Recycled Filaments and Bio-Based Materials: The Future of Green Manufacturing

You have a water bottle in your hand. You drank its contents, threw the bottle in the recycling bin. A few weeks later, the same plastic is being used as filament in your 3D printer. Or crops harvested from a corn field are processed in a laboratory and become PLA filament. Even plastic waste floating in the ocean is collected and transformed into new 3D printing material.

This isn't science fiction - it's the reality of 2026. The 3D printing industry is taking serious steps toward sustainability. Recycled and bio-based materials are no longer niche products - they're becoming mainstream.

In this article, we'll explore the world of eco-friendly filaments.

Recycled PETG (rPETG): From Water Bottle to Filament

PET and PETG: Chemical Siblings

PET (Polyethylene Terephthalate):

• Water bottles, food containers
• Most recycled plastic worldwide

PETG (Glycol-modified PET):

• PET + Glycol → More durable, more flexible
• Ideal for 3D printing

Chemical similarity: PETG is modified PET. Same recycling processes can be applied.

rPETG Production Process

1. Collection

• Household PET bottles collected from recycling bins
• Sorting: Labels, caps removed

2. Washing and Cleaning

• Washing with detergent
• Removal of contaminants

3. Shredding

• Bottles separated into small particles (flakes)

4. Melting and Filtration

• Melted at 260-280°C
• Filters remove contaminant particles

5. Extrusion

• Melt becomes 1.75mm or 2.85mm diameter filament
• Diameter tolerance controlled (±0.03 mm)

6. Packaging

• Stored in moisture-proof vacuum bags

rPETG Advantages

Environmental:

• 50-70% less CO₂ emissions than virgin PETG
• Plastic waste reduction
• Contribution to circular economy

Technical:

• Nearly same properties as virgin PETG
• Strength: 5-10% lower (usually unnoticeable)
• Print settings: Same

Economic:

• Price: Competitive with virgin (sometimes cheaper)

Brands and Products

Refil (Netherlands):

• From 100% recycled PET bottles
• Transparent and colored options
• Price: €20-25/kg

Reflow (USA):

• From locally collected PET waste
• "From bottle to spool in 200 miles"
• Carbon footprint: 60% lower than virgin

Filamentive (UK):

• rPET and rPLA
• Carbon neutral shipping

rPETG Printing Tips

Settings:

• Nozzle: 230-250°C
• Bed: 70-80°C
• Speed: 40-60 mm/s

Differences:

• Can be slightly more brittle (retraction setting important)
• Moisture absorption: Slightly more than virgin (drying recommended)

Recycled PLA (rPLA): Second Life

rPLA Challenges

Problem: PLA recycling is harder than PETG.

Reasons:

1. Moisture sensitivity: PLA absorbs a lot of moisture, drying difficult
2. Low melting temperature: Risk of degradation during melting process
3. Crystallization: Can be more brittle after recycling

Result: rPLA not as common as rPETG.

rPLA Sources

Industrial Waste:

• Failed prints from 3D printing factories
• Clean, uniform → Easier recycling

Post-consumer:

• Household PLA prints
• Mixed colors, contamination → Difficult

Current Solution: Most rPLA is produced from industrial waste.

PLA's Biological Origin: From Corn Field to Printer

What Is PLA?

Polylactic Acid:

• Polymer of lactic acid
• Bio-based, doesn't use petroleum

PLA Production: Step by Step

1. Agriculture

• Corn, sugar cane or sugar beet grown
• Contains starch

2. Starch Extraction

• Starch isolated from plants

3. Fermentation

• Starch → Glucose (sugar)
• Bacteria (Lactobacillus) convert glucose to lactic acid
• Just like making yogurt!

4. Polymerization

• Lactic acid molecules chain together
• PLA polymer forms

5. Pellet Production

• PLA packaged as small pellets

6. Filament Extrusion

• Pellets melted, made into filament

Is PLA Environmentally Friendly?

Pros:

• Renewable resource: Plant, not petroleum
• Lower CO₂: 50% less than virgin ABS
• Biodegradable (in theory): Industrial compost

Cons:

• Food competition: Corn can be used for food (ethical debate)
• Agricultural impact: Pesticides, water use, land change
• Industrial compost required: Doesn't degrade at home

Next-Gen PLA: Non-food Feedstock

Problem: Food-sourced PLA creates ethical issues.

Solution: PLA from non-food sources

Examples:

1. Agricultural waste: Corn stalks, wheat straw
2. Algae: Fast growing, doesn't require farmland
3. CO₂ capture: Lactic acid production from atmospheric CO₂ (experimental)

Companies:

• NatureWorks: PLA from corn (largest producer)
• Total Corbion: PLA from sugar cane
• Newlight: Air-based carbon capture (AirCarbon)

Ocean Plastic: Production While Cleaning the Ocean

Problem: Plastic Pollution

Statistics:

• 8-12 million tons of plastic enter the ocean annually
• By 2050, there will be more plastic than fish in oceans (by weight)

3D Printing's Contribution: Ocean plastic filaments

Ocean Plastic Filament Production

1. Collection

• Beach cleanup, ocean collector ships
• Mostly PET bottles, HDPE caps

2. Sorting

• Separated by plastic types
• Salt, sand, biological waste cleaned

3. Recycling

• Standard recycling process (washing, shredding, melting)

4. Filament

• rPETG or mixed formulation

Ocean Plastic Brands

Oceanplast3D:

• Plastics collected from Norwegian coasts
• Each spool cleans 50+ bottles from ocean
• Certification: Ocean Bound Plastic (OBP)

Fishy Filaments (UK):

• Fishing nets + marine waste
• Color: Usually blue-green tones (natural source)

3devo (Ocean Filament):

• From Dutch coasts
• Mixed color (blue-gray mixture)

Impact and Realism

Positive:

• Contribution to ocean cleanup
• Awareness raising

Realism:

• Ocean plastic filaments constitute less than 0.001% of total waste
• Real solution: Reduction at source (single-use plastic ban)

Conclusion: High symbolic value, but not the main solution.

Compostable Filaments: Plastic That Disappears in Soil

PLA: Industrial Compost

Requirements:

• Temperature: 55-60°C (constant)
• Humidity: 50-60%
• Microorganisms: Special bacteria
• Time: 6-12 months

Current situation: Very few industrial compost facilities exist (almost none in Turkey).

PHA: True Biodegradable

Polyhydroxyalkanoates (PHA):

• Natural polymer produced by bacteria
• Truly biodegradable: Home compost, ocean, soil - degrades everywhere
• Time: 3-6 months (home compost)

Disadvantages:

• Very expensive (3-5 times PLA)
• Difficult printing (brittle)
• Rare

Brands:

• Kanesis: PHA filament
• Danimer Scientific: Nodax PHA

Lignin-Based Filaments

Lignin: Natural polymer found in tree and plant cell walls

Properties:

• Obtained from waste product (byproduct of paper production)
• Truly biodegradable
• Mixed with PLA (30-50% lignin)

Brands:

• Fiberlogy Easy Wood: PLA + lignin
• ColorFabb WoodFill: PLA + wood fiber + lignin

Situation in Turkey: Slow But Progressing

Current Products

Recycled:

• A few local producers in trial stage
• Import: Brands like Refil, Reflow available online

Bio-based:

• PLA common (NatureWorks Ingeo import)
• PHA, lignin-based: Not yet available

Awareness and Demand

Status:

• Hobbyists: Low awareness (less than 10% using "green" filament)
• Companies: Early stage, some mention in sustainability reports

Barriers:

• Price: rPETG/rPLA 10-30% more expensive than virgin (import cost)
• Knowledge gap: "Virgin is higher quality" perception

Potential: PET Recycling

Turkey Statistics:

• Annual PET bottle consumption: 4-5 billion units
• Recycling rate: 50-60%
• Potential: Very large raw material source

Opportunity: Local rPETG producers can be established.

Conclusion: Green Production, No Longer an Option, a Necessity

Recycled and bio-based filaments are making 3D printing more sustainable. Each rPETG spool is a small but meaningful step against plastic pollution.

What You Can Do as a Consumer:

1. Choose recycled: rPETG, rPLA
2. Collect failed prints: Save for recycling
3. Biodegradable projects: Use PHA for short-lived products
4. Awareness: Share in community

Future: By 2030, virgin filaments will be the exception - recycled and bio-based will be the norm.

In our next article, we'll look at the future of 3D printing: AI, nanotechnology, 4D printing and more.