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Changchun Institute of Applied Chemistry, Chinese Academy of Sciences: Stereocomplex PLA Melt-Blown Nonwoven with High Stability
Biodegradable and Recyclable Center 2025-03-04 09:19:57
Article Background

Polylactic acid (PLA) is a polyester polymer with lactic acid as the repeating unit, featuring excellent biodegradability. When discarded after use, it can degrade into water and carbon dioxide without causing environmental pollution. As a biodegradable and environmentally friendly polymer, PLA has broad applications in contemporary society, such as substituting for some traditional polymers in fiber materials. However, its limited stability and lower melting point restrict its usage in heat-resistant and durable application scenarios.

Article Background
Article Background
Article Background
Article Background
Article Background

Polylactic acid (PLA) is a polyester polymer with lactic acid as the repeating unit, featuring excellent biodegradability. When discarded after use, it can degrade into water and carbon dioxide without causing environmental pollution. As a biodegradable and environmentally friendly polymer, PLA has broad applications in contemporary society, such as substituting for some traditional polymers in fiber materials. However, its limited stability and lower melting point restrict its usage in heat-resistant and durable application scenarios.

Poly(lactic acid) (PLA) is a polyester polymer with lactic acid as the repeating unit, featuring good biodegradability. When discarded after use, it can degrade into water and carbon dioxide without causing environmental pollution. As a biodegradable and environmentally friendly polymer, PLA is widely used in contemporary society, such as replacing some traditional polymers in the field of fiber materials. However, its limited stability and low melting point restrict its application in heat-resistant and durable scenarios.

Poly(lactic acid) (PLA) is a polyester polymer with lactic acid as the repeating unit, featuring good biodegradability. When discarded after use, it can degrade into water and carbon dioxide without causing environmental pollution. As a biodegradable and environmentally friendly polymer, PLA is widely used in contemporary society, such as replacing some traditional polymers in the field of fiber materials. However, its limited stability and low melting point restrict its application in heat-resistant and durable scenarios.

Article Overview
Article Overview
Article Overview
Article Overview
Article Overview
Based on the above background, recently, the research group led by Professor Hui Liang Zhang from Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, prepared stereocomplex crystalline modified PLA melt-blown nonwovens (Figure 1) using a melt blending method of poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA). Through hydrogen bonding, stereocomplex crystals (Figure 2) were formed to improve the stability of the PLA melt-blown nonwovens. The structure, thermal properties, thermal stability, biodegradability, and crystalline morphology were studied in detail. With the increase in PDLA content, more stereocomplex crystals were generated, and the WAXD diffraction peaks of the stereocomplex crystals gradually intensified (Figure 3).
Based on the above background, recently, a research group led by Professor Zhang Huiliang from the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, used a method of melt blending left-handed polylactic acid (PLLA) with right-handed polylactic acid (PDLA) to prepare stereocomplex crystal modified polylactic acid melt-blown nonwoven fabric (Figure 1). Through the action of hydrogen bonds, stereocomplex crystals (Figure 2) are formed to improve the stability of the polylactic acid melt-blown nonwoven fabric. The structure, thermal properties, thermal stability, biodegradability, and crystalline morphology were studied in detail. As the content of PDLA increases, more stereocomplex crystals are generated, and the WAXD diffraction peaks of the stereocomplex crystals gradually strengthen (Figure 3).
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Figure 1 Melt-blown nonwoven fabric manufacturing process.
Figure 1 Melt-blown nonwoven fabric manufacturing process.
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Figure 2 Schematic diagram of stereocomplex crystal formation.

Figure 2 Schematic diagram of stereocomplex crystal formation.
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Figure 3 WAXD diffraction pattern of melt-blown nonwoven fabric.

Figure 3 WAXD diffraction pattern of melt-blown nonwoven fabric.
As the content of stereocomplex crystals increases, as shown in Figure 4, the storage modulus (G'), loss modulus (G''), and complex viscosity (|η*|) of the PLLA/PDLA blend increase. In terms of rheological properties, when the PDLA content is 0 wt% to 3 wt%, due to the low content of stereocomplex crystals, the system viscosity remains almost unchanged, exhibiting Newtonian fluid behavior; after exceeding 3 wt%, non-Newtonian behavior becomes more pronounced.
As the content of stereocomplex crystals increases, as shown in Figure 4, the storage modulus (G'), loss modulus (G''), and complex viscosity (|η*|) of the PLLA/PDLA blend increase. In terms of rheological properties, when the PDLA content is 0 wt% to 3 wt%, due to the low content of stereocomplex crystals, the system viscosity remains almost unchanged, exhibiting Newtonian fluid behavior; after exceeding 3 wt%, non-Newtonian behavior becomes more pronounced.
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Figure 4 (a) Storage modulus (G'), (b) loss modulus (G''), and (c) complex viscosity (|η*|) of the PLLA/PDLA blend.

The results of thermogravimetric analysis (Figure 5) show that the thermal stability of the PLLA/PDLA melt-blown nonwoven fabric is significantly enhanced compared to pure PLLA melt-blown nonwoven fabric. When the PDLA content reaches 10 wt%, the 10% weight loss temperature (T10%) increases from 277.5 ℃ to 342.4 ℃, and the maximum decomposition rate temperature rises from 324.7 ℃ to 376.8 ℃. This is attributed to the formation of stereocomplex crystals, which strengthen intermolecular interactions and improve the thermal stability of the material.
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Figure 5 Thermogravimetric curves of polylactic acid melt-blown nonwoven fabric.

Figure 5 Thermal weight loss curve of polylactic acid meltblown nonwoven fabric.
The biodegradability, as shown in Figure 6, indicates that the weight loss rate of PLLA/PDLA meltblown nonwoven fabric decreases with the increase of PDLA content, but the overall degradation rate still remains at a high level. Stereocomplex crystals have stronger resistance to protease K compared to pure PLLA. During enzymatic degradation, protease K preferentially degrades the amorphous regions, while the stable stereocomplex crystals act as a crystalline framework, enhancing the material's resistance to enzymatic degradation.
The biodegradability, as shown in Figure 6, indicates that the weight loss rate of PLLA/PDLA meltblown nonwoven fabric decreases with the increase of PDLA content, but the overall degradation rate still remains at a high level. Stereocomplex crystals have stronger resistance to protease K compared to pure PLLA. During enzymatic degradation, protease K preferentially degrades the amorphous regions, while the stable stereocomplex crystals act as a crystalline framework, enhancing the material's resistance to enzymatic degradation.
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Figure 6 Enzymatic degradation weight loss curve of polylactic acid meltblown nonwoven fabric over time.

Figure 6 Enzymatic degradation weight loss curve of polylactic acid meltblown nonwoven fabric over time.
Article Conclusion
Article Conclusion
Article Conclusion
Article Conclusion
Article Conclusion

This study provides an effective strategy for obtaining and large-scale preparation of high-performance polylactic acid meltblown nonwoven fabric. The prepared environmentally friendly polylactic acid meltblown nonwoven fabric exhibits excellent thermal stability and resistance to degradation, promising to expand the application of PLA materials in areas such as packaging, filtration, and medical fields. In the future, the research team will further explore methods to optimize material performance, promote the wider application of PLA materials across more industries, and contribute to sustainable development.

This study provides an effective strategy for obtaining and large-scale preparation of high-performance polylactic acid meltblown nonwoven fabric. The prepared environmentally friendly polylactic acid meltblown nonwoven fabric exhibits excellent thermal stability and resistance to degradation, promising to expand the application of PLA materials in areas such as packaging, filtration, and medical fields. In the future, the research team will further explore methods to optimize material performance, promote the wider application of PLA materials across more industries, and contribute to sustainable development.

 

 

 

 

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