在这里,报告了手性 2-羟基链烷酸 (2HAA) 基无规共聚物的不对称组合,其单体组成约为 50/50,可形成立体络合物 (SC) 微晶。共聚物组合是l-配置的单独可结晶的聚 ( l-乳酸-co - l -2-羟基丁酸) [P(LLA - co -L-2HB)] (47/53) 或聚 ( l -2-羟基丁酸) acid- co - l -2-hydroxy-3-methylbutanoic acid) [P(L-2HB- co -L-2H3MB)] (49/51) 和d - 单独配置的非结晶性聚 ( d -lactic acid- co -d -2-羟基-3-甲基丁酸)[P( DLA- co -D-2H3MB)](45/55)。每个 SC 微晶的晶面间距值与均聚物 SC 微晶的预期值很好地吻合。这一发现表明,所有四种类型的单体单元共结晶形成 SC 微晶。立体络合 P(LLA- co -L-2HB)/P(DLA- co -D-2H3MB) 和 P(L-2HB- co -L-2H3MB)/P(DLA- co -D- ) 的熔解温度值2H3MB) 混合物的温度范围为 149.3 至 163.6 °C,高于未混合的 P(LLA - co -L-2HB)(84.8 和 88.7 °C)和 P(L-2HB- co ) 观察到的值-L-2H3MB) (61.6–133.1 °C)。该研究显示了l和d构型的手性2HAA基无规共聚物的不对称组合的高 SC 结晶性,即使其中一种是单独不可结晶的。该结果强烈表明当常见的单体单元结合到l和d构型的 2HAA 基无规共聚物中时发生 SC 结晶。新型的l和d构型无规共聚物不对称组合的 SC 结晶有望使手性 2HAA 基聚合物材料的可达到性能和生物降解行为多样化。
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Stereocomplex crystallization behavior and properties of asymmetric combinations of oppositely configured random copolymers based on chiral 2-hydroxyalkanoic acids
Here, asymmetric combinations of chiral 2-hydroxyalkanoic acid (2HAA)-based random copolymers with monomer compositions of approximately 50/50, which can form stereocomplex (SC) crystallites, are reported. The copolymer combinations were l-configured individually crystallizable poly(l-lactic acid-co-l-2-hydroxybutanoic acid) [P(LLA-co-L-2HB)] (47/53) or poly(l-2-hydroxybutanoic acid-co-l-2-hydroxy-3-methylbutanoic acid) [P(L-2HB-co-L-2H3MB)] (49/51) and d-configured individually noncrystallizable poly(d-lactic acid-co-d-2-hydroxy-3-methylbutanoic acid) [P(DLA-co-D-2H3MB)] (45/55). The interplanar distance values of each SC crystallite agreed well with those expected from the homopolymer SC crystallites. This finding indicated that all four types of monomer units cocrystallized to form SC crystallites. The melting temperature values of the stereocomplexed P(LLA-co-L-2HB)/P(DLA-co-D-2H3MB) and P(L-2HB-co-L-2H3MB)/P(DLA-co-D-2H3MB) blends ranged from 149.3 to 163.6 °C, which were higher than the values observed for the unblended P(LLA-co-L-2HB) (84.8 and 88.7 °C) and P(L-2HB-co-L-2H3MB) (61.6–133.1 °C). This study shows the high SC crystallizability of the asymmetric combination of l- and d-configured chiral 2HAA-based random copolymers even when one of them was individually noncrystallizable. This result strongly suggests that SC crystallization occurred when the common monomer units were incorporated into both l- and d-configured 2HAA-based random copolymers. SC crystallization of new types of asymmetric combinations of l- and d-configured random copolymers is expected to diversify the attainable properties and biodegradation behavior of chiral 2HAA-based polymer materials.