Talc - the most commonly used inorganic nucleating agent for polylactic acid

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　　Polylactic acid is a kind of polymer obtained by extracting and chemical polymerization with renewable resources as raw materials, which is biodegradable and biocompatible, and can be completely decomposed into carbon dioxide and water after 3 to 6 months under composting conditions. The use and promotion of polylactic acid can reduce the consumption of petroleum resources, and play a role in energy conservation and emission reduction, which is of great significance for environmental protection.

　　

　　Polylactic acid has high strength, high modulus, as well as good transparency and air permeability, but its crystallization rate is too slow during processing, resulting in a prolonged processing cycle, heat resistance is very poor, greatly limiting the application field of polylactic acid products.

　　At present, the most common way to improve the performance of polylactic acid is to add a nucleation agent, and in the actual enterprise processing application, talc is the most commonly used inorganic nucleating agent of polylactic acid, which can improve the mechanical properties of polylactic acid such as stretching and bending, and improve its heat resistance.

　　Wang Yanning et al. studied the effects of different content talcum powder on the crystallization performance and comprehensive mechanical properties of high-gloss pure polylactic acid, and the results showed that the crystallization peak temperature of polylactic acid increased with the increase of talc content, and the crystalline temperature zone continued to move in the direction of high temperature, and the crystallization rate also accelerated.

　　Compared with pure polylactic acid, when the mass fraction of talc is 10%, the comprehensive mechanical properties of polylactic acid reach the maximum, and its crystal peak temperature is increased by 13.7K, the tensile strength is increased from 58.6MPa to 72.0MPa, the tensile strain at break is increased from 2.7% to 4.6%, the bending strength is increased from 88.9MPa to 104.0MPa, and the bending modulus is increased from 3589MPa to 4837MPa. At the same time, the addition of talc will not change the crystal form of polylactic acid, but will make the size of polylactic acid spheroids significantly smaller and the crystal nucleus density increase significantly.

　　Source: Wang Yanning, Jin Jiangbin. The effect of talcum powder on polylactic acid[J].Shanghai Plastics, 2019(04):16-21", edited by [Powder Technology Network], please indicate the source!