Polylactic Acid (PLA)

Polylactic Acid (PLA) is one of the most widely used and commercially successful bioplastics available today. As a thermoplastic polyester derived from renewable biomass, PLA represents a significant step forward in sustainable plastic alternatives.

What is PLA?

PLA is a biodegradable and bioactive thermoplastic aliphatic polyester derived from renewable resources such as corn starch, cassava roots, chips or starch, or sugarcane. Unlike conventional plastics derived from petroleum, PLA offers a more environmentally friendly alternative while maintaining many of the properties that make plastics so useful.

Production Process

Raw Materials

• Corn starch (most common source)
• Sugarcane
• Cassava root
• Sugar beet
• Wheat starch

Manufacturing Steps

1. Extraction: Starch is extracted from the biomass source
2. Fermentation: Starch is converted to lactic acid through bacterial fermentation
3. Polymerization: Lactic acid molecules are linked together to form long chains (PLA polymer)
4. Processing: The polymer is processed into pellets for manufacturing

Properties and Characteristics

Physical Properties

• Appearance: Clear, transparent to translucent
• Density: 1.24 g/cm³
• Melting Point: 150-160°C (302-320°F)
• Glass Transition Temperature: 60-65°C
• Tensile Strength: 50-70 MPa

Key Characteristics

• Biodegradable: Under industrial composting conditions (58°C, high humidity)
• Compostable: Breaks down into water, CO₂, and organic matter
• Renewable: Made from plant-based materials
• Processable: Can be processed using conventional plastic equipment
• Food Safe: FDA approved for food contact applications

Advantages

Environmental Benefits

• Renewable Source: Made from annually renewable crops
• Lower Carbon Footprint: Reduced greenhouse gas emissions compared to petroleum-based plastics
• Biodegradable: Decomposes under proper composting conditions
• Compostable: Can be processed in industrial composting facilities

Technical Advantages

• Easy Processing: Compatible with existing plastic manufacturing equipment
• Good Printability: Excellent for 3D printing applications
• Clarity: Can achieve high transparency
• Barrier Properties: Good moisture barrier characteristics
• Food Safety: Safe for food contact applications

Limitations

Performance Limitations

• Heat Sensitivity: Lower heat resistance compared to conventional plastics
• Brittleness: Can be more brittle than some petroleum-based alternatives
• Moisture Sensitivity: Properties can degrade in high humidity environments
• Limited Barrier Properties: Poor barrier to oxygen and water vapor

End-of-Life Considerations

• Industrial Composting Required: Needs high-temperature industrial composting (not home compostable)
• Limited Recycling: Separate collection and processing required
• Contamination Issues: Can contaminate conventional plastic recycling streams

Applications

Packaging

• Food containers and trays
• Disposable cups and lids
• Clamshell packaging
• Flexible films and bags
• Bottle applications

Consumer Products

• 3D printing filament
• Disposable cutlery
• Plates and bowls
• Straws and stirrers
• Shopping bags

Medical and Healthcare

• Surgical sutures (bioabsorbable)
• Drug delivery systems
• Medical implants (temporary)
• Surgical clips and pins

Textile Applications

• Non-woven fabrics
• Clothing fibers
• Carpeting
• Upholstery

Market and Economics

Global Production

• Current global production capacity: Over 600,000 tons annually
• Leading producers: NatureWorks (USA), Total Corbion (Netherlands), COFCO (China)
• Growing market with 15-20% annual growth rate

Cost Considerations

• Generally 20-50% more expensive than conventional plastics
• Costs decreasing with scale and technological improvements
• Price competitiveness improving with rising oil prices

Environmental Impact

Life Cycle Assessment

• Reduced fossil fuel consumption: 25-55% less than conventional plastics
• Lower greenhouse gas emissions: 15-60% reduction in carbon footprint
• Land use: Requires agricultural land for feedstock production
• Water usage: Varies depending on crop source and location

End-of-Life Scenarios

• Industrial Composting: Biodegrades in 60-180 days at 58°C
• Home Composting: Very slow degradation (years)
• Landfill: Minimal degradation due to lack of oxygen and proper conditions
• Mechanical Recycling: Possible but requires separate collection

Future Developments

Research Areas

• Improved heat resistance through molecular modifications
• Enhanced barrier properties for extended shelf life applications
• Cost reduction through improved production processes
• New feedstock sources including agricultural waste and algae

Market Trends

• Increasing demand from packaging industry
• Growing adoption in 3D printing applications
• Expansion into automotive and electronics sectors
• Development of home-compostable grades

Comparison with Other Bioplastics

Regulatory Status

Certifications

• ASTM D6400: Standard for compostable plastics
• EN 13432: European standard for packaging recoverable through composting
• FDA Approval: Food contact applications
• BPI Certification: Biodegradable Products Institute certification

Global Regulations

• Approved for food contact in US, EU, and many other regions
• Meets organic waste recycling standards in various countries
• Compliant with single-use plastic bans in many jurisdictions

Conclusion

PLA represents one of the most successful commercial bioplastics, offering a renewable and biodegradable alternative to conventional petroleum-based plastics. While it has limitations in terms of heat resistance and end-of-life processing requirements, ongoing research and development continue to improve its properties and expand its applications. As environmental concerns grow and technology advances, PLA is likely to play an increasingly important role in the transition to more sustainable plastic materials.

Last updated: August 2025