market share to 25%~30% by 2020. The bioplastic market reached over 1 billion US$ in 2007 and it will be over 10 billion by 2020.
BIODEGRATION AND STANDARDIZATION OF BIOPLASTICS
1. Biodegradability is an misused and abused term. Biodegradability results are strongly based on test conditions such as humidity, temperature and microorganisms. Also, the nature is different from laboratory conditions.
2. In the interests of environmental relevance, it is recommended that selection of the test methodology be based on potential fields of application of the test polymer and its end-of-life, which is compost, soil, fresh or marine water.
3. Biodegradability is an misused and abused term. Biodegradability results are strongly based on test conditions such as humidity, temperature and microorganisms. Also, the nature is different from laboratory conditions.
(Source: Journal of Civil Engineering and Architecture)
