by What are biopolymers?
Biopolymers, also known as natural polymers, are polymers that are produced by living organisms. They are distinct from synthetic polymers in their origin, structure and biological role. Most biopolymers can be degraded by microorganisms into biomass, carbon dioxide, water and natural inorganic nutrients. This ability to biodegrade makes them a sustainable alternative to petroleum-based plastics that are manufactured from non-renewable fossil fuels and take hundreds of years to degrade in the environment.
There are two main categories of biopolymers – polynucleotides like DNA and RNA, and polyesters like cellulose, starch, chitin, proteins etc. DNA and RNA are nucleic acid polymers that store and transmit genetic information in all living organisms, while cellulose, starch and chitin are structural biopolymers that provide strength and support to plant and animal tissues. Proteins are functional biopolymers that play roles in structure, movement, transport, storage, and catalysis.
Potential for replacing plastics
With the global focus increasing on moving away from fossil fuels to more eco-friendly and sustainable materials, biopolymers are seen as a promising alternative to plastics in many applications. Some of the key reasons for this are:
– Renewability: Biopolymers are produced from biological raw materials like agricultural byproducts and waste. This renewable feedstock reduces dependency on non-renewable petroleum sources.
– Biodegradability: Most biopolymers can break down completely at the end of their use into water, carbon dioxide and biomass through the natural action of enzymes secreted by microbes in the environment. This prevents the accumulation of plastics in landfills and oceans.
– Comparable properties: Biopolymers like polyhydroxyalkanoates, polylactic acid and cellulose derivatives have properties very similar to common plastics like polyethylene, polypropylene and polyester. This allows their usage as direct replacements without requiring major changes in manufacturing processes.
– Carbon footprint: The production, usage and disposal of biopolymers results in a much lower carbon footprint compared to conventional plastics. Some like PLA even sequester carbon from the atmosphere during growth of their feedstock.
Applications and commercialization
Biopolymers are already making inroads in various applications that were previously dominated by petroleum-based plastics. Some examples are:
Packaging
Bioplastics like PLA, starch blends, cellulose and lignocellulose derivatives are being increasingly used for food packaging, disposable tableware, bags and wrappers. Major brands have pledged to make their packaging more sustainable by incorporating biopolymers.
Textiles
Biodegradable fibers from materials like polylactic acid, polyhydroxyalkanoates and proteins are being commercialized for clothing, home textiles and hygiene products like diapers to reduce microplastic pollution from synthetic fabrics.
3D printing
Biopolymer filaments made of PLA, PHA, cellulose and silk are very popular materials for 3D printing due to their printability, strength and environment-friendly profile. Several manufacturers now offer bio-based filaments.
Automotive
Car manufacturers worldwide are developing bioplastic components for interior trim parts, seat components and exteriors using biopolymers like PLA and thermoplastic starch to lessen vehicle weight and carbon footprint. Tests show the materials withstand high temperatures adequately.
However, increased production and integration of biopolymers faces challenges in terms of high manufacturing costs compared to fossil fuel based polymers currently. Also, more research is required to enhance some mechanical properties to enable a wider range of structural applications. Continuous improvements in technology, economies of scale in production and policy support can help biopolymers progressively take over more areas dominated by plastics.
