【Frontiers in HaiChuan Chemical Technology】A team from Donghua University has successfully developed biodegradable melt-blown nanofiber materials

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Against the backdrop of the growing global emphasis on environmental protection, the non-degradability of traditional petrochemical plastics imposes a heavy burden on the environment. According to research projections, by 2025, 11 billion tons of plastic will be discarded directly into the natural environment. Petrochemical plastics, due to their strong covalent bonds, generally have poor natural degradation properties; the incomplete decomposition products, namely microplastics, continue to accumulate in the soil, causing long-term and severe environmental pollution. Therefore, developing biodegradable alternative materials has become an important task for researchers. A research paper titled “Large-Scale Preparation of Mechanically High-Performance and Biodegradable PLA/PHBV Melt-Blown Nonwovens with Nanofibers”, published in the Chinese Academy of Engineering’s journal Engineering, by researchers from Donghua University and Qingdao University, brings us new hope. Liu Gaohui from Donghua University is the first author, while Researcher Wang Xianfeng and Professor Ding Bin are the corresponding authors. The article reports a simple method for the large-scale production of high-mechanical-property, biodegradable PLA/PHBV melt-spun fiber materials. As a biodegradable material, PLA is widely used in fields such as medicine, pharmaceuticals, agriculture, packaging, and clothing due to its good biocompatibility and renewability. However, PLA melt-blown fiber materials generally suffer from low strength and poor toughness, which limits their use in applications that require high performance. To address this issue, researchers added a small amount of PHBV to PLA, and experiments showed that this addition could increase the crystallization rate and degree of crystallinity of the material. During the experiment, the researchers dried PLA and PHBV in a forced-air oven at 80°C for 12 hours to remove moisture. Then, PHBV masterbatches were mixed uniformly with PLA masterbatches in mass fractions of 0%, 2.5%, 5.0%, and 7.5%, respectively. Finally, samples were fabricated using melt-blowing equipment. The experimental results showed that as the PHBV content increased from 0 to 7.5 wt%, the diameter of PLA/PHBV melt-blown fibers decreased significantly, and the proportion of nanofibers increased from 7.7% to 42.9%. In particular, when the PHBV content was 5 wt%, the resulting PLA/PHBV melt-blown fiber material exhibited high mechanical properties, with tensile stress, elongation, and toughness reaching 2.5 MPa, 45%, and 1.0 MJ/m³, respectively. This result indicates that the addition of an appropriate amount of PHBV can significantly improve the mechanical properties of PLA melt-blown fiber materials, enabling them to meet the requirements of various high-performance applications. What’s even more encouraging is that this PLA/PHBV melt-blown fiber material also possesses good biodegradability. The researchers cut the PP (polypropylene), PLA, and PLA/PHBV melt-blown fiber materials into 10 cm × 10 cm pieces, buried them in soil at a depth of 10 cm, and added 10% efficient microbial composting bacteria to accelerate biodegradation. Experiments showed that PLA and PLA/PHBV melt-blown fiber materials began to break down after being buried in soil for 2 months, and could be completely degraded into carbon dioxide and water after 4 months, whereas the PP melt-blown fiber materials showed no significant changes. This indicates that PLA/PHBV melt-blown fiber materials can degrade naturally at the end of their useful life, causing no long-term pollution to the environment, making them an environmentally friendly material. In addition, the researchers also characterized and analyzed the stretching process of PLA/PHBV melt-blown fiber materials, and proposed a general stretching failure model for such fiber materials. The development of this model provides a theoretical basis for further improving the mechanical properties of non-woven materials, and helps to promote the application and development of biodegradable materials in more fields. This study provides a new method for the large-scale production of biodegradable PLA/PHBV melt-blown fiber materials with high strength and excellent toughness. By adding a small amount of PHBV to PLA, not only was the crystallization rate and degree of the material increased, thereby improving its mechanical properties, but its good biodegradability was also maintained. This material is expected to replace the existing PP melt-blown fiber materials, and it holds broad application prospects in fields such as medicine, filtration, and environmental protection. With the continuous development and improvement of related technologies, biodegradable materials will play an increasingly important role in environmental protection and sustainable development.