Bio-Based Synthetic Rubbers: A Sustainable Shift in Plastics

Sustainable alternatives to natural rubber can solve environmental and supply chain challenges.

The rubber industry uses natural rubber (NR) from Hevea brasiliensis because of its strength. Yet, supply chain problems and environmental impact drive the need for sustainable alternatives. New biodegradable and bio-based rubbers offer promising solutions.

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Challenges in the Rubber Industry

Hevea brasiliensis grows in limited regions; therefore, the supply chain remains vulnerable to disease and climate change. Moreover, many plantations lack genetic diversity, further increasing the risk of diseases like South American Leaf Blight. Additionally, crops such as palm oil require more land, thereby reducing available space for rubber production. Meanwhile, the growing demand for synthetic rubbers derived from fossil fuels accelerates resource depletion and contributes to pollution. Furthermore, disposing of non-biodegradable rubber intensifies environmental pollution and exacerbates landfill issues.

Advancements in Biodegradable and Bio-Based Synthetic Rubbers

Biodegradable synthetic rubbers use biologically sourced materials. This improves renewability and reduces environmental impact. Key approaches include:

• Polymer Blending: Mixing natural materials like starch or cellulose with synthetic rubbers makes them easier to break down. Cellulose nanocrystals (CNC) make rubber stronger and more biodegradable. For example, adding CNC to styrene-butadiene rubber (SBR) makes it stronger and more flexible, which is useful in many products.
• Bio-Based Monomers: Using renewable materials like sugars and plant oils to make monomers help produce bio-based polymers like polyisoprene and polybutadiene. Blending bio-based monomers with synthetic rubbers reduces reliance on fossil resources and keeps performance strong. For example, blending poly(lactic acid) (PLA) with synthetic rubbers creates thermoplastic elastomers that are easier to recycle and have better mechanical properties
• Microbial Synthesis: Some bacteria make biodegradable polymers like PHAs used in rubber. These polymers break down safely in nature. Microbial synthesis uses renewable feedstocks, making it a sustainable way to create polymers.
• Chemical Modification: Epoxidation improves natural rubber’s oil resistance and material compatibility. Recent studies show that lignin and keratin-based additives strengthen rubber. For example, keratin from poultry waste acts as a biodegradable filler. It improves oil resistance in nitrile butadiene rubber (NBR) without affecting biodegradability.

How Plastics Enhance Rubbers

Bio-based rubbers and plastics use similar methods like polymerization, blending, and compounding. For example, blending PLA with EVA makes thermoplastic vulcanizates (TPVs). These materials stay flexible, recyclable, and partially biodegradable. Crosslinking increases their strength and flexibility, making them durable and ideal for many uses.

Bio-based fillers like starch, cellulose, and lignin connect rubber and plastics. For example, starch-filled rubber composites improve biodegradability while keeping good mechanical properties. Cellulose nanocrystals strengthen rubber and make it more biodegradable, improving its strength and flexibility. Lignin-based fillers also boost thermal stability and performance in synthetic rubbers. These advances show how using renewable materials in both rubber and plastic can drive innovation.

Future Perspectives

Thermoplastic vulcanizates (TPVs) are a promising development. These materials mix rubber’s elasticity with the recyclability of plastics. For example, TPVs made from PLA blends are stronger and more flexible, while also supporting sustainability goals.

Shifting to sustainable rubber production means improving material performance and making it cost-effective. Increasing microbial synthesis and using more bio-based monomers will be key. Researchers and industry must work together to speed up these changes.

Read the full paper here: Recent development of biodegradable synthetic rubbers and bio-based rubbers using sustainable materials from biological sources