Degradable resources: from lactic acid to polylactic acid

Degradable resources: from lactic acid to polylactic acid

with the increasing global attention to environmental protection, the development and application of degradable resources has become a hot topic in the chemical industry. Among them, lactic acid and its derived material polylactic acid (PLA) have gradually become the focus of research and application because of its excellent biodegradability and renewability. In this paper, the potential and prospect of this biodegradable resource will be discussed in detail from three aspects: the source of lactic acid, the synthesis of polylactic acid and its application.

Lactic Acid Source and Preparation

Lactic acid, as an important organic compound, widely exists in nature. Its main sources include plant base and microbial fermentation. Plant-based lactic acid is mainly produced by the fermentation of carbohydrates such as starch and cellulose, while microbial fermentation is produced by the metabolism of glucose by microorganisms such as lactic acid bacteria. Compared with traditional petrochemical resources, the preparation process of lactic acid is more environmentally friendly, and the raw materials are renewable, which meets the requirements of sustainable development.

In recent years, with the progress of biotechnology, the production efficiency and purity of lactic acid have been significantly improved. For example, the production of lactic acid can be improved by optimizing the metabolic pathways of lactic acid bacteria through genetic engineering techniques. The use of agricultural wastes such as straw and cassava dregs as fermentation raw materials not only reduces production costs, but also realizes the recycling of resources. These technological innovations laid the foundation for large-scale production of lactic acid.

Synthesis and Properties of Polylactic Acid

Polylactic acid is a bio-based degradable plastic made from lactic acid by polymerization. The synthesis process mainly includes polycondensation reaction and ring opening polymerization method. The polycondensation reaction is the esterification of hydroxyl and carboxyl groups in the lactic acid molecule to form a long-chain polymer. The ring-opening polymerization law uses the ring structure of lactic acid to open the ring structure under the action of a catalyst to generate a linear polymer. Compared with traditional petrochemical plastics, polylactic acid has good biodegradability, compostability and low toxicity, and is an ideal environmental protection material.

The performance characteristics of polylactic acid make it have a wide range of applications in many fields. For example, its mechanical properties are close to those of traditional plastics, and it can be degraded into carbon dioxide and water in the natural environment without causing long-term pollution to the environment. Polylactic acid also has good biocompatibility and can be used in medical fields, such as degradable sutures and drug release materials. These characteristics make polylactic acid show a broad market prospect in packaging, textile, medical and other fields.

Polylactic Acid Applications and Challenges

The application of polylactic acid is mainly concentrated in the fields of packaging, textile and medical treatment. In the field of packaging, polylactic acid can be used to make degradable films, disposable tableware, etc., to replace traditional plastics and reduce white pollution. In the textile field, polylactic acid fiber has good air permeability and comfort, and can be used to make clothing, home textile products and so on. In the medical field, the biodegradability of polylactic acid makes it an ideal choice for surgical sutures, bone nails and other medical materials.

The application of polylactic acid also faces some challenges. Its production cost is high, mainly because the preparation and polymerization process of lactic acid requires high technical investment and energy consumption. The mechanical properties and thermal stability of polylactic acid still need to be further improved to meet the needs of high-end applications. The recycling and management of polylactic acid waste is also an urgent problem to be solved. Although polylactic acid itself can be degraded, its degradation conditions are harsh and require a specific composting environment, which may cause inconvenience in practical applications.

Future Outlook

In general, polylactic acid, as a typical degradable resource, has important environmental significance and application value. With the continuous advancement of technology and the gradual reduction of costs, polylactic acid is expected to replace traditional petrochemical materials in more fields and promote sustainable development. In the future, the chemical industry should further strengthen technological innovation, optimize the production process of polylactic acid, and improve its performance and economy. The government and society should also increase policy support and promotion of degradable materials to jointly promote the development of environmental protection.

Conclusion

the theme of "Degradable resources: from lactic acid to polylactic acid" not only reflects the technological innovation of the chemical industry, but also highlights the responsibility for environmental protection. Through in-depth research on the source of lactic acid, the synthesis of polylactic acid and its application, we are expected to develop more environmentally friendly materials and contribute to the construction of a green and sustainable future.