Tertyshnaya Yulia V, Podzorova Maria V, Khramkova Anastasia V, Ovchinnikov Vasily A, Krivandin Aleksey V
Department of Biological and Chemical Physics of Polymers, Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygina Str., Moscow 119334, Russia.
Department of Chemistry of Innovative Materials and Technologies, Plekhanov Russian University of Economics, 36 Stremyanny per., Moscow 117997, Russia.
Polymers (Basel). 2023 Apr 19;15(8):1930. doi: 10.3390/polym15081930.
In the work, the impact of the biological medium and water on structural rearrangements in pure polylactide and polylactide/natural rubber film composites was studied. Polylactide/natural rubber films with a rubber content of 5, 10, and 15 wt.% were obtained by the solution method. Biotic degradation was carried out according to the Sturm method at a temperature of 22 ± 2 °C. Hydrolytic degradation was studied at the same temperature in distilled water. The structural characteristics were controlled by thermophysical, optical, spectral, and diffraction methods. Optical microscopy revealed the surface erosion of all samples after exposure to microbiota and water. Differential scanning calorimetry showed a decrease in the degree of crystallinity of polylactide by 2-4% after the Sturm test, and a tendency to an increase in the degree of crystallinity after the action of water was noted. Changes in the chemical structure were shown in the spectra recorded by infrared spectroscopy. Due to degradation, significant changes in the intensities of the bands in the regions of 3500-2900 and 1700-1500 cm were shown. The X-ray diffraction method established differences in diffraction patterns in very defective and less damaged regions of polylactide composites. It was determined that pure polylactide hydrolyzed more readily under the action of distilled water than polylactide/natural rubber composites. Film composites were more rapidly subjected to biotic degradation. The degree of biodegradation of polylactide/natural rubber composites increased with the rise in the content of natural rubber in the compositions.
在这项工作中，研究了生物介质和水对纯聚乳酸及聚乳酸/天然橡胶薄膜复合材料结构重排的影响。通过溶液法制备了橡胶含量为5%、10%和15%（重量）的聚乳酸/天然橡胶薄膜。按照Sturm法在22±2°C的温度下进行生物降解。在相同温度的蒸馏水中研究水解降解。通过热物理、光学、光谱和衍射方法控制结构特征。光学显微镜显示，所有样品在接触微生物群和水后表面出现侵蚀。差示扫描量热法表明，在Sturm试验后聚乳酸的结晶度降低了2 - 4%，并且在水作用后结晶度有增加的趋势。红外光谱记录得到的光谱显示了化学结构的变化。由于降解，在3500 - 2900 cm和1700 - 1500 cm区域的谱带强度发生了显著变化。X射线衍射法确定了聚乳酸复合材料中缺陷较多和损伤较小区域衍射图谱的差异。结果表明，纯聚乳酸在蒸馏水作用下比聚乳酸/天然橡胶复合材料更容易水解。薄膜复合材料更容易受到生物降解。聚乳酸/天然橡胶复合材料的生物降解程度随着组合物中天然橡胶含量的增加而提高。
