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From ancient times to modern times: the evolution of biodegradable polymers!
As the plastic pollution problem becomes increasingly serious, biodegradable polymers have gradually become the focus of global attention. These polymers can eventually be decomposed into environmentally friendly substances by the action of microorganisms, making them key to solving environmental problems. However, the development history of biodegradable polymers and their diverse applications does not end there. Today we will take you to explore the development and evolution of this special world.
History
Biodegradable polymers have a long history and have been utilized by humans since ancient times. One of the earliest biodegradable materials was "intestinal suture", commonly used in surgical procedures, and its use dates back to 100 BC. Intestinal sutures are made from sheep intestines. In modern times, they are mostly made of collagen purified from the intestines of cows, sheep or goats.
In 1992, many experts in the field of biodegradable polymers from around the world gathered together to discuss the definition and standards of this field.
With the advancement of science and technology, the concept of synthetic biodegradable plastics began to appear in the 1980s. Especially in 2012, Professor George Coates of Cornell University won the "President's Green Chemistry Challenge Award", further promoting the development of this field.
Structure and properties
The properties of biodegradable polymers are closely related to their structure, and typically these polymers are composed of ester, amide, or ether linkages. These polymers can be divided into two main categories: "agripolymers", such as polysaccharides from plants, and "biopolyesters", which are made from microorganisms or synthetic monomers.
Biodegradable polymers must be stable and durable, but easily degrade when disposed of.
In addition to structure, the water solubility and molecular weight of these polymers will affect their degradation rate, characteristics that are particularly important when applied to drug release and medical materials.
Synthesis
The synthesis of biodegradable polymers mainly relies on the synthesis of polyester, usually through direct condensation, ring-opening polymerization, etc. In particular, the use of ring-opening polymerization allows rapid and efficient production of polyesters, however continuous removal of by-product water is required to facilitate the reaction.
The use of metal catalysts has been approved as food additives, however there are still some concerns regarding biomedical uses.
In addition, in order to improve mechanical properties, many biopolymers are mixed or compounded with other polymers, which not only enhances strength but also improves processing properties.
Degradation mechanism
The degradation process of biodegradable polymers is usually divided into two categories: physical degradation and biological degradation. Physical degradation can include hydrolysis and photodegradation, while biological degradation can be subdivided into aerobic and anaerobic processes.
The ultimate goal of biodegradable polymers is to completely degrade into non-toxic gases, water and other inorganic salts.
In addition to the properties of the polymer itself, environmental factors such as pH, temperature, and types of microorganisms will also affect the degradation process.
Applications and uses
Biodegradable polymers have shown great potential in many fields such as medicine, agriculture and packaging, especially in drug delivery systems, which have attracted increasing attention. The biocompatibility and controlled degradation of these polymers make them ideal carriers for site-specific release of drugs.
For example, polylactic acid (PLA) and poly(lactic-co-glycolic acid) are widely used in the delivery of anticancer drugs.
As technology advances, these materials are also used in tissue engineering and regenerative medicine to support regeneration and repair of damaged tissues and organs.
In the field of packaging, biodegradable polymers such as PLA are gradually replacing traditional petroleum-derived materials to help reduce waste.
Future Outlook
As the scientific community becomes increasingly concerned about environmental issues, research and applications of biodegradable polymers will only continue to increase. However, facing its challenges in performance, safety and cost, can we find innovative solutions to truly achieve green development?
