| Disposal Environment | Visual Appearance after 24 Months | Total Degradation Weight Loss Rate | Residual Substances | Pollution Risk |
|---|---|---|---|---|
| Industrial Compost | Fully vanished, no fragments at all | >99% | Only humus, CO₂ and water, zero plastic residue | No risk |
| Well-managed Home Compost | No intact sheet, no visible fragments | 92%–98% | Trace organic particles, no persistent plastic pellets | Extremely low risk |
| Rough Open-air Home Compost | No intact sheet, only tiny thin fragments | 70%–85% | Small fine PBAT microparticles | Slight short-term soil pollution |
| Buried in Natural Soil | No whole sheet left, only minor fine residues | 65%–85% | Tiny broken PBAT scraps | Temporary trace particles, no long-term accumulation |
| Immersed in Coastal Seawater | Severely perforated sheet, only thin broken skeletons remain | 45%–60% | Fragile thin PBAT film scraps | Moderate marine pollution, fully degraded within 5 years |
Core difference between corn starch sheet and PLA sheet
Lower degradation threshold: Starch does not require a high temperature of 55 ℃, and can be degraded by soil and seawater at room temperature. No intact large areas will be retained in any environment for 24 months; PLA can only be effectively decomposed by industrial compost, and the soil and seawater are basically intact after 2 years;
The performance of industrial composting remains the same: both can completely mineralize 100% within 2 years;
The advantages of natural/marine environment are obvious: in the wild and into the sea scenarios, the degradation rate of corn starch based materials is 3-4 times that of PLA;
Shortcoming: Pure starch has no formability, and the starch sheets on the market are compounded with PBAT polyester, resulting in a small amount of residual polyester fragments. The complete mineralization period is longer than that of pure starch raw materials.