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Hybrid SC-polylactide/poly(silsesquioxane) blends of improved thermal stability
Thermochimica Acta ( IF 3.1 ) Pub Date : 2020-05-01 , DOI: 10.1016/j.tca.2020.178592
Agata S. Herc , Piotr Lewiński , Sławomir Kaźmierski , Joanna Bojda , Anna Kowalewska

Abstract Hybrid blends of poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) and hydrogen bonds donating/accepting oligomeric ladder silsesquioxanes (LPSQ-R; R OH, (OH)2, COOH, COOMe) exhibited higher thermal stability at T > 533 K. Temperature of decomposition (Td) increased by 20–30 K comparing to neat PLLA/PDLA, even when small amounts of the additives were used. Stereocomplexation in PLLA/PDLA blends was improved with the addition of H-bond donating LPSQ-R, even in the presence of substantial amounts of the additives, and only slightly disturbed by LPSQ-COOMe. Vibrational spectroscopic analysis was used to follow the crystal structure evolution at 448 K. The modes characteristic of 31 β-helical structures were observed in the studied samples. LPSQ-R grafted with thioglycerol moieties, significantly increased the stereocomplexation rate. Nuclear magnetic resonance spectroscopy (NMR) and wide-angle X-ray scattering (WAXS) measurements confirmed the stereocomplex structure of the hybrid blends. All the observed effects may be related to the specific structure of polysilsesquioxanes and R groups.

中文翻译:

具有改进热稳定性的混合 SC-聚丙交酯/聚(倍半硅氧烷)混合物

摘要 聚(L-丙交酯)/聚(D-丙交酯)(PLLA/PDLA)和给予/接受氢键的低聚梯形倍半硅氧烷(LPSQ-R;R OH、(OH)2、COOH、COOMe)的杂化混合物表现出更高的T > 533 K 时的热稳定性。与纯 PLLA/PDLA 相比,分解温度 (Td) 增加了 20–30 K,即使使用少量添加剂也是如此。PLLA/PDLA 共混物中的立体络合通过添加 H 键捐赠 LPSQ-R 得到改善,即使在大量添加剂存在的情况下,也仅受到 LPSQ-COOMe 的轻微干扰。振动光谱分析用于跟踪 448 K 下的晶体结构演变。在研究样品中观察到 31 种β-螺旋结构的模式特征。LPSQ-R 接枝硫代甘油部分,显着提高立体络合率。核磁共振波谱 (NMR) 和广角 X 射线散射 (WAXS) 测量证实了混合混合物的立体复合结构。所有观察到的影响可能与聚倍半硅氧烷和 R 基团的特定结构有关。
更新日期:2020-05-01
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