Table 1.
Key aspects of different bio-based plastics and end-of-life (EoL) in terms of LCA.
| Bio-based plastic | Type | Characteristics | Conversion pathways | Applications | Price (€ kg−1) | Environmental impact | EoL options | References |
|---|---|---|---|---|---|---|---|---|
| Polylactic acid (PLA) | Bio-based/biodegradable plastic | • Density: 1.24 g cm−³ | PLA is produced from the fermentation of plant-derived carbohydrates by different bacterial species. The glucose produced is converted to lactic acid. Lactic acid is polymerized to low molecular weight PLA, which is subsequently depolymerized to yield lactide and then high molecular weight PLA | • Agriculture | 2.0 | • PLA's carbon uptake is considered only for biopolymers, which is their advantage in terms of environmental aspects compared to fossil-based plastics | • Biodegradable | [11,[60], [61], [62], [63]] |
| • Tensile strength: 50 MPa | • Tissue engineering | • Due to natural conversion, PLA emits 2.8 kg CO2 kg−1 during its life cycle. | • Compostable | |||||
| • Flexural strength: 80 MPa | • Biomedicine | • PLA saves ∼66% of the energy required to produce conventional plastics | • Recycling | |||||
| • Impact strength: 96.1 J m−1 | • 3D printing | • Landfill | ||||||
| • Shrink rate: 0.37–0.41% | • Incineration | |||||||
| Polybutylene succinate (PBS) | Bio-based/biodegradable plastic | • Thermoplastic with melting point of about 90–120 °C | PBS is produced from the hydrolysis of non-edible lignocellulosic biomass. The polymerization process is initiated by the reaction of 1,4-butanediol and succinic acid produced by various microbial strains to generate PBS oligomers. | • Biomedicine | 4.0 | • Non-edible lignocellulosic biomass and food wastes in the production can decrease PBS environmental impact | • Biodegradable | [[64], [65], [66], [67], [68]] |
| • Glass transition temp. of about −45 to −10 °C | • Hygiene products | • GHG emissions from PBS are ∼5.88 kg CO2-eq kg−1 | • Compostable | |||||
| • Biodegradable bags | • Recycling | |||||||
| • Mulch film | • Landfill | |||||||
| • Incineration | ||||||||
| Cellulose acetate (CA) | Bio-based/biodegradable plastic | • Density: 1.28 g cm−3 | CA is derived from cellulose through acetylation of some of the hydroxyl groups | • Textile industries | 5.0 | • The CA green synthesis pathway has lower environmental consequences and is a more sustainable route when compared to the conventional processing method. | • Biodegradable | [[69], [70], [71], [72]] |
| • Tensile strength: 30 MPa | • Plastic films | • CA can be biodegraded or hydrolyzed after consumption into cellulose and acetic acid in the natural environment. These compounds return to the environment with no adverse effects. | • Compostable | |||||
| • Water absorption: 2.2% | • Photography films | • Recycling | ||||||
| • Heat deflection temp.: 60–63 °C | • Packaging | • Landfill | ||||||
| • Melting temp.: 170–240 °C | • Separating membranes | |||||||
| • Cigarette filter | ||||||||
| • Biomedical porous beads | ||||||||
| • Based on the LCC and S-LCA, CA-derived products are significant materials | ||||||||
| Starch-based polymers (SBPs) | Bio-based/biodegradable plastic | Variable depending on the type of starch and blends used | SBPs are materials derived from granular native starch by extrusion with the addition of plasticizer agents | • Textile | 2.0–4.0 | • Starch utilization in bioplastics production causes a reduction in GHG emissions (>80%) and fossil fuel consumption (>60%) | • Biodegradable | [[73], [74], [75]] |
| • Packaging | • When compared to synthetic plastics, starch might cause an increase in eutrophication potential and land usage | • Compostable | ||||||
| • Pharmaceutical | • SBPs have better environmental profiles than PE in all categories evaluated | • Landfill | ||||||
| • Biomedicine | ||||||||
| Bio-based polyethylene terephthalate (Bio-PET) | Bio-based/non-biodegradable plastic | • Density: 1.38 g cm−3 | • Produced from first-generation ethanol, which is oxidized to produce ethylene oxide, which is then converted to Bio-PET | • Durable bottles | 1.2 | • Bio-PET plastic is highly resistant to biodegradation because of its high aromatic content, which also promotes its accumulation in the environment | • Biodegradable by few strains such as Ideonella sakaiensis 201-F6 | [[76], [77], [78]] |
| • Melting point: 250–260 °C | • The second pathway is the fermentation of sugar into isobutanol, which is involved in the Gevo process to generate terephthalic acid, which is polycondensed to generate Bio-PET | • Packaging | • Compostable | |||||
| • Boiling point: ∼350 °C | • Textile manufacturing | • Recycling | ||||||
| • Thermal conductivity: 0.15–0.24 W m−1 K−1 | • Medicine | • Landfill | ||||||
| • Refractive index: 1.57–1.58 | • Incineration | |||||||
| Bio-polyethylene (Bio-PE) | Bio-based/non-biodegradable plastic | • Specific gravity: 0.941–0.965 g cm−3 | Produced from first-generation ethanol, which is catalytically dehydrated to generate ethylene and polymerized to yield Bio-PE | • Toy manufacturing | 2.3 | • The manufacture of bio-ethylene would not be cost-competitive with ethylene obtained from petrochemicals | • Biodegradable | [39,[79], [80], [81]] |
| • Tensile strength: 3100–5500 psi | • Cosmetics | • Bio-PE leads to GHG emissions that are around −0.75 kg CO2-eq per kg polyethylene, which is 140% lower than the production of petrochemical PE; the savings on the use of non-renewable energy are approximately 65% | • Compostable | |||||
| • Elongation: 20–1000% | • Personal care | • One kilogram of bio-PE costs around 30% more than 1 kg of fossil-based PE | • Recycling | |||||
| • Tensile modulus: 0.6–1.8 | • Food packaging | • Landfill | ||||||
| • Heat deflection temp.: 110–130 °C | • Incineration |