In recent years, PLA is a very popular polymer material. PLA is biodegradable and can be used in direct contact with acidic, oily and other foods. PLA has higher hardness, higher tensile modulus and flexural modulus than traditional general-purpose resins, and it has good biocompatibility and biodegradability. The final products of degradation are water and carbon dioxide, and there is no secondary pollution, making it an alternative One of the most potential high polymers of traditional plastics. However, PLA itself also has some disadvantages, which limit its application range. Its flexibility is poor, and its impact strength, elongation at break and barrier properties are lower than those of commonly used resins.

It can be seen from the structure of PLA that the carbonyl group in the PLA molecular chain is coplanar with the adjacent oxygen atoms, and is very close to the adjacent carbon atoms, so it is not easy to rotate; therefore, the molecular chain flexibility is poor, the material is hard and brittle, and the impact resistance is poor. .

In addition, PLA is easy to degrade under the action of acid, alkali, alcohol and water when it melts, and has poor heat resistance. In order to better improve the flexibility of PLA and meet special packaging requirements, PLA needs to be modified to ensure safety and integrity during transportation and storage. Many experts at home and abroad have studied the modification of polylactic acid, and improved its flexibility and heat resistance by adjusting the raw material formula of PLA and modifying its film, thereby enhancing its competition with petroleum-derived plastic products. force.

Reinforced Modification of Polylactic Acid Film

The best way to enhance the modification is to add high-modulus fibers to the polymer matrix for composite modification to improve the shortcomings of low modulus and low strength of plastics. Natural plant fibers have the advantages of high specific strength, extensive resources, low cost, renewable and degradable, and are currently one of the most widely used fibers in polymer composites.

Toughening modification of polylactic acid film

Lactic acid is a glassy polymer with very low elongation at break (<10%), which greatly hinders its application in many fields. In recent years, the toughening modification of polylactic acid has become a hot spot of many researches. In order to improve the toughness of PLA, scholars have studied many methods, such as melt blending and crosslinking with plasticizers, bio-based tough polymers, thermoplastic elastomers, and inorganic fillers.

Citrate is a kind of green and environment-friendly plasticizer, which has been approved by the US Food and Drug Administration (FDA) as a food additive. The polar reaction between the ester group on the PLA chain and the citric acid ester makes the PLA and the citric acid ester have better compatibility, and effectively improves the brittleness of PLA by improving the mobility of the PLA chain segment.

Polyethylene glycol (PEG) is a non-toxic, water-soluble crystalline polymer. Low-molecular-weight PEGS has better compatibility with PLA, and can effectively reduce the glass transition temperature of PLA at a low concentration, greatly improving the The toughness and impact resistance of PLA.

Henan Techuang Biotechnology Co., Ltd. is a modern green and environmental protection enterprise integrating R&D, production, sales and technical services, providing services for biodegradable plastic bags and products. For more information, please visit the official website of Baydeebio: www.baydeebio.com