Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico.
Departamento de Ingeniería Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico.
Sci Total Environ. 2024 Dec 10;955:176763. doi: 10.1016/j.scitotenv.2024.176763. Epub 2024 Oct 10.
Evaluating compostability is increasingly essential for proving commercial bio-based cutlery or packaging since these materials must biodegrade under controlled conditions quickly. Utensils for eating represent Mexico's most popular consumer single-use materials, and Mexican regulations based on biodegradation or compostability are still vague and lack scientific evaluations. This study analyzed three bio-based polymeric materials (bags, dishes, and forks) from commercial brands following Mexican regulations and using various analytical techniques to verify their biodegradability and compostability. First, weight loss measurements, stress-strain tests, and topographic imaging were applied for preliminary observations at the macro scale up to 90 days of compostability. Besides, spectroscopy, microscopy, and thermal techniques indicate changes and behavior of the bio-based materials depending on the composition. The results suggest that bags exhibited the highest decomposition rate (80 %) compared to dishes and forks. Similarly, mechanical resistance indicates a reduction of 62 % for bags, 30 % for dishes, and almost none for forks. Texture image analysis revealed that the complexity and roughness of the materials increased over time, correlating with the physical changes observed. These results indicate minimal surface topography changes and higher stiffness for dishes and forks, indicating low biodegradability. SEM images supported these findings, showing surface degradation in bags and dishes but not in forks. FTIR and XRD analyses confirmed the presence of polyamide (bags) and polypropylene (dishes and forks). These results reduce biodegradation and differ from the claims made by manufacturers. The thermal analysis found similar results, indicating that the materials' thermal stability decreased after degradation, which is related to lower biodegradability and compostability. Overall, the study concluded only bags meet the criteria for compostability in national regulations. However, dishes and forks made of petroleum-derived polymers have higher resistance to natural and microbial degradation.
评估堆肥能力对于证明商业生物基餐具或包装的可堆肥性变得越来越重要，因为这些材料必须在受控条件下快速生物降解。餐具是墨西哥最受欢迎的消费一次性材料，而基于生物降解或堆肥能力的墨西哥法规仍然模糊不清，缺乏科学评估。本研究分析了三种商业品牌的生物基聚合材料（袋子、盘子和叉子），这些材料符合墨西哥法规，并使用各种分析技术来验证其生物降解性和可堆肥性。首先，进行了重量损失测量、应力-应变测试和形貌成像，以在宏观尺度上对 90 天的可堆肥性进行初步观察。此外，光谱、显微镜和热技术表明，生物基材料的组成会发生变化，并表现出不同的行为。结果表明，与盘子和叉子相比，袋子的分解率最高（80%）。同样，机械阻力表明袋子的减少了 62%，盘子的减少了 30%，叉子的几乎没有减少。纹理图像分析表明，随着时间的推移，材料的复杂性和粗糙度增加，与观察到的物理变化相关。这些结果表明盘子和叉子的表面形貌变化最小，刚性较高，生物降解性较低。SEM 图像支持了这些发现，显示袋子和盘子的表面降解，但叉子没有。FTIR 和 XRD 分析证实了袋子中存在聚酰胺，盘子和叉子中存在聚丙烯。这些结果降低了生物降解性，与制造商的说法不同。热分析得出了相似的结果，表明材料的热稳定性在降解后降低，这与较低的生物降解性和可堆肥性有关。总的来说，研究结果表明只有袋子符合国家法规的可堆肥性标准。然而，由石油衍生聚合物制成的盘子和叉子具有更高的抗自然和微生物降解能力。
